Ventura Water Pure Direct Potable Water Reuse

2700 YGNACIO VALLEY ROAD, SUITE 300 • WALNUT CREEK, CALIFORNIA 94598 • P. 925.932.1710 • F. 925.930.0208 pw://Carollo/Documents/Client/CO/WaterRF/9589A00/Deliverables/Ventura Demo Performance Summary_V16_Final.docx

VENTURA WATER

VENTURA WATER PURE DIRECT POTABLE WATER REUSE

DEMONSTRATION PROJECT

SUMMARY REPORT

FINAL JANUARY 2018

January 2018 i pw://Carollo/Documents/Client/CO/WaterRF/9589A00/Deliverables/Ventura Demo Performance Summary_V16_Final.docx

VENTURA WATER

VENTURAWATERPURE DIRECT POTABLE WATER REUSE

DEMONSTRATION PROJECT

SUMMARY REPORT

TABLE OF CONTENTS Page No. 1.0 ACKNOWLEDGEMENTS ............................................................................................ 1 2.0 BACKGROUND AND PROJECT GOALS ................................................................... 1 3.0 REGULATORY PERSPECTIVE AND WATER QUALITY GOALS .............................. 2

3.1 Chemical Removal Goals and Requirements .................................................... 3 3.2 Pathogen Removal Goals and Requirements ................................................... 4 3.3 Overall Potable Reuse Water Quality Goals ..................................................... 4

4.0 DEMONSTRATION FACILITY COMPONENTS AND RELEVANT LITERATURE ...... 5 4.1 Pasteurization .................................................................................................... 5 4.2 Low Pressure Membrane Filtration .................................................................... 8 4.3 Reverse Osmosis .............................................................................................. 9 4.4 UV Advanced Oxidation .................................................................................. 15 4.5 Additional Treatment Components .................................................................. 16

4.5.1 Engineered Storage Buffer (not tested) ........................................... 16 4.5.2 Granular Activated Carbon (not tested) ........................................... 18 4.5.3 Ozone with Biologically Active Filtration (not tested) ....................... 18

5.0 GENERAL PROCESS MONITORING AND PERFORMANCE, THROUGH MARCH 2016 ............................................................................................................. 19 5.1 Pasteurization .................................................................................................. 19 5.2 UF Performance .............................................................................................. 23

5.2.1 Membrane Flux, Permeability and Membrane Cleaning .................. 23 5.2.2 Membrane Turbidity ......................................................................... 28 5.2.3 Removal of Bacteria ......................................................................... 28 5.2.4 Pressure Decay Testing Results and Significance .......................... 29

5.3 RO Performance .............................................................................................. 30 5.3.1 Feed Water Quality .......................................................................... 30 5.3.2 Membrane Performance and Recovery ........................................... 31

5.4 UV AOP Performance ..................................................................................... 32 6.0 RO CHALLENGE STUDIES WITH ADVANCED MONITORING ............................... 34

6.1 Adenosine Triphosphate Reduction through Treatment .................................. 34 6.2 RO, EC, and TOC ............................................................................................ 38

6.2.1 Higher Pathogen Reduction Credit and Higher Confidence in RO System Performance ....................................................................... 38

6.2.2 Overview of RO Performance With Respect to Size Exclusion ....... 39 6.2.3 Electrical Conductivity ...................................................................... 40 6.2.4 Total Organic Carbon ....................................................................... 41

6.3 Trasar/MS2/EC Results and Correlations........................................................ 41 6.3.1 Performance under Normal Operational Conditions ........................ 42 6.3.2 Performance with a Bulk Flow Breach ............................................. 44 6.3.3 Performance with Chlorine Oxidized Membranes ............................ 46

January 2018 ii pw:\\Carollo/Documents\Client/CO/WaterRF/9589A00/Deliverables\Ventura Demo Performance Summary_V16_Final.docx

6.3.4 Trasar Fluorescent Dye Steady State Analysis ............................... 48 6.3.5 Overall Value of Trasar to Potable Reuse ....................................... 48

7.0 RO CONCENTRATE TREATMENT PROOF OF CONCEPT STUDIES ................... 50 7.1 Potential Permit Requirements ........................................................................ 50 7.2 Untreated RO Concentrate Water Quality ....................................................... 52 7.3 Test Protocol ................................................................................................... 53

7.3.1 Test Preparation .............................................................................. 54 7.3.2 RO Concentrate Collection .............................................................. 55 7.3.3 Test 1 - Titration ............................................................................... 55 7.3.4 Test 2 - Calcium and Magnesium Removal ..................................... 55 7.3.5 Test 3 - Metals Removal .................................................................. 56 7.3.6 Test 4 - VOC, SVOC, and NH3 Analysis .......................................... 57 7.3.7 Test 5 - Toxicity Testing pH 9.8 ....................................................... 58 7.3.8 Test 6 - Toxicity Testing pH 11 ........................................................ 59

7.4 Results ............................................................................................................. 59 7.4.1 Ca and Mg Reduction ...................................................................... 59 7.4.2 Metals Reduction ............................................................................. 61 7.4.3 Ammonia .......................................................................................... 65 7.4.4 Toxicity ............................................................................................. 66

7.5 Conclusions ..................................................................................................... 70 7.5.1 Metals .............................................................................................. 70 7.5.2 Toxicity ............................................................................................. 71 7.5.3 Implications to Ventura .................................................................... 71

8.0 DEMONSTRATION OF INNOVATIVE UV ADVANCED OXIDATION SYSTEM ....... 71 8.1 NDMA .............................................................................................................. 74 8.2 1,4-Dioxane ..................................................................................................... 75 8.3 Conclusions ..................................................................................................... 77

9.0 DEMONSTRATION OF TREATMENT SATISFYING DDW REQUIREMENTS FOR POTABLE REUSE ..................................................................................................... 77 9.1 Pathogen Concentrations and Removal .......................................................... 77

9.1.1 Filtered Secondary Effluent Pathogen Levels .................................. 78 9.1.2 Subsequent Disinfection of Filtered Secondary Effluent to Meet

Potable Water Pathogen Standards ................................................ 79 9.1.3 Finished Water (UF/RO/UV AOP and pasteurization/UF/RO/UV

AOP) ................................................................................................ 80 9.2 Chemical Pollutant Concentrations and Removal ........................................... 81

9.2.1 Filtered Secondary Effluent .............................................................. 81 9.2.2 RO Concentrate ............................................................................... 84 9.2.3 TOC Removal by RO ....................................................................... 84 9.2.4 TDS and EC Removal by RO .......................................................... 84 9.2.5 Purified Water .................................................................................. 86

10.0 TOURS, EDUCATION, AND OUTREACH ................................................................ 99 10.1.1 VenturaWaterPure Tour ................................................................. 100 10.1.2 VenturaWaterPure Survey Results ................................................ 101 10.1.3 Bren School at UCSB .................................................................... 103

11.0 CONCLUSIONS ....................................................................................................... 103 12.0 REFERENCES ........................................................................................................ 104

January 2018 iii pw:\\Carollo/Documents\Client/CO/WaterRF/9589A00/Deliverables\Ventura Demo Performance Summary_V16_Final.docx

LIST OF APPENDICES

APPENDIX A – BREN SCHOOL REPORT

LIST OF TABLES Table 3.1 Treatment Goals for Potable Reuse................................................................. 3 Table 3.2 Pathogen Concentration End Goals for Drinking Water ................................... 4 Table 4.1 Summary of Demonstration-Scale Pilot Skid Design Criteria ........................ 10 Table 4.2 Summary of Membrane Specifications .......................................................... 11 Table 4.3 Chemical Feed Information for RO ................................................................ 12 Table 4.4 RO Cleaning Chemicals and Dates ............................................................... 13 Table 4.5 RO Operational Details .................................................................................. 14 Table 6.1 ATP Water Quality Criteria Suggested by Luminultra .................................... 36 Table 7.1. VWRF NPDES Limits ..................................................................................... 51 Table 7.2. RO Concentrate Water Quality ...................................................................... 52 Table 7.3. Sample IDs and pH for Ca and Mg Removal Testing .................................... 56 Table 7.4. Sample IDs and pH for Metals Removal Testing ........................................... 57 Table 7.5 Sample IDs and pH for SVOC and VOC Removal Testing ............................ 58 Table 7.6 Sample IDs and pH for Toxicity Testing pH 9.8 ............................................. 58 Table 7.7 Sample IDs and pH for Toxicity Testing pH 11 .............................................. 59 Table 7.8 Ca and Mg Reduction Results ....................................................................... 60 Table 9.1 Pathogen Removal Through Purification Processes...................................... 80 Table 9.2 CEC Concentrations in Secondary Effluent and Relevant Human Health

Criteria ........................................................................................................... 81 Table 9.3 UF/RO/UV AOP Finished Water Quality for MCLs- Inorganic Chemicals

per Table 64431-A and Table 64432-A (DDW, 2015) .................................... 87 Table 9.4 UF/RO/UV AOP Finished Water Quality for MCLs- Radionuclides per Table

64442 AND 64443 (DDW, 2015) ................................................................... 88 Table 9.5 UF/RO/UV AOP Finished Water Quality for MCLs- Synthetic Organic

Chemicals - SVOCS per Table 64444-A (DDW, 2015) .................................. 89 Table 9.6 UF/RO/UV AOP Finished Water Quality for MCLs- Synthetic Organic

Chemicals - VOCS per Table 64444-A (DDW, 2015) .................................... 90 Table 9.7 UF/RO/UV AOP Finished Water Quality for MCLs- Disinfection Byproducts

per Table 64533-A (DDW, 2015) ................................................................... 92 Table 9.8 UF/RO/UV AOP Finished Water Quality for Secondary MCLs per Tables

64449-A and 64449-B (DDW, 2015) .............................................................. 94 Table 9.9 UF/RO/UV AOP Finished Water Quality for Drinking Water NLs per

DDW, 2015a ................................................................................................... 95 Table 9.10 UF/RO/UV AOP Finished Water Quality for CECs ........................................ 97

LIST OF FIGURES Figure 2.1 Schematic of VenturaWaterPure Demonstration Facility ................................. 2 Figure 4.1 Pasteurization System at the VenturaWaterPure Demonstration Facility ........ 6 Figure 4.2 Pasteurization System Operational Schematic ................................................ 6 Figure 4.3 Ultrafiltration System at the VenturaWaterPure Demonstration Facility ........... 9 Figure 4.4 Reverse Osmosis System at the VenturaWaterPure Demonstration

Facility ............................................................................................................ 10 Figure 4.5 Ultraviolet Light Advanced Oxidation System at the VenturaWaterPure

Demonstration Facility ................................................................................... 16

January 2018 iv pw:\\Carollo/Documents\Client/CO/WaterRF/9589A00/Deliverables\Ventura Demo Performance Summary_V16_Final.docx

Figure 5.1 Disinfection of Filtered Secondary Effluent Total Coliform Bacteria by Pasteurization at Ventura (Ventura Water, 2014) .......................................... 20

Figure 5.2 Disinfection of Seeded MS2 Virus in Filtered Secondary Effluent by Pasteurization at Ventura (Ventura Water, 2014) .......................................... 20

Figure 5.3 Pasteurization Temperature Over the Duration of Testing ............................. 22 Figure 5.4 Total and Fecal Coliform in Pasteurized Effluent ........................................... 22 Figure 5.5 Free Chlorine and Chloramine Concentrations Across Membrane

Processes With and Without Pasteurization in Operation ............................. 23 Figure 5.6 Ultrafiltration System Flux .............................................................................. 25 Figure 5.7 Ultrafiltration System TMP and CIPs.............................................................. 26 Figure 5.8 Temperature Corrected UF Permeability ....................................................... 27 Figure 5.9 Ultrafiltration System Turbidity ....................................................................... 28 Figure 5.10 UF Feed and Filtrate Bacteria Results ........................................................... 29 Figure 5.11 UF PDT Results ............................................................................................. 30 Figure 5.12 RO Feed Water Chemistry-Part 1 .................................................................. 31 Figure 5.13 RO Feed Water Chemistry-Part 2 .................................................................. 31 Figure 5.14 LP UV Dose Response Relationship of Ad2 (Gerba et al., 2002) .................. 33 Figure 5.15 Destruction of Trace Pollutants by UV AOP (Hokanson et al., 2011) ............ 33 Figure 6.1 Trasar System Platform and Control .............................................................. 35 Figure 6.2 Damaged O-Ring ........................................................................................... 35 Figure 6.3 Nalco Team .................................................................................................... 36 Figure 6.4 Reduction of cATP Through RO, Test 1, Including O-ring Damage Test ...... 37 Figure 6.5 Reduction of cATP Through RO, Test 2 (Log Scale Used for Clarity) ........... 38 Figure 6.6 Reduction of cATP Through RO, Test 3, with Chlorine Oxidized

Membranes .................................................................................................... 38 Figure 6.7 Membrane Separation Capabilities ................................................................ 40 Figure 6.8 Correlation of Trasar, Electrical Conductivity, and MS2 LRV (Log

Reduction Value), "Normal" Operation, Stage 1 RO Performance ................ 42 Figure 6.9 Correlation of Trasar, Electrical Conductivity, and MS2 LRV (Log

Reduction Value), "Normal" Operation, Total Permeate RO Performance .... 43 Figure 6.10 Correlation of Trasar, Electrical Conductivity, and MS2 LRV (Log Reduction

Value), "Normal" Operation, Stage 1 RO Performance (Repeat Testing) ...... 43 Figure 6.11 Correlation of Trasar, Electrical Conductivity, and MS2 LRV (Log Reduction

Value), "Normal" Operation, Total Permeate RO Performance (Repeat Testing) .......................................................................................................... 44

Figure 6.12 Comparison of Trasar, Electrical Conductivity, and MS2 LRV (Log Reduction Value) Data, "Normal" Operation (Average Values, First Day of Testing) ..... 44

Figure 6.13 Comparison of Trasar, Electrical Conductivity, and MS2 LRV (Log Reduction Value) Results, "Normal" Operation (Average Values, Second Day of Testing) ................................................................................. 45

Figure 6.14 Trasar, Electrical Conductivity, and MS2 LRV (Log Reduction Value) Correlations, Cut O-Ring, Stage 1 RO Performance ..................................... 46

Figure 6.15 Trasar, Electrical Conductivity, and MS2 LRV (Log Reduction Value) Correlations, Cut O-Ring, Total Permeate RO Performance ......................... 46

Figure 6.16 Trasar, Electrical Conductivity, and MS2 LRV (Log Reduction Value) Correlations , Oxidized Membranes, Stage 1 RO Performance .................... 47

Figure 6.17 Trasar, Electrical Conductivity, and MS2 LRV (Log Reduction Value) Correlations, Oxidized Membranes, Total Permeate RO Performance ......... 47

Figure 6.18 Log Removal Value (LRV) of Trasar and Electrical Conductivity as a Function of Time to Steady State After Process Change (Example 1) .......... 49

January 2018 v pw:\\Carollo/Documents\Client/CO/WaterRF/9589A00/Deliverables\Ventura Demo Performance Summary_V16_Final.docx

Figure 6.19 Log Removal Value (LRV) of Trasar and Electrical Conductivity as a Function of Time to Steady State After Process Change (Example 2) .......... 49

Figure 7.1 pH Calibration Curve ...................................................................................... 55 Figure 7.2 Ca Removal with pH ...................................................................................... 60 Figure 7.3 Mg Removal with pH ...................................................................................... 61 Figure 7.4 Hardness Removal with pH ........................................................................... 61 Figure 7.5 Total Metals Removal with pH ....................................................................... 62 Figure 7.6 Total Metals – Regulated (NPDES) Concentrations (for VWRF) for

Different pH Conditions .................................................................................. 63 Figure 7.7 Dissolved Metals Removal with pH .............................................................. 63 Figure 7.8 Dissolved Metals – Regulated (NPDES) Concentrations (for VWRF) for

Different pH Conditions .................................................................................. 64 Figure 7.9 Zinc, Nickel, and Copper Solubility Curve

(http://www.porexfiltration.com/learning-center/technology/precipitation-microfiltration/) ............................................................................................... 65

Figure 7.10 Ammonia Concentrations at Different pH Values........................................... 66 Figure 7.11 Thalassiosira Pseudonana Toxicity at Different pH and Dilution Values ....... 67 Figure 7.12 Ceriodaphnia Dubia Reproduction at Different pH and Dilution Values ......... 68 Figure 7.13 S. Capricornutum Algal Growth at Different pH and Dilution Values ............. 69 Figure 7.14 Topsmelt Survival rates at various pH values ................................................ 70 Figure 8.1 UV Reactors (Big and Small) ......................................................................... 73 Figure 8.2 Electrodes (Removed From the Pressure Vessel Ahead of the UV Reactor) 74 Figure 8.3 RO Permeate and UV Effluent NDMA Concentrations .................................. 75 Figure 8.4 Destruction of Trace Pollutants by UV AOP (from Hokanson et al., 2011) .... 76 Figure 8.5 Destruction of 1,4-dioxane by UV AOP .......................................................... 77 Figure 9.1 Virus Concentrations in Filtered Secondary Effluent...................................... 79 Figure 9.2 EC Values across UF and RO ....................................................................... 85 Figure 9.3 Comparison of EC and TDS Values............................................................... 86 Figure 10.1 Screenshot of Detailed Website on Potable Water Reuse

(http://www.cityofventura.net/water/sustainable-water) .................................. 99 Figure 10.2 VenturaWaterPure Brochure ........................................................................ 100 Figure 10.3 VenturaWaterPure Tour Photo and Example Banner (Banners Shown

for Each Treatment Process at the Demonstration Facility) ......................... 100 Figure 10.4 Pre and Post Tour Survey of the Support for Potable Water Reuse in

Ventura ........................................................................................................ 102 Figure 10.5 Relative Support for IPR versus DPR .......................................................... 102 Figure 10.6 Regulatory Support Translates into Public Support ..................................... 103

January 2018 1 pw:\\Carollo/Documents\Client/CO/WaterRF/9589A00/Deliverables\Ventura Demo Performance Summary_V16_Final.docx

Ventura Water DPR DEMONSTRATION STUDY

1.0 ACKNOWLEDGEMENTS The VenturaWaterPure direct potable reuse (DPR) demonstration facility represents the combined efforts of Ventura Water, the City of Ventura, Carollo Engineers, and members of the Water Research Foundation Project 4536 team. Funding for this project was provided by Ventura Water and by the Water Research Foundation, with donated time and support from Carollo Engineers. Within Ventura Water, extensive assistance was provided by engineering staff, operations staff, maintenance staff, and laboratory staff. This report also includes the effort and funding from other sources, including Nalco/Ecolab, Neptune Benson, and the San Jose Water Company. Their contributions are also appreciated.

2.0 BACKGROUND AND PROJECT GOALS The work presented here focuses entirely on work efforts with Ventura Water. The far majority of data collected here, and engineering efforts taken to gather this data, were paid for directly by Ventura Water or were donated by Carollo Engineers. That said, the extent of this work and the success of this work would not have reached the same height or provided the same value without the support of the Water Research Foundation. The 4536 effort pertaining to this Ventura demonstration effort and details water quality and blending issues, is summarized in the main 4536 report.

The VenturaWaterPure demonstration facility (demo) was designed to have multiple barriers for both pathogens and trace pollutants in excess of the treatment required for indirect potable reuse (IPR) via groundwater injection (as detailed in CDPH (2014)). The ~20 gallon per minute (gpm) process train (Figure 2.1) takes tertiary effluent (sand filtered effluent, undisinfected) from the Ventura Water Reclamation Facility (VWRF) and provides treatment through pasteurization, ultrafiltration (UF), reverse osmosis (RO), and an ultraviolet light (UV) advanced oxidation process (AOP). For a future DPR facility, granular activated carbon (GAC) may be added after RO for an additional barrier to trace pollutants. Pasteurization may be moved after the GAC in this application. An engineered storage buffer (ESB) would be added to the treatment train after the UV AOP to allow for appropriate system monitoring and water quality assurance.

The primary purpose of the demo was to document the high quality of purified reclaimed water through extensive water quality testing and to understand the impact of blending this purified water with the conventional finished potable water. A secondary purpose of the demo was to provide an educational opportunity for the community, including Ventura Water and City of Ventura staff, the general public, and for local regulators.


Figure 2.1 Schematic of VenturaWaterPure Demonstration Facility

The research documented within this report focuses on a process by process analysis in parallel with an overall water quality analysis. For each key treatment process, the research evaluated the performance (and conservatism) of monitoring systems using a critical control point (CCP) philosophy. A CCP is where: (1) control can be applied to an individual unit process to reduce, prevent, or eliminate process failure; and (2) monitors are used to confirm the CCP is functioning correctly. For this work, CCPs correspond to individual treatment processes that provide control for pathogens (including the provision of log reduction credits) and chemical constituents. Through a combination of treatment system monitoring, CCP control, and overall water quality monitoring, Ventura Water can have confidence in the quality of the purified water produced from the VenturaWaterPure demonstration facility.

3.0 REGULATORY PERSPECTIVE AND WATER QUALITY GOALS Within this report, the project team has detailed the water quality after different levels of treatment and purification. Each treatment process provides either pathogen removal, pollutant removal, or a combination of pathogen and pollutant removal. Within this report, the performance of each treatment process is documented and compared against industry standards and expectations (Table 3.1), with check marks indicating compliance. The final water quality is also compared with DDW regulations for IPR (CDPH, 2014), with the focus on pathogen and chemical concentrations in the finished water.


Table 3.1 Treatment Goals for Potable Reuse VenturaWaterPure Direct Potable Water Reuse Demonstration Project Water Research Foundation

12-log Removal of Virus

10-log Removal of Giardia

10-log Removal of

Cryptosporidium

Meeting Drinking

Water MCLs

Reducing/ Removing

Trace Pollutants

Notes: (1) Check mark indicates compliance with regulatory criteria.

3.1 Chemical Removal Goals and Requirements

A large number of chemicals known to be detrimental to human health above certain concentrations are regulated through maximum contaminant levels (MCLs). Drinking water must be treated to meet these standards regardless of the source. Therefore, any treated effluent that is proposed for supply augmentation should be tested for the full suite of these compounds.

Besides the chemical (and radiological) constituents explicitly regulated through MCLs, a wealth of research has been conducted on the concentrations of unregulated trace organic constituents (TOrCs) in wastewater, their attenuation through conventional WWTPs, and their further breakdown during advanced treatment (Baronti et al., 2000; Lovins et al., 2002; Schäfer et al., 2005; Sedlak et al., 2006; Steinle-Darling et al., 2010; Linden et al., 2012; Salveson et al., 2010; Snyder et al., 2012, and many others). These constituents include pharmaceuticals, personal care products, consumer chemicals, flame retardants, and others, some of which have endocrine disrupting, carcinogenic, and/or other potentially harmful properties at sufficiently high concentrations. Due to this fact (and some help from media interest), this group of constituents has often been the cause of more public concern than the pathogens discussed below. However, the vast majority of TOrCs are present in treated effluent, if at all, at concentrations that are not of concern for human health (Trussell et al., 2013). Further, various research projects document the ability of advanced treatment to meet stringent water quality standards (Trussell et al., 2013, Salveson et al., 2010, Salveson et al., 2014, Linden et al., 2012).

Disinfection byproducts (DBPs) are another suite of parameters that warrant consideration for potable reuse projects. Conventional DBPs, such as trihalomethanes (THMs), Haloacetic Acids (HAAs), bromate, and chlorate, are regulated by the Stage 1 and Stage 2 Disinfectant and Disinfection Byproduct Rules (USEPA, 1998 and 2006a). N-Nitrosodimethylamine (NDMA) and other nitrosamines have been considered for regulation by the USEPA for over a decade (they are on the Unregulated Contaminant Monitoring Rule 2 list and the Candidate Contaminant List 3), and NDMA has a California Notification Level of 10 nanograms per liter (ng/L), which is considered the minimum treatment benchmark by the California utilities currently implementing potable reuse.


3.2 Pathogen Removal Goals and Requirements

With respect to current drinking water regulations, the pathogens of primary concern for potable reuse include enteric viruses, such as Adenovirus, Norovirus, and Enterovirus, and the protozoa Giardia and Cryptosporidium. In some cases, enteric bacteria (such as Salmonella) are also considered. Because treated effluent is generally not considered an acceptable “source water” under existing drinking water regulations (it is neither a groundwater, nor a surface water, nor a groundwater under the influence of surface water), the treatment requirements in current drinking water regulations are generally considered inadequate for the protection from the health risk presented by pathogens. Therefore, additional requirements for pathogen control that are specific to potable reuse have been developed by DDW (CDPH, 2014).

Water treatment regulations for pathogens are predicated on reducing the risk of infection to minimal levels. Table 3.2 identifies the concentration end goals for targeted pathogens that correspond to a modeled, annual risk of infection of 1 in 10,000 or less (Trussell et al., 2013). DDW used this risk level to develop their pathogen criteria (CDPH, 2014) and NWRI used this risk level to develop their pathogen criteria (NWRI, 2013).

Table 3.2 Pathogen Concentration End Goals for Drinking Water VenturaWaterPure Direct Potable Water Reuse Demonstration Project Water Research Foundation

Pathogen Giardia (cysts/L)

Cryptosporidium (oocysts/L)

Enteric virus (MPN/L)

Potable goal 6.80E-06 3.00E-05 2.22E-07 Notes: (1) End goals are based on achieving a risk level of 1 in 10,000 annual risk of infection as listed by

Trussell et al. (2013).

3.3 Overall Potable Reuse Water Quality Goals

The National Research Council (NRC, 2012) has determined that the use of advanced purification processes, such as those employed at the Ventura demonstration facility, will produce a high quality water that is as safe, or safer, than conventional water supplies in the United States. For advanced treatment trains, most chemicals are not detected; those that are detected are found at levels lower than those found in conventionally treated drinking water supplies (NRC, 2012). Further, NRC (2012) concludes that the risk from pathogens in potable reuse “…does not appear to be any higher, and may be orders of magnitude lower, than currently experienced in at least some current (and approved) drinking water treatment systems (i.e., de facto reuse).”

For any future potable reuse system employed by Ventura, the advanced treatment systems and advanced monitoring systems would be designed meet or exceed the water qualities detailed by the NRC (2012).


4.0 DEMONSTRATION FACILITY COMPONENTS AND RELEVANT LITERATURE

Presented here is a summary of anticipated performance of each advanced treatment process. The upstream primary and secondary treatment plant, and the subsequent sand filtration system that feeds the demonstration facility, is not detailed here. New research was conducted on the processes described below, and that work is detailed further on in this report.

4.1 Pasteurization

The pasteurization unit at the demonstration facility is presented in Figure 4.1. The pasteurization concept for reclaimed water disinfection is patented by the Pasteurization Technology Group. Pasteurization provides robust disinfection of pathogens using waste heat. The waste heat can come from many sources. In the case of Ventura Water, the waste heat would come from (future) gas engines or turbines which would be making power for the VWRF. The waste heat is transferred to the water stream through fin and tube heat exchangers, and the vast bulk of the heat is kept within the reactor using plate and frame heat exchangers to constantly transfer heat from the outgoing water (which begins hot and ends cold) to the incoming water (which begins cold and ends hot). A schematic of the pasteurization system is provided in Figure 4.1.


Figure 4.1 Pasteurization System at the VenturaWaterPure Demonstration Facility

Figure 4.2 Pasteurization System Operational Schematic


Extensive wastewater and reclaimed water pasteurization research has now been completed at four locations (3 in CA, 1 in Australia). At each of these sites, seeded and indigenous pathogens and indicator organisms have been exposed to a range of temperatures and water qualities, sufficient to demonstration the dose/response nature of pasteurization to bacteria, virus, and protozoa. These tests have been done on bench-scale apparatus, pilot-scale systems, and full-scale systems, as detailed below:

• Santa Rosa, California ( Carollo Engineers, 2007) – The original "Title 22" testing of pasteurization was completed in Santa Rosa California in 2006 and 2007. That work resulted in regulatory approval of pasteurization based upon a target temperature of 176.4 degrees F and a contact time of 7.7 seconds. For the listed contact time and temperature, that work demonstrated that 5-log kill of poliovirus can be conservatively demonstrated by disinfecting 4-log of seeded MS2 coliphage. That work also documented that MS2 coliphage is a conservative surrogate for a wide range of other virus.

• Ventura, California (2014a) – A full-scale (0.5-mgd system with full-scale components) demonstration of pasteurization was performed over a period of two years in Ventura California. That work demonstrated the disinfection of MS2, total coliform, and fecal coliform through multiple components of the pasteurization system (preheater, stack heater, contact chamber, and again on the preheater), showing robust performance. The extensive nature of the virus disinfection data set resulted in regulatory approval of a lower temperature of 162 degrees F for Title 22 applications at contact times as low as two seconds, increasing the economic value of pasteurization. For the same testing, total coliform was disinfected to below detection at temperatures of 155 degrees and above. Further, the demonstration testing in Ventura documented two types of fouling of the heat exchangers, biological and mineral. The mineral fouling occurred at temperatures well above the operating range, making mineral fouling a non-issue in Ventura. The biological fouling was a slow and continual occurrence, but readily mitigated by chemical cleaning on a monthly basis (shock dosing of sodium hypochlorite appeared to be the best solution).

• Graton, California (Carollo Engineers, 2014b) – The Graton full-scale pasteurization system came online near the end of the Ventura demonstration testing. The virus disinfection results closely mirrored the Ventura work, resulting in a regulatory approval of 162 degrees F at a contact time of 10 seconds to meet the 5-log virus kill requirements for non-potable water reuse in California.

• Melbourne, Victoria, Australia (Sanciolo et al., 2015) – This latest and most comprehensive analysis of pasteurization was undertaken by Victoria University, Melbourne Water, Carollo Engineers, and the Pasteurization Technology Group, with funding from the Australian Water Recycling Centre of Excellence and Melbourne Water. Extensive bench-scale analysis further demonstrated the conservative nature


of the MS2 surrogate, showing robust disinfection of a range of bacteria, virus, and protozoa at different temperatures and contact times. Demonstration-scale testing, using the same unit employed by Ventura in 2012 to 2014, again demonstrated robust MS2 disinfection, this time treating unfiltered secondary effluent (as opposed to a filtered secondary effluent). New information from this project was the complete kill of Giardia and Cryptosporidium by pasteurization at temperatures as low as 131 degrees F after 15 seconds of contact time. Measured log reduction for Cryptosporidium ranged from >2.5 to >3.8 log.

Overall Performance: Following pasteurization at temperatures of 162 degrees F and above, the research documents 5+ log reduction of virus and 3.8+ log reduction of protozoa.

4.2 Low Pressure Membrane Filtration

The ultrafiltration unit, provided by TORAY, is shown in Figure 4.3. The pilot unit utilizes two membrane cassettes with the TORAY HFU-2020N membrane. The nominal pore size of this membrane is 0.01 micron (0.01 um). The TORAY HFU-2020N Membrane is constructed of a hydrophilic, nonionic polyvinylidene fluoride polymer. The membrane utilizes outside/in hollow fibers, thus the flow of water is from the outside to the inside of the hollow fiber. Each membrane element contains approximately 9,000 hollow fibers with an active fiber length of approximately 70 inches. The active membrane surface area of a module is 775 ft2. The outer diameter of the hollow fiber is 1.4 mm and the fiber inner diameter is 0.9 mm. Two different types of potting material are used for the HFU-2020N: an Epoxy or Urethane Resin. The TORAY HFU-2020N Membrane is chlorine tolerant.

Recent work with Clean Water Services (Oregon), as part of DPR demonstration testing, indicates that a well-functioning UF (0.01 µm nominal pore size) can attain 4.7-log reduction of seeded virus (Clean Water Services (CWS) 2014) without chemical use (such as alum or polymer) ahead of the membrane. Equivalent or greater reduction of protozoa can be assumed based upon this data, and is directly supported by NSF (2012). For the particular membrane in question, the TORAY HFU-2020N, extensive performance validation was done by MHW (2012). Virus rejection was documented, with seeded virus (MS2) rejection of 1.7 to 4.8 log reduction over a range of membrane fouling conditions, with the higher removal values occurring during fouled conditions. Testing of the identical Toray membrane by Carollo in Altamonte Springs (Altamonte Springs, 2017) documented 2.4 to 2.5 log removal of seeded MS2 after 9 months of continuous operation of those membranes without any form of membrane repair.

According to the Long Term 2 Enhanced Surface Water Treatment Rule (USEPA, 2006b), the maximum Giardia or Cryptosporidium removal credit that a membrane filtration system is eligible to achieve is the lower of the two values verified as follows:

• Removal efficiency verified during challenge testing.


• Maximum Log Removal Value (LRV) that can be verified during direct integrity testing (DIT) at normal operating conditions.

The MWH (2012) analysis included seeding and removal analysis of 0.5 um latex microspheres, with over 5-log removal consistently demonstrated, with the single lowest removal value of >4.5-log. The use of Direct Integrity Testing (DIT) to continuously prove protozoa log removal was also completed, which included testing of performance with and without compromised membranes. The goal of this testing was to document the ability of the DIT to detect membrane failures and thus potential pathogen removal failures. Two protozoa removal models were used (Darcy's model and Hagen-Poiseulle). The Darcy's model was shown to be consistently conservative whereas the Hagen-Poiseulle model was shown to have nearly a 1:1 correlation with measured results.

Based upon using MF or UF membranes that have undergone extensive performance validation, and based upon maintaining membrane integrity sufficient to maintain a target DIT, both MF and UF membranes can be relied upon for 4+ log reduction of protozoa. Virus removal can also be anticipated for this UF membrane, but DIT monitoring methods are not designed for virus removal monitoring.

Overall Performance: The UF system under evaluation at the demonstration facility reliably provided at least 4-log protozoa removal and 2+ log virus removal. As a measure of conservatism and because virus removal with UF is not well characterized with current online monitoring, no virus credit is assumed.

Figure 4.3 Ultrafiltration System at the VenturaWaterPure Demonstration Facility

4.3 Reverse Osmosis

A two-stage demonstration-scale RO unit was used for this study (Figure 4.4). The demonstration-scale unit mimics the hydraulics of a full-scale RO skid and accurately simulates full-scale pressures and water quality. It does this with a 2-to-1 pressure vessel array configuration and high-pressure feed and interstage booster pumps. A summary of


design criteria for the demonstration-scale pilot skid and specifications for the membranes used during testing are presented in Tables 4.1 and 4.2, respectively.

Over the duration of the 9-month demonstration testing, different chemical feed strategies were used, as well as different cleaning strategies, as shown in Tables 4.3 and 4.4. Acid addition to reduce pH to 6.5 was employed for the majority of RO operation to minimize mineral scaling.

Figure 4.4 Reverse Osmosis System at the VenturaWaterPure Demonstration Facility

Table 4.1 Summary of Demonstration-Scale Pilot Skid Design Criteria VenturaWaterPure Direct Potable Water Reuse Demonstration Project Water Research Foundation

Component Design Criteria Comments

Hydraulic Design

Production Rate Range: 15-18 gpm Feed Flow Rate: 16 to 30 gpm Concentrate Flow Rate: 2 to 30 gpm

Array Two stage array, 2:2:1:1

Cartridge Filter

Type: glass fiber wound or polypropylene Length: 10 inch Number of elements: 6 Nominal pore size: 5 micron

Booster Pump

1.5 hp, 480 v, 3 ph, 60 hz, 3 FLA

Feed Pump Grundfos model CRN10-16 (15 hp, 480 v, 3 ph, 60 hz, 21 FLA) VFD controlled

Interstage Boost Pump

Grundfos model CRN3-11 (2 hp, 480 v, 3 ph, 60 hz, 3.4 FLA) VFD controlled


Table 4.1 Summary of Demonstration-Scale Pilot Skid Design Criteria VenturaWaterPure Direct Potable Water Reuse Demonstration Project Water Research Foundation

Component Design Criteria Comments

Pressure Vessels

Codeline, 4-inch diameter, maximum pressure: 300 psi

Three 3-element and three 4-element vessels to simulate full scale 6 or 7-element vessels

Membrane Elements

4-inch diameter x 40-inches long Stage 1: Up to 14 elements Stage 2: Up to 7 elements

Chemical Feed Pumps and Tanks

Acid Pump: LMI model A971-352SI (0.42 gph) Scale inhibitor: LMI model P131-392SI (0.42 gph) 30-gallon Scale Inhibitor tank with low level switch

Acid and scale inhibitor dosage are manually set. Used drums for acid.

Table 4.2 Summary of Membrane Specifications VenturaWaterPure Direct Potable Water Reuse Demonstration Project Water Research Foundation

Parameter Specification

Manufacturer CSM

Model RE4040-FEn

Surface Area per Element 85 ft2

No. of Elements 18

Element Diameter 4 inch


Table 4.3 Chemical Feed Information for RO VenturaWaterPure Direct Potable Water Reuse Demonstration Project Water Research Foundation

Date Anti-Scalant

Chemical Feed Rate Notes

7/13 - 19/2015 PWT Spectraguard

2.5 mL/min Start-up

7/20 - 23/2015 Nalco PC-191T (with Trasar)

9 mL/min Trasar testing

7/24 - 8/18/2015 PWT Spectraguard

8.8 mL/min

8/18/2015 - 4/10/2016

PWT SG350 9.5 mL/min

The RO system was run over a range of recoveries and permeate production rates. In general, the system was fed a flow of ~15 gpm and at a recovery of 75 percent to 80 percent. Specific goals for RO operation are shown in the Table 4.5.


Table 4.4 RO Cleaning Chemicals and Dates VenturaWaterPure Direct Potable Water Reuse Demonstration Project Water Research Foundation

Date Cleaning Chemicals Procedures Notes

7/24/2015 Opticlean A(1) 1) Recirculated both stages simultaneously for approx. 1.5 hrs. • Second stage membranes severely fouled with minerals, requiring an acid-based cleaning chemical.

• Opticlean A unable to restore performance. Second stage membranes were replaced. • Performance restored

8/6/2015 Opticlean B(2), then Opticlean A

1) Recirculated both stages simultaneously for approx.. 1.5 hrs. 2) System was flushed with feed water after each chemical application.

• First stage membranes fouled, likely biologically, requiring non-acid cleaning with Opticlean B.

• Second stage membranes fouled, likely mineral fouling, requiring Opticlean A. • Performance restored

8/18/2015 Opticlean A 1) Recirculated each stage separately for approx. 1.5 hrs. • First stage membranes fouled, likely biologically. Potentially connected to increased biofouling of upstream UF. Opticlean B used.

• Performance restored. 9/1/2015 Opticlean B,

then Opticlean A

1) Recirculated each stage and chemical separately for approx. 1.5 hrs. 2) System was flushed with feed water after each chemical application.

• First stage membranes fouled, likely biologically, requiring non-acid cleaning with Opticlean B.

• Second stage membranes fouled, likely mineral fouling, requiring Opticlean A. • Performance restored. System run for 3 months with marginal fouling.

12/21/2015 Opticlean B 1) Recirculated each stage separately for approx. 1.5 hrs. • System to be shut down for temporary process modifications. Opticlean B used to remove biological fouling.

12/22/2015 Preservol(3) 1) Circulated through both stages after cleaning completed on 12/21/2105. 2) Chemical flushed out with booster pump on 1/5/2016.

• System to be shut down for temporary process modifications. Preservol used to minimize biological fouling.

1/5/2016 Opticlean B 1) Recirculate both stages simultaneously for approx. 1.5 hrs. 2) Soak overnight. 3) Recirculate both stages simultaneously for approx. 1.5 hrs.

• Opticlean B used to remove biological fouling and prepare system for operation.

Notes:

(1) Surfactants with an acid. (2) Surfactants without an acid. (3) Preservol is a chemical preservative added to mitigate biological regrowth on the membrane surface during an extended shutdown period. It is not a cleaning chemical.


Table 4.5 RO Operational Details

VenturaWaterPure Direct Potable Water Reuse Demonstration Project Water Research Foundation

Membranes Units CSM RE4040 FEn

Recovery % 80

Feed pH --- 6.5

Flux Stage 1 gfd 11.5

Stage 2 gfd 10.9

Overall Average gfd 11.3

Flow Rate Feed gpm 15

Stage 1 Permeate gpm 8.1

Stage 1 Concentrate gpm 6.9

Total Permeate gpm 12

Total Concentrate gpm 3

Studies have found virus removal by RO to be from 3 to >6-log (Reardon et al., 2005, NRMMC/EPHC/NHMRC 2008, CWS 2014). Equal or greater removal is expected for protozoa based upon size differences (protozoa being much larger than virus). Unfortunately, RO process performance for pathogen rejection is not governed by the ability of an intact membrane to reject pathogens; it is governed by the ability to monitor process integrity (Reardon et al., 2005 and Schäfer et al., 2005). The monitors currently used, electrical conductivity (EC) meters and total organic carbon (TOC) meters, can measure 99 percent or less removal of both parameters through the RO process. Recently, the DDW granted 1.5 log reduction credit for all pathogens for RO (WRD, 2013), based upon a requirement to continuously monitor TOC reduction across RO. The Orange County Water District current attains 2-log pathogen credit through their online TOC meters. Alternative technologies, such as online fluorescent dye monitoring, have been shown to have higher accuracy in assessing membrane efficiency (Kitis et al., 2003, Henderson et al., 2009, Pype et al., 2012). Using traditional monitoring technology, we recommend using the 2.0-log reduction value for all pathogens for RO at this time. However, as documented further on in this report, online testing of fluorescent dyes at the VenturaWaterPure demonstration facility suggest 3 to 4+ LRV through RO.

RO has been shown to remove compounds that are not typically attenuated by MF or UF. Membranes, in particular reverse osmosis membranes, provide high removal rates for trace


level pollutants (Salveson et al., 2010, Snyder et al., 2007). Extensive research has been completed on the type of contaminants removed by RO and expected removal rates based on compound charge and size. RO membranes are highly efficient at removing trace level pollutants at higher molecular weights, with low-molecular weight organic acids and neutral compounds being removed partially, including both NDMA, 1,4-dioxane, and certain disinfection byproducts (DBPs) (Bellona et al., 2008). Having an advanced oxidation process, or an additional barrier for the treatment of NDMA and 1,4-dioxane is a highly effective treatment train to ensure contaminant removal, and is required for potable water reuse projects in California.

Overall Performance: The RO system under evaluation at the demonstration facility did reliably provide at least 1.5-log removal of both protozoa and virus based upon standard monitoring processes (e.g., EC). As shown further on, testing at the demonstration facility documented 4+ log removal of virus (and thus also 4+ log removal of protozoa) under normal operating conditions. RO also provides for substantial removal of trace pollutants.

4.4 UV Advanced Oxidation

The UV AOP unit, provided by Neptune Benson (now owned by Evoqua Water Technologies), is shown in Figure 4.5. This UV system utilizes medium pressure UV lamps to provide disinfection and to pair with an oxidant (H2O2 in this case) to result in an advanced oxidation process. Additionally, this UV system included electrodes ahead of the UV lamps that generated a current within the flow stream. The work at Ventura demonstrated that the electrode system, when combined with UV, also resulted in an AOP without the need for a dosed oxidant.

Through AOP (either with the electrodes or the oxidant), hydroxyl radicals are created to destroy organic chemical pollutants. In particular, DDW (CDPH, 2014) requires the UV AOP to provide at least 0.5 log reduction of 1,4-dioxane, a conservative surrogate for destruction of trace pollutants by UV AOP. Oxidant additions (either H2O2 or NaOCl) are typically in the range of 3 to 5 mg/L.


Figure 4.5 Ultraviolet Light Advanced Oxidation System at the VenturaWaterPure

Demonstration Facility

In the event of pathogens passing through RO, the UV process provides for a high level of disinfection. At a dose of 800+ mJ/cm2, as is applied for this project, the high UV dose will result in 6+ log reductions of all target pathogens (USEPA 2006c; Hijnen et al., 2006, Rochelle et al., 2005), including Cryptosporidium, Giardia, and adenovirus. Higher reductions are theoretically possible, but the DDW allows only a maximum of 6-log reduction credits per any one treatment technology (CDPH, 2014).

Additionally, NDMA, with a DDW notification level (NL) of 10 ng/L, can pass through RO at low concentrations (typically 20 to 100 ng/L), requiring destruction by UV photolysis (Sharpless and Linden, 2003). Therefore, it is common to set the UV dose at 800+ mJ/cm2 or higher. This high UV dose photolyzes NDMA as well as many other smaller chemicals that may have passed through the RO train.

Overall Performance: The UV AOP system under evaluation at the demonstration facility reliably provided at least 6-log disinfection of both protozoa and virus. The same system reduced NDMA to <10 ng/L and destroyed at least 0.5-log of 1,4-dioxane, and thus also reducing other trace level pollutants.

4.5 Additional Treatment Components

Several treatment systems/components were not evaluated during the demonstration system that may or will be incorporated into the future full-scale system. These are discussed below.

4.5.1 Engineered Storage Buffer (not tested)

Potable water reuse projects have, with a few exceptions (e.g., Big Spring Texas), use an environmental buffer as part of the treatment/conveyance infrastructure. Such a buffer can be a surface water body or a groundwater basin, in which the purified reclaimed water is


placed into the buffer and later withdrawn as a potable water supply. The benefits of the buffer can include:

• Biodegradation of chemical pollutants

• Filtration of pathogens

• Dilution of both pollutants and pathogens with ambient water

• Die-off of pathogens based upon time

• Response retention time (RRT)

The key benefit of the environmental buffer, in the view of this project team, is the RRT, which is time to monitor water quality and response to water quality concerns prior to the consumption of water by the public (e.g., travel time in the groundwater basin as the water is sampled at monitoring wells and results are obtained prior to extraction of the groundwater prior to consumption).

Recent potable reuse reports suggest that the benefits of an environmental buffer can be overcome with an Engineered Storage Buffer (ESB). These studies include the WateReuse Research Foundation's 2011 report entitled "Direct Potable Reuse: A Path Forward" (Tchobanoglous et al., 2011), the National Research Council's 2012 report entitled "Water Reuse: Potential for Expanding the Nation's Water Supply Through Reuse of Municipal Wastewater" (NRC 2012), the Australian Academy of Technological Sciences and Engineering’s 2013 report entitled “Drinking Water through Recycling: The benefits and costs of supplying direct to the distribution system” (ATSE 2013), and the WateReuse Research Foundation Project 11-10, Application of Risk Reduction Principles to Direct Potable Reuse (Salveson et al., 2014). They suggest that a higher level of treatment at the Advanced Water Treatment (AWT) facility can compensate for the treatment, and dilution provided by the groundwater aquifer or surface water reservoir.

Tng et al. (2015) collected a cumulative 64 years' worth of operating data from seven operating advanced treatment facilities around the world to calibrate a model that simulated failure events for potable water reuse. One of the significant findings of the modeling effort by Tng et al. (2015) is that "the best approach to improving a plant’s resilience is not by having multiple redundancies, but rather, via implementing more efficient maintenance protocols with an adequate amount of treated water storage." This second point dovetails with the findings from WRRF 12-06 (Salveson et al, 2016), which defines a framework for engineered storage buffer sizing as a function of monitoring system characteristics and robustness as opposed to redundant treatment, essentially providing a roadmap for the approach recommended by Tng et al. (2015).


The Engineered Storage Buffer, properly used in place of an environmental buffer, provides substantial value. For communities without available environmental buffers such as rivers or aquifers potable water reuse is still a possibility with ESBs. Second, ESBs eliminate the need for costly pumps and pipes to and from environmental buffers. Third, depending upon the location, purified water can be lost in the environmental buffer, either washed downstream or dispersed through an aquifer. Finally, advanced treated water is typically higher in quality than groundwater or surface water. Environmental sources can be easily contaminated with runoff and influences. Keeping the treated water separate from these sources can lower contamination and decrease further treatment costs.

For a future DPR project in Ventura, the ESB would hold the finished water for a duration sufficient to fully monitor the performance of each key process and respond any potential performance issue. This hold time is the "Failure and Response Time", or FRT (Salveson et al., 2016). The FRT can be minimized by not taking credit for processes that require long sampling and analysis time frames. Advanced processes such as RO, and UV AOP can be rapidly monitored and maintain FRT values of ~30 minutes or less.

ESB also provides disinfection due to the maintenance of a free chlorine residual. Free chlorine Ct values required for Giardia and virus inactivation are defined by the 1990 Surface Water Treatment Rule (SWTR) Guidance Manual (USEPA 1990). The Ct tables in that reference are flexible. 4-log virus credit can be obtained at a Ct of 12 mg-min/L, though higher Cts would be required for Giardia credit. USEPA (1990) was only designed to meet a maximum 4-log virus kill, though higher virus kill has been demonstrated. For a minimum FRT of 30 minutes and a minimum residual of 1 mg/L, the Ct of 30 mg-min/L will result in the 4+ log reduction of virus and 0.5-log reduction of Giardia, but no reduction of Cryptosporidium.

4.5.2 Granular Activated Carbon (not tested)

Granular activated carbon (GAC) was not included as part of this demonstration project, but could be included as part of a future DPR treatment scheme. GAC could be placed after RO process, providing a second barrier to removal of trace pollutants. GAC is proven to reduce a wide range of trace pollutants at different efficiencies, typically ranging from 20 percent to 80 percent, though some removals are greater (up to 99 percent) while others are <10 percent (Snyder et al., 2007). The primary value would be for GAC to reduce infrequent spikes of unknown origin that may pass through an RO process.

4.5.3 Ozone with Biologically Active Filtration (not tested)

Ozone with Biologically Active Filtration (O₃/BAF) is another process tool that can provide reduction of both chemical and pathogen pollutants, but was not included as part of this


project. Such a process could be placed ahead of membrane filtration (MF or UF), providing the following benefits:

• Oxidation of chemical pollutants, including trace level hormones and pharmaceuticals, by O₃.

• Disinfection of pathogens by O₃, either virus only based upon O₃/TOC ratios without using a residual or virus and protozoa based upon the use of EPA CT criteria.

• Reduction of bulk TOC and trace level chemical pollutants by BAF.

• Filtration of pathogens by BAF, depending upon turbidity reduction goals.

These extensive values for O₃/BAF are well documented in the research literature. As one prime example, we refer the reader to Altamonte Springs (2017).

5.0 GENERAL PROCESS MONITORING AND PERFORMANCE, THROUGH MARCH 2016

The demonstration facility has been in operation since the start of July (2015) and was shut down in early April 2016, representing 9 months of operation. The data presented here represents operational data (e.g., online measurements) and general water quality data (e.g., grab samples for basic analysis, such as for total coliform). This data is intended to demonstrate effective operation of the treatment processes and to develop important information for a future design project with Ventura Water. Detailed water quality data pertaining to health standards and innovative treatment and monitoring is detailed in subsequent sections of this report.

5.1 Pasteurization

The pasteurization system for this demo was designed to disinfect at a temperature of 162 degrees F, which is the DDW approved temperature to attain 5-log reduction of virus. Prior testing of pasteurization at Ventura complete disinfection of bacteria at temperatures as low as 155 degree F (Ventura Water, 2014). Higher temperature values are required to obtain the 5-log virus removal target from DDW, with data from Ventura indicating a minimum temperature of 161 degrees F (Ventura Water, 2014).


Figure 5.1 Disinfection of Filtered Secondary Effluent Total Coliform Bacteria by

Pasteurization at Ventura (Ventura Water, 2014)

Figure 5.2 Disinfection of Seeded MS2 Virus in Filtered Secondary Effluent by Pasteurization at Ventura (Ventura Water, 2014)

At a feed flow of ~22 gpm, the heat exchangers for the pasteurization unit were only able to attain a peak temperature of 158 degrees F, still providing substantial reduction of virus,

1

10

100

1000

104

105

106

.01 .1 1 5 10 20 30 50 70 80 90 95 99 99.9 99.99

Filtered Effluent135 F145 F140 F150 F155F

Tota

l Col

iform

, MP

N/1

00m

L

0

1

2

3

4

5

6

7

8

174.5 163.8 161.4

Viru

s Lo

g R

educ

tion

Temperature, Degrees F


protozoa, and bacteria. Hitting the temperature of 162 degrees F is not critical for this study, as the goals of pasteurization for this project are:

• To evaluate the potential impact and value of pasteurization pretreatment ahead of UF on UF efficiency due to reduced biological activity.

• To evaluate the potential improvement in overall water quality with pasteurization part of a DPR treatment train (as part of the larger 4536 project).

To those ends, the project team monitored the peak temperature of the pasteurization system as well as several other parameters. The pasteurization system was run from February (starting 2/7/2016) through April, as shown in Figure 5.3. This figure also highlights fouling of the pasteurization system, which was cured through the use of a sodium hypochlorite CIP (clean in place). The pasteurization system did provide substantial bacteria disinfection, as shown in Figure 5.4. These results demonstrate the importance of maintaining a sufficiently high target temperature to result in robust disinfection. When temperatures dropped during periods of fouling, bacteria counts rose.

Chloramines were dosed into the feed to the demonstration facility at a constant rate to provide a residual across both the UF and RO membranes. Figure 5.5 examines the chlorine residual across the purification trains. The project team's hypothesis was that the disinfection provided by pasteurization (Figure 5.4) may result in a lower chlorine demand (due to reduced microbiological activity such as biofilms) and thus a higher residual. The results did not support this hypothesis. After some initial issues at startup, a chlorine residual of ~2.5 mg/L (total) with minimal free chlorine residual, was used for membrane maintenance. Turning pasteurization on at ~158 degrees F did not change the chlorine residual as they carried through the purification processes.

Beginning on 3/31/2016, the chloramine feed to the UF was turned off, as part of an effort to understand if pasteurization alone can provide sufficiently disinfected feed water that minimizes membrane fouling. The results of this test are reviewed in the following section.


Figure 5.3 Pasteurization Temperature Over the Duration of Testing

Figure 5.4 Total and Fecal Coliform in Pasteurized Effluent

15 mg/L free chlorine rinse for 60 minutes conducted on 3/16/2016 to reduce biofouling, result was an increase in flow through the system and improved heat transfer.


Figure 5.5 Free Chlorine and Chloramine Concentrations Across Membrane Processes With and Without Pasteurization in Operation

5.2 UF Performance

The UF process has been run in two modes. The initial operation of the Toray membrane was done with both of the two membrane modules in operation, resulting in a relative low membrane flux (~18 gfd). Once the team became comfortable with the UF, the UF flux was raised to a much higher value (35 gfd). This higher flux represents a potentially large savings for a future UF installation for Ventura Water. Two phases of operation were used. The longest phase fed the UF with sand filtered effluent. The second, and shorter, phase of work for this project fed the UF with a sand filtered effluent that was first disinfected with pasteurization.

5.2.1 Membrane Flux, Permeability and Membrane Cleaning

In summary, the UF system has been operating at 35 gfd, 95 percent recovery since August 20, 2015 (Figure 5.6). For Ventura Water, the use of 35 gfd for a design flux for the tested membrane is reasonable. Over the operational period, July through April, there were no maintenance cleans (MCs) performed. However, the system went through 6 CIPs (clean in place) procedures:

• 08/19/2015 (sodium hypochlorite and citric acid);

• 10/7/2015 (sodium hypochlorite and citric acid);

• 12/22/2015 (sodium hypochlorite and phosphoric acid);



• 3/2/2016 (sodium hypochlorite and citric acid).


Over the duration of operation, the TMP values were maintained between 6 psi (after CIP) to 24 psi (just before a CIP). The UF system demonstrated the ability to run continuously for more than two months between CIPs. The CIPs repeatedly recovered the permeability of the UF membranes (Figures 5.7 and 5.8). Note, the system did go offline for several periods of time due to difficulties with different pilot and monitoring equipment; where no data exists, the system was not online.

The impact of pasteurization, with and without chloramine feed, is also seen in the graphs below. The project team's hypothesis was that pasteurization ahead of the UF membrane would provide sufficient disinfection to allow membrane operation without chloramine feed. This hypothesis was supported by the data. Chloramination was off for the majority of the last UF run cycle (~5 weeks), with that run cycle showing a similar gradual rise in TMP to all other data sets, followed by a flat period with no TMP rise with run time. Temperature corrected permeability provided the same conclusions, that the UF membrane could be run without chloramine feed as long as pasteurization was in operation. Note, this data set is admittedly small, and the impact of longer operation without chloramine feed remains uncertain.


Figure 5.6 Ultrafiltration System Flux


Figure 5.7 Ultrafiltration System TMP and CIPs


Figure 5.8 Temperature Corrected UF Permeability


5.2.2 Membrane Turbidity

Feed turbidity to the UF was a filtered secondary effluent, for the most part below 2 NTU. The UF membrane consistently reduced turbidity to below 0.2 NTU. Grab sampling correlated well with online metering for the UF feed, but not for the UF filtrate (Figure 5.9). The Toray membrane has been able to consistently produce a filtrate turbidity of <0.02 NTU at the Ventura facility as well as at other facilities (e.g., San Diego demonstration facility), lending credibility to the online turbidity results presented in the figure below.

Figure 5.9 Ultrafiltration System Turbidity

5.2.3 Removal of Bacteria

The UF showed consistent removal of both E. coli and total coliform, with UF filtrate fecal coliform numbers below detection (<1 MPN/100mL). Influent counts for both were greater than 1600 to 2419 MPN/100 mL during the early phases of testing when the chloramine concentrations were low (or non-existent). After chloramines were consistently dosed in the ~2 mg/L range, both total coliform and E. coli where reduced to <100 MPN/100 mL prior to UF (Figure 5.10).

Ventura Water was initially running standard multiple tube fermentation analysis, but then transitioned to an IDEXX analysis. For potable water reuse projects, the IDEXX provides for a more rapid turn-around of data (<24 hours), which provides greater water quality confidence to field and engineering staff. IDEXX provides an indicator species quantification system called “Quanti-Tray” that can be used with any of its indicator detection reagents (Colilert for total coliform and E. coli, Enterolert for enterococci, Pseudalert for Pseudomonas aeruginosa). The Colilert Quanti-Tray method is US EPA approved for raw


and drinking water (regular 24-hour TAT) and is consistent with Standard Methods for the Examination for Water and Wastewater and replaced the multiple tube method as the recommended process under ISO 9308-2:2012 for "Water Quality - Enumeration of Escherchia coli and coliform bacteria - Part 2 :Most Probable Number method."

For Ventura Water's device, the Quanti-Tray/2000, the quantification range is from 1 to 2,419 MPN per 100mL. The accuracy of the Colilert-18 test was evaluated by Chao et al. (2004), who found that false positive and false negative rates for 7.4 percent and 3.5 percent, respectively, for E. coli and 9.6 percent and 6.3 percent, respectively, for total coliforms. This compared very favorably to other false positive and false negative rates cited by the authors.

Figure 5.10 UF Feed and Filtrate Bacteria Results

5.2.4 Pressure Decay Testing Results and Significance

The log reduction credit for the UF system, for protozoa, can be calculated based upon the work in this report. The Toray UF has proven the 4+ log removal of protozoa for their system based upon maintaining a pressure decay test (PDT) result of 0.3 psi/min using the Hagan Poiseuille formula or 0.09 psi/min using the Darcy Pipe formula. There were occasions where the PDT was >0.09 psi/min, but the higher value was due to a faulty air valve on the pilot unit which was periodically corrected by Toray staff. No membranes have been pinned (fixed, plugged) since the start of testing. The PDT results are shown in Figure 5.11. These PDT values are then used in conjunction with other operational data to calculate log reduction values, as defined in MWH (2012) for this particular membrane. Those calculations show >4-log protozoa removal.


Figure 5.11 UF PDT Results

5.3 RO Performance

5.3.1 Feed Water Quality

As part of this study, Ventura Water began monitoring the quality of secondary effluent to help characterize the concentration of various minerals that affect RO recovery. When concentrated as a result of the RO process, these minerals can form salts that can foul RO membranes and downstream brine waste disposal infrastructure. RO recovery (as a percent) was selected to avoid precipitation of these mineral salts.

Figures 5.12 and 5.13, with data over a two month period, shows relatively stable values with time for hardness, calcium, magnesium, silica, alkalinity, bicarbonate, chloride, and sulfate. Iron levels (not shown) were in the range of 0.05 to 0.13 mg/L and carbonate values were below detection. It should be noted, however, that rain events, drought conditions, industrial discharge can affect the diurnal, seasonal or annual quality of the feed water in (in this case filtered secondary effluent). The project team recommends the continued monitoring these minerals and even develop a diurnal program if industrial discharge is expected to influence the diurnal quality of effluent seen by the RO system.

For the purposes of this study, the data that has been collected will be used to establish a design basis for recovery. This recovery should be considered in the context of the limited


period over which the data was collected and safety factors should be applied to ensure reliable operation of the RO system.

Figure 5.12 RO Feed Water Chemistry-Part 1

Figure 5.13 RO Feed Water Chemistry-Part 2

5.3.2 Membrane Performance and Recovery

Overall, the RO system has performed well, and operated at a recovery of ~80 percent at ~ 11 gfd. Residual chloramines from the UF filtrate reach the RO system at approximately


1.5 mg/L, which appears adequate for controlling biological growth on the RO membranes. To control inorganic fouling, three pretreatment chemical alternatives have been tested. Water quality modeling indicated that antiscalant alone may be adequate to control potential inorganic fouling. The first alternative tested was Spectraguard (from PWT), which is typically used for brackish groundwater and other similar applications, at a dose of approximately 2 mg/L. The second alternative was SG 350 (from PWT), which is formulated to reduce calcium phosphate scaling, at a dose of approximately 2 mg/L. The third alternative included the combination of SG 350 (approximately 2 mg/L) and acid addition to pH 6.5. In general, the SG 350 alone worked slightly better than the Spectraguard alone. However, the acid addition was needed to maintain long-term stable operation of the RO system. The RO system was operated with the combination of SG 350 (approximately 2 mg/L) and acid addition to pH 6.5.

5.4 UV AOP Performance

The UV AOP system was only put into operation during system tours, during sampling events, and as part of concentrated research efforts detailed in subsequent sections.

For potable water reuse applications, the UV system provides three important benefits. First, it disinfects virus, protozoa, and bacteria. No measurable concentrations of these pathogens are typically found in RO permeate, but the added disinfection is needed to further reduce pathogen concentrations and provide an additional safety barrier. For UV disinfection, the most resistant known pathogen is Adenovirus. The dose response relationship of Ad2 as well as other viruses is shown in Figure 5.14, demonstrating that Ad2 is a conservative surrogate for a wider range of virus. Adenoviruses comprise a large group of serologically different viruses that can cause a broad spectrum of diseases with varying severity (USEPA, 2010). Research on the dose-response relationship of Adenoviruses, using Low Pressure (LP) UV radiation on a bench-scale collimated beam setup, is mainly limited to Adenovirus types 2, 40, and 41. The dose response relationship at high UV doses (>200 mJ/cm2) is more widely published for Adenovirus type 2 (Ad2), and shows that 6-log reduction of Ad2 may be obtained at a dose of 235 mJ/cm2 (Gerba et al., 2002).

Second, the UV system destroys NDMA, a pollutant that must be reduced to below 10 ng/L (parts per trillion). UV is proven to destroy NDMA through photolysis, with 90 percent removal based upon a UV dose of ~900 mJ/cm2 (Sharpless and Linden, 2003). Third, the UV process, when combined with an oxidant (H2O2 or NaOCl) will generate hydroxyl radicals which destroy a wide range of trace level pollutants (Hokanson et al., 2011, Figure 5.15).

For the installed UV system, the feed concentration of NDMA ranged from 22 to 32 ppt, with an average of 25 ppt, whereas the finished water (after the high dose UV system) had an NDMA concentration of <2 ppt in most cases. The result is a log reduction of NDMA of 1.1, which correlates to a UV dose of ~1,000 mJ/cm2 (or higher). Such a high dose, per Gerba


et al. (2011), will provide 6+ log reduction of all pathogens of concern and provide advanced oxidation with the addition of hydrogen peroxide.

Figure 5.14 LP UV Dose Response Relationship of Ad2 (Gerba et al., 2002)

Figure 5.15 Destruction of Trace Pollutants by UV AOP (Hokanson et al., 2011)


6.0 RO CHALLENGE STUDIES WITH ADVANCED MONITORING

The fluorescent dye work presented in this section was completed as a primary component of the Texas Water Development Board (TWDB) project (Testing Water Quality in a Municipal Wastewater Effluent Treated to Drinking Water Standards, which will not be published until 2016), and the TWDB has primary publication rights for that work. Funding to cover the work by Nalco was provided as part of that TWDB project. Field time and support for the work documented here was donated by Carollo Engineers as part of this Water Research Foundation Project.

Limited testing was conducted across the UF (including ATP and particle count reduction). Conversely, intensive challenge studies were conducted on the RO system, including "normal" operation, operation with a cut O-ring, and operation with chlorine oxidized membranes. The cut O-ring, as well as the chlorine oxidized membranes1 (two membranes), were placed into the last PV of the Stage 1 RO. Photos from the testing are shown below (Figures 6.1, 6.2, and 6.3). RO system monitoring included electrical conductivity (EC), adenosine triphosphate (ATP), MS2 coliphage (a virus surrogate), and the Trasar fluorescent dye from Nalco.

6.1 Adenosine Triphosphate Reduction through Treatment

Adenosine Triphosphate (ATP) bioluminescence monitoring is a novel method to better understand microbiological activity in a water sample. ATP exists in all living microorganisms (thus, not virus), and generates photos when combined with the enzyme luciferase. The ATP bioluminescence assay is performed by introducing ATP to a solution containing luciferase (derived from fireflies). In the presence of biological activity, light is emitted and detected in a luminometer. For this project, ATP testing was done with the Luminultra system, using the QGA-100C Test Kit. The Luminultra system calculates the cellular ATP (cATP) in picograms (pg) per mL and is a direct indication of planktonic population. Luminultra suggests that cATP levels can be used to demonstrate the performance of a treatment system and the relative purity of water, as shown in Table 6.1, below.

1 A membrane oxidation procedure, developed specifically for this study, was applied to select membrane elements prior to their installation at the pilot site. These elements were exposed to several pulses of feed water containing free chlorine until steady-state salt passage under standard operating conditions increased to approximately 20% (from a nominal 1%). This increase in salt passage represents a 20-fold reduction in selectivity and is thus indicative of significant oxidative damage.


Figure 6.1 Trasar System Platform and Control

Figure 6.2 Damaged O-Ring


Figure 6.3 Nalco Team Table 6.1 ATP Water Quality Criteria Suggested by Luminultra


Application Good

Performance, pg/mL

Preventative Action Needed,

pg/mL

Corrective Action Needed,

pg/mL High-Purity Water <0.1 0.1 to 1.0 >1.0

Water for Consumption <0.5 0.5 to 10 >10

Raw Make-up Water <10 10 to 100 >100

Cooling and Process Water Using Oxidizing Biocides <10 10 to 100 >100

Cooler and Process Water Using Non-Oxidizing Biocides <100 100 to 1,000 >1,000

The detection of microbiological activity is not necessarily a detection of pathogens or a water quality risk, and ATP results should be used to track overall treatment performance based upon long term trends. The Orange County Water District uses cATP in this manner, including tracking microbiological activity through treatment (secondary effluent, membrane filtrate, RO permeate, finished water, and then through monitoring wells). The cATP results are collective over an extended period of time to best understand treatment system performance by monitoring long-term trends (Knoell et al., 2015). Rapid increases in cATP results may suggest a substantial treatment system failure, whereas gradual increases in cATP results may suggest a gradual degradation of performance. With regard to RO monitoring, the cATP results can be used to monitor biofouling of different RO trains and RO stages, allowing the operations team to proactively maintain RO performance (Knoell


et al., 2015). Finally, as reported by Knoell et al. (2015), cATP may be sufficiently sensitive to detect RO membrane performance failures (e.g., glue line leak, O-ring failure).

For this project, a limited series of cATP tests were conducted. Figure 6.4, below, illustrates the reduction of cATP across the RO membranes, including a test with a cut O-ring. For this first test series, MS2 coliphage was injected into the RO influent, substantially increasing the microbiological load on the RO process. Even with that addition, the RO permeate cATP levels were <1 pg/mL (ranging from 0.3 to 0.6 pg/mL), within the acceptable range for "Water for Consumption" as defined by Luminultra, and understanding that this demonstration facility follows RO with a high dose UV system for further disinfection. Importantly, and similar to the OCWD findings (Knoell et al., 2015), the cATP tests were sufficiently sensitive to pick up the water quality breach due to the cut O-ring (resulting in cATP of 1.7 pg/mL).

Figure 6.4 Reduction of cATP Through RO, Test 1, Including O-ring Damage Test

A second series of cATP tests (Figure 6.5) were run without MS2 addition, with these results tracking cATP through UF and RO. For these results, the RO feed cATP levels are reduced (as anticipated due to the lack of MS2). The RO permeate had cATP levels of 0.1 pg/mL, sufficient for "High Purity Water" and more than acceptable for "Water for Consumption" per the Luminultra guidelines. A third and final series of cATP tests (Figure 6.6) were run, this time with MS2 addition, with two chlorine oxidized membranes in the last pressure vessel (PV) of the Stage 1 RO. These results again showed the cATP method as sufficiently sensitive to pick up the RO membrane damage (due to chlorine oxidation).


Figure 6.5 Reduction of cATP Through RO, Test 2 (Log Scale Used for Clarity)

Figure 6.6 Reduction of cATP Through RO, Test 3, with Chlorine Oxidized Membranes

Overall, the cATP results demonstrated:

• A high level of microbiological reduction across UF and RO membranes (>2 log across UV and >1.5 log across RO).

• Sufficient sensitivity to detect RO membrane integrity problems associated with a cut O-ring and chlorine oxidized membranes.

• The potential to be a long term performance monitoring tool for both UF (or MF) and RO processes.

6.2 RO, EC, and TOC

6.2.1 Higher Pathogen Reduction Credit and Higher Confidence in RO System Performance

RO systems for potable water reuse are currently allowed pathogen credits equal to the log reduction of TOC (WRD, 2013), though DDW has indicated that log reduction of EC can


also be used for pathogen credit. CWS (2014) demonstrated that EC and TOC log removal through RO were essentially equivalent using online meters. Demonstrating a higher level of log removal performance can have economic value, and certainly has value in water quality confidence. Regarding the latter, a potable water reuse treatment train in California is required to provide 12-log virus removal and 10-log protozoa removal from the point of raw wastewater to the point of potable water consumption (CDPH, 2014). This log reduction must be provided by a minimum of three treatment technologies. With conventional monitoring of a conventional purification train, the following can be obtained:

• Ultrafiltration - a UF system can obtain 0/4 (virus/protozoa) log credits

• Reverse Osmosis – a RO system can obtain ~1.5/1.5 (virus/protozoa) log credits

• Ultraviolet Light - a UV system can obtain 6/6 (virus/protozoa) log credits.

• In total, the three combined processes can readily obtain 7.5/11.5 (virus/protozoa) log credits

Implementation of a precise and accurate RO monitoring system, such as the fluorescent dye work discussed below, could increase the log credits for RO to 4/4, resulting in a combined total credit of 10/14, which is an improvement in credit by over two orders of magnitude.

Regarding cost, numbers presented here are only rough estimates but do provide an understanding of value. Should a treatment train not have sufficient credits for virus, as an example, an online fluorescent dye system can be implemented and provide the additional 2.5-log credit, and do so at a cost of ~$150,000 or less with limited long-term operational costs. Installing a new disinfectant to gain virus credit, such as free chlorine, UV, or ozone, could cost >$500,000 per mgd to install and have long-term operational costs.

6.2.2 Overview of RO Performance With Respect to Size Exclusion

While RO is technically a “semi-permeable membrane”, constituents smaller 0.1 to 1 nm can pass through RO (Khulbe et al., 2008, Kosutic and Kunst, 2002). A visual presentation of membrane pore size, and the constituents that can be removed by different membranes is presented below in Figure 6.7.

The RO process provides four critical roles in the purification of reclaimed water, all driven by the ability to remove extremely small compounds, chemicals, and pathogens. First, RO removes salts. Second, RO removes bulk organic matter (measured as Total Organic Carbon, TOC). Third, it removes pathogens. Fourth, RO removes trace pollutants. The removal of salts and organic matter is detailed below.


Figure 6.7 Membrane Separation Capabilities

6.2.3 Electrical Conductivity

The RO system was equipped with online EC meters on the influent and the effluent of the RO system. EC has a linear relationship with the total dissolved solids (TDS) in water, but that ratio is site specific. For Ventura, the TDS in the RO feed ranged from 1350 to 1600 mg/L with some variation. EC in the same RO feed was in the 2400 uS/cm range, equating to a ratio of TDS/EC of ~0.6. TDS is commonly referred to as salt, and shown as Aqueous Salt in the above Figure. The EC results are documented previously in this report as part of the long-term analysis. These results show RO permeate EC in the 35 to 70 uS/cm range, which equates to 20 to 40 mg/L of TDS in the RO permeate. The log reduction of EC ranged from 1.3 to 1.8, but many of the lower values are related to different operational issues at startup, and a long term EC reduction of ~1.6 is documented further on in this report. This EC removal is consistent with other research (Clean Water Services, 2014).

TDS, best characterized as NaCl, is in the size range of 250 pm. This small salt is more than 16 times smaller than any known viral pathogens, more than 800 times smaller than any known bacterial pathogens, and more than 80,000 times smaller than any known protozoan pathogens. Because of this size difference, California regulators (DDW) are confident that the log reduction of EC provides a conservative measure of pathogen reduction performance from RO. For a future potable reuse RO system in Ventura, at least 1.5 log reduction of all pathogens can be assumed through RO based upon EC measurements.


6.2.4 Total Organic Carbon

The RO system does not have online TOC meters installed on the RO influent and effluent. For this analysis, weekly grab samples for TOC are being collected and analyzed. RO permeate TOC values are typically below the detection limit (0.5 mg/L), though some values have been shown as high as 0.9 mg/L (well above anticipated values for RO permeate). Because of the high detection limit and due to some of the values being above that limit, the log reduction of TOC did not exceed 1. The TOC reduction in other research typically is in the range of 1.5 or higher (e.g., WateReuse Research Foundation Project 11-02 (Gerringer et al., 2014) showed TOC reduced from 5 mg/L to 0.1 mg/L, a log reduction of 1.7).

As opposed to EC (and TDS), the size of TOC is not well defined. Assuming a properly functioning UF (as is the case for the Toray demonstration membrane), the maximum TOC size will be in the range of 0.01 um, as larger TOC will be rejected by the UF. Kim and Dempsey (2008) performed fractionation of effluent organic matter (EfOM, which can be correlated to TOC), and demonstrated that 19 percent of EfOM is >100 kDa (<0.05 um), whereas the remaining 91 percent was under 100 kDa and 62 percent of the EfOM was <1 kDa (<0.0005 um). With the relatively larger size of the smallest pathogens of concern (enteric virus is 0.01 to 0.1 um, MS2 is 0.027 um, as referenced previously), the reduction of TOC is a conservative surrogate for the reduction of virus. However, as the TOC fractionation literature is very thin, EC (and TDS) removal by RO appear to be a more reliable surrogate for RO performance.

Similar to EC removal, the DDW has determined that because of the small size of TOC, the log reduction of TOC is a conservative measure of pathogen reduction performance from RO. For a future potable reuse RO system in Ventura, at least 1.4 log reduction of all pathogens can be assumed through RO based upon TOC measurements.

6.3 Trasar/MS2/EC Results and Correlations

To provide greater resolution of RO membrane integrity and greater confidence in pathogen removal by RO, testing of the Trasar system by Nalco was done at the demonstration facility. At 600 g/mole, the Trasar fluorescent dye is larger than the openings in the RO membrane, but smaller than the size of any target pathogen (see Figure 6.8), making the Trasar compound a potentially valuable tool for RO system performance monitoring. Due to the size, a small flaw in a RO membrane could be detected by Trasar before pathogen breakthrough. The use of such a fluorescent dye for RO performance monitoring is promising, but several questions must be answered: 1. What log reduction credit does the dye demonstrate with a fully functioning RO

system? 2. How does the dye respond to a bulk flow breach, such as a membrane tear or an

O-ring failure?


3. How does the dye respond to chlorine damage to the RO membrane, in which there is no hydraulic failure (tear or O-ring) but components of the RO membrane are deteriorated due to chlorine exposure?

4. Does the concentration of the Trasar dye accumulate in the system, or does it operate in a steady state condition?

Figure 6.8 Correlation of Trasar, Electrical Conductivity, and MS2 LRV (Log Reduction

Value), "Normal" Operation, Stage 1 RO Performance

To answer these questions, extensive testing by Carollo, with the assistance of Nalco, was done as part of the Ventura demonstration testing. The Trasar compound is stable over a range of temperature (0.08 percent change per degree F change) and is not impacted by pH in the range of 4 to 10. The Trasar fluorometer is able to detect the Trasar compound at concentrations as low as 1 ppb and as high as >100 ppm, allowing for significant calculations of log reduction across RO (>4 log).

The Nalco Trasar system (Photos 2 and 4) includes continuous online monitoring of both EC and the Trasar compound. This information was logged for the duration of testing by the project team. Over a period of three days, the concurrent removal of seeded MS2, EC, and Trasar were monitored for different RO operational conditions, including "normal" operation, a cut O-ring condition, and two chlorine oxidized RO membranes. The performance was tracked across both the first stage of RO and for the entire RO permeate.

6.3.1 Performance under Normal Operational Conditions

Figures 6.9, 6.10, 6.11, and 6.12 illustrate the removal of seeded MS2, EC, and the seeded Trasar compound for two different days, completed in triplicate, under normal operational conditions (no RO flaws). These results show ~6 log reduction (or higher) of MS2,


concurrent with 3 to 4 log reduction of the Trasar compound and 1.4 to 1.7 log reduction of EC. The test results represent the RO performance after the first stage and the total performance including both stages of RO. The data does show a reduced water quality after the second stage, which is picked up by the EC monitoring and the Trasar monitoring, but not the MS2 challenge (Figures 16 and 17). Of the two successful methods (EC and Trasar), Trasar was more sensitive and measured a larger drop in performance.


Value), "Normal" Operation, Total Permeate RO Performance


Value), "Normal" Operation, Stage 1 RO Performance (Repeat Testing)



Value), "Normal" Operation, Total Permeate RO Performance (Repeat Testing)

Figure 6.12 Comparison of Trasar, Electrical Conductivity, and MS2 LRV (Log Reduction

Value) Data, "Normal" Operation (Average Values, First Day of Testing)

6.3.2 Performance with a Bulk Flow Breach Figure 6.2 illustrates the O-ring cut, with the damaged connection piece placed in the last PV of the Stage 1 RO. The O-ring cut had a dramatic impact on performance, with MS2 log reduction dropping from ~6 log to ~1 log. In fact, all the constituents are removed to the


same level of ~0.8 to ~1.0 log (i.e., the LRV for pathogens and any pollutants is simply defined by the fraction of flow that goes through the breach (the O-ring cut) versus the membrane material). In the case of a bulk flow breach, both Trasar and EC effectively determine the pathogen reduction through RO, and both techniques document a substantial failure. However, because Trasar is a more sensitive monitoring technique, the drop from 3 to 4 log removal of Trasar to 1 log removal is more dramatic and would be more visible to operations staff (and thus more of a useful tool). The results from the Bulk Flow Breach tests are shown in Figures 6.13, 6.14, and 6.15).

Figure 6.13 Comparison of Trasar, Electrical Conductivity, and MS2 LRV (Log Reduction

Value) Results, "Normal" Operation (Average Values, Second Day of Testing)


Figure 6.14 Trasar, Electrical Conductivity, and MS2 LRV (Log Reduction Value)

Correlations, Cut O-Ring, Stage 1 RO Performance

Figure 6.15 Trasar, Electrical Conductivity, and MS2 LRV (Log Reduction Value)

Correlations, Cut O-Ring, Total Permeate RO Performance

6.3.3 Performance with Chlorine Oxidized Membranes

Two chlorine oxidized membranes were placed in the last PV of the Stage 1 RO, replacing two of six intact elements in that vessel. With this, two out of 12 total elements in Stage 1 were substituted. For the test, the membrane elements were exposed to several pulses of


feed water containing free chlorine until steady-state salt passage increased from a nominal 1 percent to approximately 20 percent under standard operating conditions. The increased salt passage represents a 20-fold reduction in selectivity and thus indicates significant oxidative damage. The data (Figures 6.16 and 6.17) demonstrate the impact of the chlorine oxidation, which is a reduction in removal performance for EC and Trasar, but no significant reduction in virus removal.

Figure 6.16 Trasar, Electrical Conductivity, and MS2 LRV (Log Reduction Value) Correlations , Oxidized Membranes, Stage 1 RO Performance

Figure 6.17 Trasar, Electrical Conductivity, and MS2 LRV (Log Reduction Value) Correlations, Oxidized Membranes, Total Permeate RO Performance


6.3.4 Trasar Fluorescent Dye Steady State Analysis

The Trasar fluorescent dye, injected at high concentrations, reached steady state influent conditions in a matter of minutes for all tests with one exception (e.g., as shown in Figure 6.18). For the one exception, when the "normal" RO membranes were replaced with the chlorine oxidized membranes, the time to steady state conditions increased (Figure 6.19), but of critical importance was that steady state conditions were attained. For all testing documented here, the RO influent and RO permeate Trasar concentrations were stable.

6.3.5 Overall Value of Trasar to Potable Reuse

Based upon this data set, the following can be said about Trasar performance and value to potable reuse:

• Trasar exhibits sensitivity that is orders of magnitude higher than EC, TOC, ATP, orother tested methods for monitoring RO performance.

• Results from this research demonstrate the ability to conservatively monitor 3 to>4 log removal of virus using Trasar, compared to ~1.5 log removal of othermonitoring surrogates.

• A bulk flow breach was detected and effectively monitored by the Trasar system,recording a dramatic reduction in virus removal performance.

• RO membrane damage due to chlorine oxidation was detected and conservativelymonitored by the Trasar system, noting a reduction in RO performance even thoughMS2 removal was not impacted by the damaged RO membranes.

• No "clumping" or accumulation of the Trasar compound was seen in RO influent, andthe system demonstrated performance and steady state operation over the entirerange of testing.


Figure 6.18 Log Removal Value (LRV) of Trasar and Electrical Conductivity as a Function of Time to Steady State After Process Change (Example 1)

Figure 6.19 Log Removal Value (LRV) of Trasar and Electrical Conductivity as a Function of Time to Steady State After Process Change (Example 2)


7.0 RO CONCENTRATE TREATMENT PROOF OF CONCEPT STUDIES

For a future potable water reuse project in Ventura, the RO concentrate may be discharged in one of several ways, including a possible ocean outfall. One component of this potable water reuse demonstration study was to examine precipitation-based methods for RO concentrate treatment that will result in permit compliance at a reasonably low relative cost.

The work presented below was done outside of the scope and budget of this research grant. The work was a proof of concept study on the use of an elevated pH to precipitate metals and organics, resulting in a higher quality RO concentrate. Analytical testing included both metals and toxicity, as reviewed below.

7.1 Potential Permit Requirements

Permit limits depend upon the receiving water. The permit limitations are different depending on if the receiving water is a bay, estuary, river, or ocean. What follows is a discussion of National Pollutant Discharge Elimination System (NPDES) permit limitations as they apply to Ventura.

The Ventura Water Reclamation Facility (VWRF) discharges treated wastewater into the Santa Clara River Estuary (SCRE). This estuary is treated as a freshwater estuary. Permit limits for ocean discharge are also included, taken from the Calleguas Salinity Management Pipeline (SMP) NPDES permit. The metals concentration and loading limits are shown in Table 7.1.


Table 7.1. VWRF NPDES Limits VenturaWaterPure Direct Potable Water Reuse Demonstration Project Water Research Foundation

SCRE Discharge (VWRF)

Ocean Discharge (Calleguas SMP) (1)

Constituent Unit Average Monthly

Daily Maximum Daily Maximum

Copper µg/L 6.1 14 730

lb/day 0.45 1.1 110

Selenium µg/L 2.9 8.2 4,400

lb/day 0.22 0.62 640

Lead µg/L 7 14 580

lb/day 0.52 1.1 85

Nickel µg/L 7.2 18.8 1,500

lb/day 0.54 1.4 220

Ammonia (June to October)

mg/L 1.07 -- 180

lbs/day 80 -- 26,000

Ammonia (June to

April)

mg/L 1.3 -- 180

lbs/day 98 -- 26,000

Notes: (1) The parameters listed within this table do not have average monthly limits for the Calleguas Salinity

Management Pipeline NPDES Permit.

Regular Whole Effluent Toxicity (WET) testing is required to conform to the permit as well. The VWRF must test for acute as well as chronic toxicity. For acute toxicity, the organism for the 96-hour tests is the fathead minnow (Pimephales promelas). The acute toxicity test measures organism survival (70 percent and higher survival is a passing test under the existing permit). The chronic toxicity test measures other parameters such as growth, fertilization, and reproduction. The organism for the VWRF's chronic toxicity test is the most sensitive of the following three: the water flea (ceriodaphnia dubia - survival and reproduction), the fathead minnow (larval survival and growth), and the green alga (Selenastrum capricornutum - growth). S. capricornutum has been judged the most sensitive and is used as the test species. No specific dilutions were mentioned in the NPDES permit. In order to pass, the organisms must show no observable adverse effects at 100 percent effluent. Toxicity testing is discussed in greater detail in the results section.

Toxicity testing for ocean discharge (as seen in the Calleguas SMP Permit) uses the most sensitive of the following organisms: topsmelt (Atherinops affinis - survival and growth), the purple sea urchin (Strongylocentrotus purpuratus - growth and fertilization), the sand dollar


(Dendraster excentricus - growth and fertilization), the red abalone (Haliotis rufescens - shell development), and the giant kelp (Macrocystis pyrifera - germination and growth). The topsmelt was determined to be the most sensitive to RO concentrate and was used in this experiment. A passing toxicity test demonstrates less than a 25 percent reduction in growth, fertilization, reproduction, or other response measure, using 100 percent effluent.

Partial funding for this RO concentrate evaluation came from the San Jose Water Company related to their interest in potable water reuse in the South San Francisco Bay. Metals limits are slightly higher in this area than in Ventura, and are not included within this summary. The acute toxicity species for the South San Francisco Bay site is rainbow trout (Onchorhynchus mykiss) and a 70 percent survival rate in 100 percent effluent is required. The chronic toxicity test for the South San Francisco Bay site is a type of algae, Thalassiosira pseudonana. To pass, the toxicity test must show that the 100 percent effluent shows no more than a 25 percent reduction in growth as compared to the control.

7.2 Untreated RO Concentrate Water Quality

The following table includes data from a series of testing events prior to the conducting of the RO Concentrate experiment. This data was from testing of the Ventura RO concentrate. Looking at this data, the ammonia, copper, nickel, and selenium concentrations in the RO concentrate exceed the VWRF NPDES limits for a SCRE discharge (highlighted in yellow). However, no constituent in the RO concentrate exceeds a potential NPDES limit for a potential ocean discharge (Calleguas SMP). Table 7.2. RO Concentrate Water Quality


Constituent Unit Average Value

Max Value No. of Samples

Alkalinity mg/L 1078 1159 6

Aluminum ug/L 18 30 5

Ammonia mg/L 2 2 1

Antimony ug/L 1.8 2 5

Arsenic ug/L 5.4 8 5

Beryllium ug/L ND<0.2 5

Cadmium ug/L ND<0.2 5

Calcium mg/L 696 759 2

Chloride mg/L 1746 2935 4

Chloride mg/L 1746 2935 4

Chromium ug/L 3 9 5


Table 7.2. RO Concentrate Water Quality VenturaWaterPure Direct Potable Water Reuse Demonstration Project Water Research Foundation

Constituent Unit Average Value

Max Value No. of Samples

Chromium III ug/L 5.5 1 5

Chromium VI ug/L 0.9 0.5 5

Copper ug/L 9 13 5

Fluoride mg/L 1.4 2 5

Iron ug/L 234 350 5

Lead ug/L 0.7 1.1 5

Magnesium mg/L 298.8 369 5

Manganese ug/L 175.6 359 5

Mercury ug/L 0.1 0.24 5

Nickel ug/L 7.6 10 5

pH pH units 7.57 1

Phosphate mg/L 7.6 9 5

Potassium mg/L 122.8 130 5

Selenium ug/L 18.2 27 5

Silica mg/L 115.5 171 34

Silver ug/L ND<1 5

Sodium mg/L 1344 1430 5

Strontium ug/L 5898 7180 5

Sulfate mg/L 3386 5506 4

TDS mg/L 7448 8142 4

Thallium ug/L ND < 0.2 5

Total Cyanide mg/L ND<0.004 5

Total Hardness mg/L 3034 3326 10

Zinc ug/L 78 90 5

7.3 Test Protocol

The goal of this proof of concept study was to determine if pH adjustment (through caustic soda addition in this case) can remove metals, organics, and improve toxicity in RO concentrate. Based upon experience, the project team focused on magnesium removal, resulting in co-precipitation of the following: hardness, heavy metals (lead, cadmium,


copper, zinc, chromium mercury, arsenic), Barium, Silica, Fluoride, Iron (pH 9.6), Manganese (pH 9.8), Turbidity, Organics (color) –D/DBP, Oil, Algae, bacteria and viruses, and Radium, uranium, gross alpha, beta. The bolded constituents are typically only removed with magnesium removal.

The RO concentrate used for this project was sampled from the Ventura Water Pure DPR demonstration facility in Ventura CA. All laboratory work, with a few exceptions, was conducted at the onsite lab. The dilution water was lab-grade water with no chlorine.

Five total experiments were run within this bench study. The first test created a preliminary titration curve. The second test determined the pH values which correspond to ideal magnesium removal. These tests also set guidelines for mixing time and expected settling time. The third test targeted various pH values to optimize the metals removal. The last two tests prepared samples for toxicity testing.

Because this was a proof of concept experiment outside of the research grant budget, no analysis was conducted more than once. After completing the bench-scale treatment, samples were collected for NPDES compliance parameters:

• Test 1 - Development of preliminary titration curve of a 200 mL sample.

• Test 2 - Jar test to determine Mg, Ca, and hardness removal pH (pH intervals of 0.5 from 9.5 to 11.5).

• Test 3 - Jar test to document metals removal pH (pH increments of 0.2 from 9.6 to 10.4).

• Test 4 - Batch sample preparation of concentrate at pH for magnesium settling. Toxicity tests conducted on these samples.

• Test 5 - Batch sample preparation of concentrate at theoretical pH for copper removal. Toxicity testing conducted on these samples.

7.3.1 Test Preparation

For the duration of the test, the equipment listed below was used:

• Jar testing apparatus (6 containers with 2-L capacities each).

• Carboys (2.5-gallon for transportation of RO concentrate).

• Large collection containers (10-gal, 5-gal) for RO concentrate batch mixing.

• Assorted glassware (beakers, graduated cylinders for measurement).

• Stock solution of sodium hydroxide (5-N), diluted to 95.2 mg/mL.


• pH probe.

• Ca/Mg Reagent Analysis kit (Hach Method 8338, detection range 0-25,000 mg/L as CaCO₃).

• Concentrated hydrochloric acid (for pH adjustment for toxicity testing).

• Concentrate nitric acid (for pH adjustment to store samples for later analysis).

• Titration buret.

7.3.2 RO Concentrate Collection

Due to the size of the collection containers and the distance to the test lab, RO concentrate was collected in 2 - 2.5-gallon carboys for most tests. This means that the collection occurred multiple times throughout the day and there is a likelihood for some variation in RO concentrate water quality.

7.3.3 Test 1 - Titration

To estimate the amount of NaOH needed to reach the desired pH values, a titration curve was created using a sample of 250 mL of RO concentrate. The concentrate was raised from its initial concentration (approximately 7.5) to 11.5. The NaOH and pH was recorded after each addition. NaOH was added in increments of 0.2 mL until the pH reached 9, and then was decreased to 0.1 mL until the pH reached 11.5.

Figure 7.1 pH Calibration Curve

7.3.4 Test 2 - Calcium and Magnesium Removal

1-L of RO concentrate was measured into the six receptacles for the jar testing apparatus. The dose - pH curve created in Test 1 was used to predict estimated NaOH doses used in

y = -2.7321E-07x2 + 2.4027E-03x + 7.5779E+00R² = 9.7671E-01

77.5

88.5

99.510

10.511

11.512

0.0 500.0 1000.0 1500.0 2000.0 2500.0

pH

NaOH Conc (mg/L)

Titration Curve - Test 1


Test 2. Six pH values were targeted to assess calcium and magnesium removal, 9.5, 10, 10.5, 10.75, 11, and 11.5. The samples were dosed to 2 mL less than the predicted dose and then the remaining NaOH was added in increments of 0.2 mL until the desired pH was reached. After the pH was reached, the following mixing sequence was run:

• Rapid Mix: 1 min at 200 rpm.

• Flocculation: 5 min at 20 rpm.

• Settling: 2 hours at 0 rpm.

The pH value was measured again and samples of each pH value (50 mL) were taken for Ca/Mg analysis using Hach Method 8338. The samples were preserved for shipment by reducing the pH to below 2 using concentrated nitric acid. The sample ID's, pH values and NaOH doses are recorded in Table 7.3. Table 7.3. Sample IDs and pH for Ca and Mg Removal Testing


Sample ID Initial pH Target pH [NaOH] (mg/L) Final pH

2.1 7.57 9.5 794 9.39

2.2 7.57 10 1,073 9.9

2.3 7.57 10.5 1,441 10.53

2.4 7.57 10.75 1,407 10.47

2.5 7.57 11 1,479 10.65

2.6 7.57 11.5 1,688 11.04

2.7 7.57 11.5 2,158 11.51

7.3.5 Test 3 - Metals Removal

2 L of RO concentrate was measured into the six jar testing containers. The target pH values for Test 3 were 9.6, 9.8, 10.0, 10.2, and 11. Appropriate doses of NaOH were predicted from the dose - response curve from Tests 1 and 2. After each dose of NaOH, the following mixing sequence was followed:

• Rapid Mix: 1 min at 200 rpm.

• Flocculation: 5 min at 20 rpm.

• Settling: 5 min at 0 rpm.


After each dose and mixing sequence, the pH was measured. When the pH values reached the target, the water sample was allowed to settle for 2 hours. NaOH dose and pH values are shown in Table 7.4. 500 mL of each sample was collected for dissolve metals analysis (200.7/245.1 CCR Title 22, no preservative), 500 mL was collected for total metals analysis (200.7/245.1 CCR Title 22, preserved with nitric acid), and 500 mL was collected for cyanide analysis (SM4500-CN-E, preserved with NaOH). Samples were refrigerated after collection and picked up by the lab the next day. Table 7.4. Sample IDs and pH for Metals Removal Testing


Sample Initial pH Target pH [NaOH] (mg/L) Initial

Adjusted pH

Final pH

3.0 7.57 7.57 0 7.57 7.57

3.1A 7.57 9.6 826 9.53 9.51

3.2A 7.57 9.8 943 9.81 9.74

3.3A 7.57 10 973 10.04 10.04

3.4A 7.57 10.2 1,024 10.19 10.05

3.5A 7.57 10.4 1,245 10.38 10.31

3.6A 7.57 11 1,619 11.08 11.02

7.3.6 Test 4 - VOC, SVOC, and NH3 Analysis

2 L of RO concentrate was measured into the six jar test containers. Three target pH values were selected for Test 4, 9.8, 10.2, and 11. Each pH value had one duplicate in order to provide a sufficient amount of water for the tests. The same pH adjustment procedure as described in Test 3 was followed. The water was allowed to settle for at least two hours before collection. After settling, 1 L of each pH value and the untreated RO concentrate was collected in unpreserved amber glass bottles for semi-volatile organic compounds (SVOC) analysis (Method 625 SVOCs). 3- 40 mL plastic containers preserved with HCl were filled per water sample for volatile organic compound (VOC) analysis (8260B VOCs). 500 mL containers preserved with H2SO4 were used to collect samples for NH3 analysis (SM4500-NH3-D).


Table 7.5 Sample IDs and pH for SVOC and VOC Removal Testing VenturaWaterPure Direct Potable Water Reuse Demonstration Project Water Research Foundation

Sample Target pH [NaOH] (mg/L)

Initial Adjusted pH

Final pH Analysis

4.0 N/A 7.53 7.53 7.53 SVOC, VOC, NH3

4.1A 9.8 966 9.78 9.56 SVOC

4.1B 9.8 961 9.78 9.53 VOC, NH3

4.2A 10.2 1,054 10.15 9.98 SVOC

4.2B 10.2 1,050 10.16 9.97 VOC, NH3

4.3A 11 1,664 11 10.84 SVOC

4.3B 11 1,715 10.79 10.79 VOC, NH3

7.3.7 Test 5 - Toxicity Testing pH 9.8

The goal of this portion of the test was to assess if treating the water to an assumed ideal metals removal pH value (in this case, the target was 9.8 to maximize copper removal) would also reduce toxicity as well. The idea was that, if metals caused toxicity, then the water treated to the metals removal pH would have the lowest toxicity. If other unregulated organic materials caused toxicity, they may be removed through the magnesium flocculation and therefore the magnesium removal pH (assumed to be pH 11 for this test) would have a lower toxicity.

Two 5-gallon buckets were used to collect approximately 4.5 gallons of RO concentrate in each. The pH of each was adjusted to 9.8 using NaOH. The samples were mixed using wooden stirrers and allowed to settle for two hours. The supernatant liquid was collected in various sized containers for toxicity testing. After collection, the pH of the supernatant was adjusted to near a pH of ~7-8 using concentrated HCl.

Table 7.6 Sample IDs and pH for Toxicity Testing pH 9.8 VenturaWaterPure Direct Potable Water Reuse Demonstration Project Water Research Foundation

Sample ID Initial pH [NaOH] (mg/L) Adjusted pH pH After

Neutralization(1) 5.1A 7.54 1024 9.81

7.25, 7.4, 7.94 5.1B 7.54 1068 9.8

Notes: (1) Multiple pH values are shown within this category because three different toxicity samples were

adjusted within their respective collection containers.


7.3.8 Test 6 - Toxicity Testing pH 11

Approximately 9 gallons of RO concentrate was collected in a large container to prepare for toxicity testing. The pH was adjusted to 11 using NaOH. The sample was mixed thoroughly through shaking the container and allowed to settle for two hours. The supernatant liquid was collected in various sized containers for toxicity testing. After collection, the pH of the supernatant was adjusted to near a pH of ~7-8 using concentrated HCl.

Table 7.7 Sample IDs and pH for Toxicity Testing pH 11 VenturaWaterPure Direct Potable Water Reuse Demonstration Project Water Research Foundation

Sample ID Initial pH [NaOH] (mg/L) Adjusted pH pH After

Neutralization(1)

6.1 7.53 1693 10.96 7.02, 7.71, 7.4 Notes: (1) Multiple pH values are shown within this category because three different toxicity samples were

adjusted within their respective collection containers.

7.4 Results

7.4.1 Ca and Mg Reduction

The calcium and magnesium analysis was conducted at the lab at Carollo's Walnut Creek Office. Table 7.8 shows the results. As a general trend, both Mg and Ca decrease as the pH is increased. A pH value of "minimum solubility” was not seen. The concentrations consistently decreased with increase in pH. This downward trend in solubility can be seen in Figures 7.2 and 7.3. Removal of total hardness is shown in Figure 7.4.


Table 7.8 Ca and Mg Reduction Results VenturaWaterPure Direct Potable Water Reuse Demonstration Project Water Research Foundation

Sample ID

Treated pH

[Ca2+] as mg/L CaCO₃

[Ca2+] (mg/L)

[Mg2+] as

mg/L CaCO₃

[Mg2+] (mg/L)

Total Hardness

(mg/L CaCO₃)

Test Hardness

Range (mg/L as CaCO₃)

Untreated ROC 7.53 2,300 920 1,220 296 3,520 2000-5000

2.1 9.39 676 270 828 201 1,504 400-1000

2.2 9.9 508 203 812 197 1,320 400-1000

2.3 10.53 234 94 66 16 300 0-500

2.4 10.47 210 84 70 17 280 0-500

2.5 10.65 194 78 352 86 546 0-500

2.6 11.04 146 58 106 26 252 0-500

2.7 11.51 38 15 12 2.9 50 0-500

Figure 7.2 Ca Removal with pH

0100200300400500600700800900

1000

7 8 9 10 11 12

[Ca2

+] (m

g/L)

pH

pH vs [Ca2+]


Figure 7.3 Mg Removal with pH

Figure 7.4 Hardness Removal with pH

7.4.2 Metals Reduction

Total metals concentrations over the different pH values are shown in Figure 7.5. There appears to be very good zinc and aluminum removal as the pH increases. However, there is little removal of copper or other metals as the pH increases. The concentrations of copper fluctuate between the method detection limit (MDL) and the practical quantitation limit (PQL).

0

50

100

150

200

250

300

350

7 8 9 10 11 12

[Mg+

] (m

g/L)

pH

pH vs [Mg2+]

0

500

1000

1500

2000

2500

3000

3500

4000

7 8 9 10 11 12Tota

l Har

dnes

s (m

g/L

as C

aCO

3)

pH

pH vs Total Hardness (mg/L as CaCO3)


Figure 7.5 Total Metals Removal with pH

The concentrations of regulated metals are shown in Figure 7.6, with NPDES discharge limits shown for the Ventura SCRE permit. Total copper concentrations are below the limits in all samples except for the pH of 9.51 and 10.04. Selenium exceeds permit limits in all samples, but this result was expected. Selenium is not well removed with pH adjustment and typically requires additional chemical addition to improve removal. Nickel also exceeds permit limits in all samples.

0

20

40

60

80

100

120

140

MDL PQL 7.57 9.51 9.74 10.04 10.05 10.31 11.02

Met

als

Con

cent

ratio

n (u

g/L)

pH

pH vs Total Metals

Zn Se Ni Mb Cu Co Al


Figure 7.6 Total Metals – Regulated (NPDES) Concentrations (for VWRF) for Different

pH Conditions

Dissolved metal concentrations for the different pH values are shown in Figure 7.7. Most copper samples meet NPDES requirements (except pH 9.51 and 10.04) while all selenium and nickel samples do not meet NPDES requirements (Figures 7.8).

Figure 7.7 Dissolved Metals Removal with pH

0

5

10

15

20

25

30

7.57 9.51 9.74 10.04 10.05 10.31 11.02

Met

als

Con

cent

ratio

n (u

g/L)

pH

pH vs Total Metals (VWRF)

Cu Ni Se

Cu Limit (VWRF) Ni Limit (VWRF) Se Limit (VWRF)

020406080

100120140

MDL PQL 7.57 9.51 9.74 10.04 10.05 10.31 11.02

Met

als

Con

cent

ratio

n (u

g/L)

pH

pH vs Dissolved Metals

Zn Se Ni Mb Cu Co Al


Figure 7.8 Dissolved Metals – Regulated (NPDES) Concentrations (for VWRF) for

Different pH Conditions

The metals did not show the type of consistent removal with pH as was expected based upon theoretical knowledge. Figure 7.9 shows the theoretical metals solubility curves with the actual dissolve metals concentrations superimposed. The reasons for this outcome are unclear, but are assumed to be based upon the complex chemical nature of the RO concentrates.

0

5

10

15

20

25

30

7.57 9.51 9.74 10.04 10.05 10.31 11.02

Met

als

Con

cent

ratio

n (u

g/L)

pH

pH vs Dissolved Metals (VWRF)

Cu Ni Se

Cu Limit (VWRF) Ni Limit (VWRF) Se Limit (VWRF)


Figure 7.9 Zinc, Nickel, and Copper Solubility Curve (http://www.porexfiltration.com/learning-center/technology/precipitation-microfiltration/)

7.4.3 Ammonia

All ammonia values were below the permit limits for the VWRF (1.07 mg/L in the summer and 1.3 mg/L in the winter) The PQL for the test procedure was 0.1, so these results have a high level of confidence. The ammonia trends (Figure 7.10) suggests increasing as pH increases, which is understandable based upon ammonia speciation.

Zinc

Nickel

Copper


Figure 7.10 Ammonia Concentrations at Different pH Values

7.4.4 Toxicity

For the purposes of toxicity testing, the dilution value represents the amount of RO concentrate in the test container. The remaining water, for this analysis, is lab grade water. No WWTP effluent was used within these tests as the "remaining water". WWTP effluent is sometimes used in other tests to simulate the combined discharge of RO concentrate and WWTP effluent, the sum of which is required to meet the toxicity requirement. To avoid any unknown compounding of toxicity effects, it was decided to only use RO concentrate and lab water for the tests. Dilutions were adjusted to realistically portray the combined discharge for a future project. At the time of testing, the assumption was that the blending may range from ~50 percent to no blending (100 percent).

7.4.4.1 Thalassiosira pseudonana - Brackish Water Bay Discharge

As mentioned in the NPDES permit limit section, the South San Francisco Bay location is required to test toxicity of Thalassiosira pseudonana based upon the growth of the algae. This is measured by algal density (cells/mL x 106). The test passes if it can be shown that increasing the amount of RO concentrate in the water does not hinder growth. The goal NOEC is 100 percent effluent. This test assumes that the RO concentrate will be mixed with WWTP effluent before discharge, which is why the highest percentage of RO concentrate in the toxicity test is 40 percent. A passing test with this assumption is an NOEC of 40 percent or greater.

The RO concentrate, treated and untreated, was tested at five dilution levels, 8 percent, 16 percent, 24 percent, 32 percent, and 40 percent. Figure 7.11 shows the raw toxicity data, with the dilution vs algal growth. The baseline level represents the average growth of the organism not exposed to RO concentrate. To demonstrate nontoxicity, a sample must

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

7.53 9.53 9.97 10.79

Amm

onia

(mg/

L as

N)

pH


have growth at or above that level. A value below the baseline represents an "observed effect," in this case, reduced growth.

The algal growth test is conducted by first blending the lab grade water with the RO concentrate to the desired dilutions. Artificial sea salt is then added to this blend in order raise the salinity to 30 parts per thousand (ppt). At times, the artificial sea salt itself can be the cause of toxicity.

The untreated RO concentrate showed a decline in growth as the percentage of concentrate increased. The NOEC for this sample was reported as 32 percent, with higher concentrations demonstrating toxicity problems. The sample treated to pH 9.8 (sample 5.1) showed marginally reduced growth for the 8 percent, 16 percent, and 32 percent concentrations, but arguably close to the baseline growth performance. Sample 6.1, the RO concentrate treated to pH 10.96, showed an increase in algal growth as the percentage of concentrate increased and with all results showing improved growth and no toxicity. Judging from the trend, that the 100 percent RO concentrate would not reduce growth either.

Figure 7.11 Thalassiosira Pseudonana Toxicity at Different pH and Dilution Values

From these results, it is possible to conclude that pH adjustment is a successful method of decreasing toxicity. Furthermore, it can be seen that adjusting the pH to higher levels (Sample 6.1) can even increase T. pseudonana growth. This could be explained by saying that higher pH adjustment may have removed potential sources of toxicity to the algae, leaving behind nutrients and other beneficial constituents that allowed for increased growth.

0

1

2

3

4

5

6

0% 5% 10% 15% 20% 25% 30% 35% 40%

Mea

n Al

gal C

ell D

ensi

ty (c

ells

/mL

x 10

^6)

% RO Concentrate

Control (pH = 7.53)

Test 5.1 (pH = 9.8)

Test 6.1 (pH=10.96)

Baseline

No Impact Zone

Impact Zone


7.4.4.2 Ceriodaphnia dubia - Freshwater Discharge

NPDES permit compliance for the VWRF SCRE discharge is based upon Selenastrum capricornutum, with results presented below. However, often for freshwater discharge, the test species is can be the water flea, Ceriodaphnia dubia. Toxicity compliance is dependent upon reproduction effects. In order to pass, the reproduction levels of the C. dubia must not be lower than those in lab water by a statistically significant amount.

Figure 7.12 shows the C. dubia reproduction as a function of percentage of RO concentrate. Reproduction decreases in general as percentage of effluent increases (as compared to the baseline shown). For this toxicity test, a salinity control was run in parallel to determine if any adverse effects were caused by the increasing salinity. For reference, C. dubia is normally grown in cultures with a conductivity of about 300 uS/cm. The conductivity of the RO concentrate samples was near 10,000 uS/cm.

As shown in Figure 7.12, the salinity control follows very similar trends as the treated and untreated RO concentrate, though the RO concentrate repeatedly has less toxicity than the salinity control sample. Therefore, it can be stated that much, if not all, of the toxicity of the samples is due to salinity.

Figure 7.12 Ceriodaphnia Dubia Reproduction at Different pH and Dilution Values

No Impact Zone

Impact Zone


7.4.4.3 Selenastrum capricornutum - Estuary Discharge

As stated previously, the VWRF SCRE chronic toxicity is based upon Selenastrum capricornutum, a green algae. For this particular test, no salinity control was used during the initial test, but one was added and data normalized for inclusion here. For both tested conditions, the addition of RO concentrate resulted in increased toxicity (Figure 7.13). However, the salinity control suggests that a large component of the toxicity is based upon salt.

Figure 7.13 S. Capricornutum Algal Growth at Different pH and Dilution Values

7.4.4.4 Topsmelt - Ocean Discharge

As discussed previously, the toxicity compliance organism for a potential Calleguas SMP discharge (pertaining to the VWRF) is topsmelt. Earlier untreated RO concentrate testing on topsmelt was conducted in October 2015 and December 2015 using only a 100 percent dilution. The results are included within this report for comparison. As shown in Figure 7.14, the survival rate of untreated ROC is much lower than that of either test sample, and the treated RO concentrate has essentially 100 percent survival, easily surpassing the target of 25 percent reduction or less.

No Impact Zone

Impact Zone


Figure 7.14 Topsmelt Survival rates at various pH values

7.5 Conclusions

Simply put, the elevation of pH (using NaOH, but creating similar results as a lime process) for the removal of calcium, magnesium, metals, and toxicity had promising results, but requires further study and replication.

7.5.1 Metals

While zinc, calcium, magnesium, and aluminum were removed through the increase in pH, the target metals of copper and nickel were not reduced, and neither was selenium. Reasons for this difference in performance is speculation at this point, but low concentrations (such as copper) or effects from the complex nature of RO concentrate may have impacted performance. The literature provides some perspective:

• R.W. Peters, K. Young, D. Bhattacharya. Evaluation of recent treatment techniques for removal of heavy metals from industrial wastewaters. AICHE Symp. Ser., 81 (1985), pp. 1605–1703:

− Copper, iron, nickel, chromium, and lead can be removed from wastewater through precipitation using a hydroxide. Precipitation of copper and iron can be enhanced using a sulfate or sulfide. - Sheffield, (138).

− "Removal of metals hydroxide precipitation of mixed metal wastes may not be effective because the minimum solubilities for different metals occur at different pH conditions".

− "The presence of complexing agents may have an adverse effect on metal removal".

0%

20%

40%

60%

80%

100%

120%

0% 20% 40% 60% 80% 100%

Surv

ival

Per

cent

age

Dilution Value

Untreated ROC - Oct 2015

Test 5.1 (pH = 9.8)

Test 6.1 (pH = 10.96)

Baseline

Untreated ROC - Dec 2015

No Impact Zone

Impact Zone


Future testing of RO concentrate should include the following additions to previously described efforts:

1. Use of ferrous sulfide ahead of pH adjustment to improve copper and nickel removal.

2. Use of zero valent iron ahead of pH adjustment to improve selenium removal.

3. Consider other technologies such as electrocoagulation for removal of metals and selenium.

7.5.2 Toxicity

For salt tolerant organisms, the treated RO concentrate either had no toxicological effect or an improved toxicological effect, clearly suggesting that a high pH treatment improves water quality. For salt impacted organisms, the treated RO concentrate has a negative toxicological effect, but that effect appears closely tied to salt impacts. Again, this finding suggests that a high pH treatment improves water quality.

7.5.3 Implications to Ventura

For a SCRE discharge, the high pH treatment reduces toxicity (Ceriodaphnia dubia and Selenastrum capricornutum), but general toxicity from salt still exists, making an RO concentrate discharge, even with >50 percent dilution, unpermitable. The lack of removal of ammonia, copper, nickel, and selenium are not as troubling, as additional treatment (as detailed above) shows promise for improved removal. Because of the salt impacts on toxicity, RO concentrate discharge to the SCRE is not recommended.

For a potential ocean discharge (Calleguas SMP), the concentrations of metals, selenium, and other constituents in the RO concentrate are well below an ocean discharge requirement without treatment. High pH treatment was successful in eliminating RO concentrate toxicity (topsmelt), meeting the potential toxicity requirements for ocean discharge.

For RO concentrate disposal, unless salt toxicity for a SCRE discharge can be mitigated or permitted, the recommended approach is to use an ocean discharge and treat the RO concentrate to eliminate toxicity using a high pH or other proven method.

8.0 DEMONSTRATION OF INNOVATIVE UV ADVANCED OXIDATION SYSTEM

This section details a proof of concept study, demonstrating the use of an electrode technology to generate radical chemistry as part of UV AOP. This project was funded entirely by the equipment supplier (Neptune Benson). Data replication and long term performance demonstration was not in the scope or budget for this proof of concept study.


Demonstration of UV AOP performance of the Neptune Benson reactor, in accordance with DDW regulations (CDPH, 2014) was performed using H2O2 addition and using a novel component, an electrode system that generates hydroxyl radicals in-situ. The results are presented below. The standard oxidant used for UV AOP, H2O2, has a number of drawbacks, including:

• H2O2 does not absorb UV light well, with only 5 to 10 percent of the chemical actually being consumed in the AOP process. The unused chemical may require quenching agents.

• The H2O2 consumes or “scavenges” the useful hydroxyl radicals, which is detrimental to the efficacy of the overall AOP.

• The H2O2 degrades over time, is expensive to deliver (many truck trips) and is another hazardous chemical that operators would prefer not to handle.

The electrode concept is not new, as it is used for onsite chlorine generation since the 1980s. The electrode used for this project was developed from anode and cathode materials originally refined and designed as a fuel cell, and consists of a base titanium plate coated with different and proprietary elements. The anode and cathode are assembled and inserted into the access hatch immediately upstream of the UV lamp assembly. RO permeate, or water that contains very low levels of TDS will be electrolyzed to produce the hydroxyl radical for advanced oxidation. In the process there will be formation of hydrogen. The hydrogen is moist, so care must be taken to safely vent the gas to atmosphere. The end value of this innovation is clear, the ability to perform UV AOP without the use of H2O2.

For the demonstration work, the first installed UV system from Neptune Benson was providing a UV dose well in excess of the 800+ mJ/cm2 target. The research work conducted here needed a lower dose system (in the range of 500 to 800) so that proper NDMA and 1,4-dioxane dose/response analysis could be conducted. To that end, a smaller UV system was installed, replacing the larger system (Figure 8.1). Photos of the electrode system are presented in Figure 8.2.


Figure 8.1 UV Reactors (Big and Small)

Small UV Reactor for 1,4-dioxane testing

Large UV reactor (used for long-term demonstration)


Figure 8.2 Electrodes (Removed From the Pressure Vessel Ahead of the UV Reactor)

What follows below is first a review of NDMA destruction with the UV reactor, without oxidant addition and with the electrodes off. The NDMA destruction provides insight on UV dose delivery, allowing the team to fine tune the proper flowrate for 1,4-dioxane destruction testing. The 1,4-dioxane destruction was done with the electrode only, with the electrode and UV, and with the H2O2 and UV, over a range of flow.

8.1 NDMA

NDMA is assigned a Notification Level (NL) of 10 ng/L due to its carcinogenic properties. High dose UV systems following RO are commonly used for NDMA destruction. UV doses in the range of 800 mJ/cm2 to 1200 mJ/cm2 are commonly used.

The first experiments with the new UV reactor examined the RO permeate NDMA concentrations and the subsequent NDMA concentrations after UV, with results presented in Figure 8.3. These results were based upon the UV system processing 11.3 gpm, with the UV reactor power varied from 100 percent to 50 percent. These results show consistent NDMA destruction, but no measurable impact of power variation.


Figure 8.3 RO Permeate and UV Effluent NDMA Concentrations

UV is proven to destroy NDMA through photolysis, with 90 percent removal based upon a UV dose of ~900 mJ/cm2 (Sharpless and Linden, 2003). Using that log reduction correlation, the tested UV system delivered a dose ranging from ~200 to >500 mJ/cm2.

As stated above, the goal for this demonstration effort was not to provide such a high dose to destroy NDMA to the detection level, it was to run the UV system at dose ranges that allow for 1,4-dioxane dose/response quantification. To that end, the NDMA data captured above was a success.

8.2 1,4-Dioxane

DDW (CDPH, 2014) requires all IPR groundwater recharge facilities to provide, at a minimum, 0.5-log removal of 1,4-dioxane after the RO process. Destruction of 1,4-dioxane is a surrogate for broader removal of trace pollutants, as demonstrated by Hokanson et al. (2011), with Hokanson's graphic provide previously in Figure 8.4.


Figure 8.4 Destruction of Trace Pollutants by UV AOP (from Hokanson et al., 2011)

For any potable water reuse project in Ventura, IPR or DPR, RO will be a component of treatment and the RO permeate will be further treated through UV AOP with a treatment target of 0.5-log removal of 1,4 dioxane.

Flow rates of 3, 5, and 7 gpm were tested for 1,4-dioxane removal with 100 percent UV power (Figure 8.5). The electrode was compared to UV/H2O2 at two doses for the destruction of 1,4-dioxane. The 1,4-dioxane was seeded into the head of the UV reactor. The results from this study suggest:

• With the electrodes on and with the UV system off, limited destruction of 1,4-dioxane was documented. There is an apparent downward trend in destruction with an increase in flow.

• With the electrodes and UV system on, the coupled UV AOP process destroys 1,4-dioxane at or above the regulated level (0.5-log) for all tests. As flow increases, the 1,4-dioxane destruction decreases.

• With the electrodes off and with the UV system on with H2O2 dosing of 4 and 6 mg/L, UV AOP process destroys 1,4-dioxane at or above the regulated level (0.5-log) for all tests.


Figure 8.5 Destruction of 1,4-dioxane by UV AOP

8.3 Conclusions

Within the limits of this study, the electrode UV system demonstrated the ability to perform advanced oxidation and meet the DDW (CDPH, 2014) requirements for a minimum 0.5-log reduction of 1,4-dioxane. As shown by Hokanson et al. (2011), more than 0.5-log removal of a broad range of pollutants would also result under similar operating conditions. This electrode UV technology shows promise for UV AOP without chemical addition (H2O2 or NaOCl).

9.0 DEMONSTRATION OF TREATMENT SATISFYING DDW REQUIREMENTS FOR POTABLE REUSE

As demonstrated in the previous sections, each core treatment process provided either pathogen removal or pollutant removal, or a combination of pathogen and pollutant removal. The final water quality meets the standards from DDW for IPR (CDPH, 2014), as detailed below.

9.1 Pathogen Concentrations and Removal

Water treatment regulations for pathogens are predicated on reducing the risk of infection to minimal levels. For this project, the team has targeted the concentration end goals for pathogens that correspond to a modeled, annual risk of infection of 1 in 10,000 or less


(Trussell et al., 2013). DDW used this risk level to develop their pathogen criteria (CDPH, 2014) and NWRI used this risk level to develop their pathogen criteria (NWRI, 2013). Recognizing that injection is not the same as disease (infection does not necessarily lead to disease) and recognizing that potable water systems have similar risk reduction goals, the use of a 1 in 10,000 number as a minimum level of performance is reasonable. This risk level corresponds to the following potable water concentrations:

• Enteric virus - 2.22E-07 MPN/L

• Giardia - 6.80E-06 cysts/L

• Cryptosporidium - 3.00E-05 oocysts/L

There are two ways to use this information. The first approach is to measure the concentration of these pathogens in the effluent of the WWTP process and to add purification treatment processes (e.g., UF, RO, UV) that provide the necessary log reduction of those pathogens, resulting in the listed concentrations (or less). This is the approach utilized for potable water reuse projects in Texas. The second approach is to follow the State of California's 12/10/10 approach, which assumes a high concentration of pathogens in raw wastewater and requires 12-log virus removal, 10-log Giardia removal, and 10-log Cryptosporidium removal through the entire treatment train, including the WWTP. Comparisons of these two approaches indicate that the California approach is more conservative than the Texas approach, though both approaches are protective of public health.

9.1.1 Filtered Secondary Effluent Pathogen Levels

Filtered secondary effluent was sampled for protozoa, and virus on two different dates.

Giardia and Cryptosporidium results were zero counts per L on both events (<1/L). The zero counts per liter can be used to determine the subsequent log reduction necessary to attain the target potable water concentrations of 6.8E-06 and 3.0E-05 cysts and oocysts per liter, respectively for Giardia and Cryptosporidium. Using a number of 1 per Liter, 5.2 log and 4.5 log reduction is needed through subsequent treatment for Giardia and Cryptosporidium, respectively.

For the virus work these results include one cell culture (the Total Culturable Virus) and four qPCR tests (enteric virus and three norovirus tests), with results shown in the figure below. The norovirus G1A concentrations are the highest in both sampling events, while the total culturable virus (two samples) and the enteric virus (one of two samples) are the lowest in value. A simplistic and conservative approach would be to assume that each gene copy (GC) is infectious. The highest gene copy count is 38,000 GC/L for Norovirus G1A. Referring back to the target enteric virus concentration of 2.22E-07 MPN/L, 11.2 log removal of virus is needed through subsequent treatment for virus. Another approach would be to use the culturable virus data which is much lower than the gene copy data (by


several orders of magnitude). However, while we recognize that not all gene copy data represents viable organism, there remains insufficient information within the industry to make a proper correlation. Accordingly, gene copy data is used and is recognized as conservative.

Figure 9.1 Virus Concentrations in Filtered Secondary Effluent

9.1.2 Subsequent Disinfection of Filtered Secondary Effluent to Meet Potable Water Pathogen Standards

The limited pathogen data collected documents a need for a maximum of 11.2 log removal of virus, 5.2 log removal of Giardia, and 4.5 log removal of Cryptosporidium, all done by treatment processes following the media filtration and prior to potable water consumption. This project, and the relevant literature referenced within this project, documents 13+ log reduction of pathogens through the advanced processes (Table 9.1), surpassing the pathogen targets by several orders of magnitude. These log removal credits also meet the 12/10/10 targets from DDW (CDPH, 2014), recognizing that those DDW credits also allow for pathogen removal through the primary and secondary process (1 to 2-log), which is not detailed in the table below.


Table 9.1 Pathogen Removal Through Purification Processes VenturaWaterPure Direct Potable Water Reuse Demonstration Project Water Research Foundation

Log

Removal Virus

Log Removal Giardia

Log Removal Crypto

Notes

Pasteurization 5+ 3.8+ 3.8+

Pasteurization operating at a

temperature of 162 degrees F or above

Ultrafiltration 0 4 4

Pressure decay tests consistently

document membrane integrity and 4+ log removal

of protozoa

Reverse Osmosis 3+ 3+ 3+

Online monitoring with fluorescent dye

(Trasar) demonstrations reliable removal

UV Advanced Oxidation 6+ 6+ 6+

UV dose necessary for 0.5 LRV of 1,4-

dioxane far exceeds dose needed for log

reduction credits

ESB with Free Chlorination 4 0.5 0

Based upon 30 minutes of contact

time and 1 mg/L free chlorine residual

Totals 18+

(13+ without pasteurization)

17.3+ (13.5+ without pasteurization)

16.8+ (13+ without

pasteurization)

9.1.3 Finished Water (UF/RO/UV AOP and pasteurization/UF/RO/UV AOP)

As part of a broader documentation of water quality, 7 different samples were collected over the duration of the demonstration testing, with sampling for Giardia, Cryptosporidium, on a monthly basis (with some deviation) for Giardia, Cryptosporidium, total culturable virus (TCV), and legionella virus, and bacteria. All results were below detection; Giardia and Cryptosporidium were zero counts per liter, TCV counts of ~<0.003 MPN/L, and legionella counts <0.03 cfu/mL.


9.2 Chemical Pollutant Concentrations and Removal Water quality for potable water reuse is set by the CA DDW (CDPH, 2014), including criteria for TN, TOC, regulated contaminants (MCLs), contaminants with secondary MCLs, chemicals with notification levels (NLs), lead and copper, NDMA, 1,4-dioxane, NDMA, and various CECs. For this demonstration project, our team collected to demonstrate the high purity of the water, as detailed in the sections below.

9.2.1 Filtered Secondary Effluent For perspective, we include here limited sampling for CECs in the secondary effluent (Table 9.2). These results do show a number of CEC detections, but none exceed levels that may be associated with human health concerns.

Table 9.2 CEC Concentrations in Secondary Effluent and Relevant Human Health Criteria VenturaWaterPure Direct Potable Water Reuse Demonstration Project Water Research Foundation

Chemical/Compound Human Health

Criteria, ng/L

Results, ng/L

MRL, ng/L

17α-Ethinyl Estradiol 1.5 (4)

270(1,2,4) ND 1

17β-Estradiol 1(1,2) 93(4)

175(4)

ND 1

Acetaminophen 175,000(4)

350,000(1,2) ND 20

Amoxicillin 1500(6) ND 10

Atorvastain (Lipitor) 500(4) 19,000(6)

ND 1

Azithromycin 3900(4) 330 10

Bifenthrin

ND 2

Bisphenol A 35,000(1,2)

200,000(4) 1,800,000(6)

87 1

Caffeine 350,000(4) 20 1




Criteria, ng/L

Results, ng/L

MRL, ng/L

Carbamazepine 1000(6) 12,000(6)

100,000(4)

180 20

Chlorpyrifos 10,000(6)

30,000(6) ND 10

Ciprofloxacin 250,000(4) 7.6 5

Diclofenac 1800(4) 2,300,000(6)

140 1

Fipronil

190 2

Galaxolide 1,800,000(4) 3800 200

Gemfibrozil 45,000(6) 600,000(4)

210 1

Ibuprofen 400,000(4) 17 1

Iopromide (Iodinated Contrast Media)

750,000(4) 8.1 5

Meprobamate 200,000(3)

260,000(6)

730 20

N,N-Diethyl-m-toluamide (DEET) 2500(1,2)

200,000(3)

450 20

Nonylphenol & Nonylphenol Polyethoxylates

500,000(4) 1,800,000(6)

4-Nonylphenol

ND 25

Nonylphenol Diethoxylate

150 100

Nonylphenol Monoethoxylate

ND 50

Nonylphenol polyethoxylates

Octylphenol & Octylphenol Polyethoxylates

50,000(4) 5,300,000(6)

ND 25

4-tert-Octylphenol

ND 5

4-n-Octylphenol diethoxylate

48 25




Criteria, ng/L

Results, ng/L

MRL, ng/L

4-n-Octylphenol monoethoxylate ND 25

Polybrominated Diphenyl Ethers

BDE-47 ND 5

BDE-100 ND 5

BDE-153 ND 5

BDE-154 ND 5

Perfluorooctane Sulfonate (PFOS) 200(6) 500(6)

28 5

Permethrin 1000(4) ND 5

cis-Permethrin ND 2

Salicylic acid 105,000(4) 120 50

Sulfamethoxazole 35,000(4) 440,000(6)

18,000,000(6)

1200 20

TCEP, TCPP and TDCPP

TCEP 1000(4)

2100(5)

2500(1,2)

5000(3) 77,000(6)

450 20

TCPP 1700 20

TDCPP 680 20




Criteria, ng/L

Results, ng/L

MRL, ng/L

Triclosan 350(4) 2,600,000(6)

21 2

Notes: (1) 2013 Amended Recycled Water Policy for both surface spreading and groundwater injection

projects. (2) Additional health-based screening levels from 2010 SWRCB Recycled Water CEC Science

Advisory Panel Final Report. (3) NWRI 2015. Framework for Direct Potable Reuse (4) 2008 Australian Water Recycling Guidelines. (5) NRC 2012. (6) WRRF 11-02. Potable Reuse: State of the Science Report and Equivalency Criteria for

Treatment Trains (2015)

9.2.2 RO Concentrate

Another way to look at the concentrations of pollutants in wastewater is by sampling the RO concentrate, which by nature concentrates the pollutants by 5 to 7 times for many pollutants.

9.2.3 TOC Removal by RO TOC in the RO permeate was measured a total of 10 times in the laboratory, with 9 values indicating <0.5 mg/L and a 10th sample indicating 0.6 mg/L. No online TOC values were collected as part of this demonstration effort. These TOC numbers are higher than typically seen in potable water reuse RO facilities. Though speculative, we anticipate that online meters would provide greater accuracy and typically result in TOC values much lower than 0.5 mg/L. The high virus removal (6-log), high EC reduction, and the low CEC results all suggest that the RO membranes were functioning well at the demonstration facility.

9.2.4 TDS and EC Removal by RO While RO has critical roles in the removal of pathogens, organics, and trace level pollutants, RO also plays an important role in salt reduction. Over the duration of testing, the removal of salt (total dissolved solids (TDS)) and the reduction in electrical conductivity (EC) was measured across the RO membranes. Figure 9.2 is a plot of EC concentrations ahead of UF, after UF, and after RO (first stage RO, second stage RO, and combined RO permeate). This EC data tells us several things:


• The first stage of the RO system performed very well over the duration of the demonstration testing. Initial difficulties with second stage RO fouling led to poor EC reduction, corrected by replacing the second stage RO membranes and changing the chemical feed system to minimize RO fouling (as detailed previously).

• EC dropped from ~2,400 uS/cm in the RO feed to ~70 uS/cm in the combined RO permeate, a reduction of 1.6, which is consistent with the overall industry expectations.

• TDS dropped from ~1,600 mg/L in the RO feed to <50 mg/L in the combined RO permeate, again a reduction of 1.6, which is consistent with the overall industry expectations.

EC is readily monitored online and can be used as a surrogate for TDS estimation. Figure 9.3 is a plot of both EC and TDS values, suggesting a ratio of 1.5 to 1 for EC to TDS.

Figure 9.2 EC Values across UF and RO


Figure 9.3 Comparison of EC and TDS Values

9.2.5 Purified Water

The following water quality results all represent the finished water after UF, RO, and UV AOP. As many as ten sample events were used to document the high quality purified water.

9.2.5.1 MCLs Inorganic constituents with primary MCLs are shown in Table 9.3, below. This specific list is from the California DDW Table 64431-A (DDW, 2015). Of all the samples tested, only total nitrogen (TN) was detectable, and at levels well below the MCL.

Radionuclides with primary MCLs are shown in Table 9.4, below. This specific list is from the California DDW Tables 64442 and 64443 (DDW, 2015). All measured radionuclides were below the MCL. Note that Table 9.4 also includes Radium 226 and 228 listed separately, in addition to the combined Radium 226 and 228 which is regulated.

Synthetic organic chemicals, from California DDW Table 64444-A (DDW, 2015) are summarized in Table 9.5 and Table 9.6. All synthetic organic chemicals were below the detection limit.

Regulated disinfection byproducts, as defined by DDW (Table 64533-A, DDW (2015)), are summarized in Table 9.7. For the sampled DBPs, only tri-halomethanes were detected, and these were detected at levels far below the MCL values.


Table 9.3 UF/RO/UV AOP Finished Water Quality for MCLs- Inorganic Chemicals per Table 64431-A and Table 64432-A (DDW, 2015) VenturaWaterPure Direct Potable Water Reuse Demonstration Project Water Research Foundation

Constituent Unit Test 1 Test 2 Test 3 Test 4 Test 5 Test 6 Test 7 Test 8 Test 9 Test 10 MCL/Action

Level MRL

(units shown at far left) 10/29/15 11/5/15 11/12/15 11/19/15 12/17/15 2/18/16 3/3/16 3/9/16 3/23/16 3/30/16 Aluminum ug/L ND ND ND ND ND ND ND ND ND ND 200 10

Antimony ug/L ND ND ND ND ND ND ND ND ND ND 6 1

Arsenic ug/L ND ND ND ND ND ND ND ND ND ND 10 2

Asbestos MFL(1) ND ND ND ND ND ND ND ND ND ND 7 0.2

Barium ug/L ND ND ND ND ND ND ND ND 0.3 0.9 1000 0.2

Beryllium ug/L ND ND ND ND ND ND ND ND ND ND 4 1

Cadmium ug/L ND ND ND ND ND ND ND ND ND ND 5 0.2

Chromium ug/L ND ND ND ND ND ND ND ND ND ND 50 1

Copper ug/L ND ND ND ND ND ND ND ND ND ND 1300 (Action Level) 10

Cyanide ug/L ND<100 ND<100 ND <10 ND<10(2) ND<10 ND<5 ND<10 ND<10 ND<100 ND<10 150 5, 10 or 100(3)

Fluoride mg/L ND ND ND ND ND ND ND ND ND ND 2 0.1

Hexavalent Chromium ug/L ND ND ND ND ND ND ND ND ND ND 10 0.5

Lead ug/L ND ND ND ND ND ND ND ND ND ND 15 (Action Level) 0.5

Mercury ug/L ND ND ND ND ND ND ND ND ND ND 2 0.02

Nickel ug/L ND ND ND ND ND ND ND ND ND ND 100 1

Nitrate (as NO3)(4) mg/L 3.6 4.5 2.6 3 2.9 3.3 4.1 5.3 3.6 2.7 45 0.5

Nitrite (as N) mg/L ND ND ND ND ND ND ND 0.2 ND ND 1 0.2

Perchlorate ug/L ND ND ND ND ND ND ND ND ND ND 6 2

Nitrate + Nitrite (as N) mg/L 0.8 1 0.6 0.7 0.6 0.8 0.9 1.4 0.8 0.6 10 0.1

Selenium ug/L ND ND ND ND ND ND 1 ND ND ND 50 1

Thallium ND ND ND ND ND ND ND ND ND ND ND 2 0.2

Notes: (1) MFL = million fibers per liter longer than 10 um. (2) Date = 11/23/15. (3) MRL varies between tests. Refer to specific test for correct MRL. (4) Secondary effluent nitrate concentrations are typically ~8 mg/L as N (35 mg/L as NO3), suggesting ~90% removal by RO.


Table 9.4 UF/RO/UV AOP Finished Water Quality for MCLs- Radionuclides per Table 64442 AND 64443 (DDW, 2015) VenturaWaterPure Direct Potable Water Reuse Demonstration Project Water Research Foundation

Constituent Unit Test 1 Test 2 Test 3 Test 4 Test 5 Test 6 Test 7 Test 8 Test 9 Test 10 MCL MRL (units shown at

far left) 10/29/15 11/5/15 11/12/15 11/19/15 12/17/15 2/18/16 3/3/16 3/9/16 3/23/16 3/30/16

Gross Alpha (including Radium-226 but not Radon and Uranium)

pCi/L 1.01 2.41 0.824 3.22 2.13 1.56 0.993 3.82 0.189 1.68 15 2.0 - 2.5

Radium-226 pCi/L 0.132 0.042 0 0 0 0 0.076 0 0.113 0 - 0.31 - 0.65

Radium-228 pCi/L 0.001 0 0.192 0 0 0 0 0 0.001 0.069 - 0.56 - 0.78

Combined Radium-226 and Radium-228 (226 + 228)

pCi/L 0.133 0.042 0.192 0 0 0 0.076 0 0.114 0.069 5 -

Strontium 90 pCi/L 0 0 0 0 0 0 0.303 0.242 0.264 0 8 0.682

Uranium pCi/L 0 0 0.162 0 0 0.12 0 0.104 0.413 0 20 1

Tritium pCi/L 135 0 186 52.7 31.6 0 40.4 0 96.5 204 20,000 434

Beta/Photon emitters (gross beta tested)

pCi/L ND 1.8 ND 0.747 1.79 1.45 1.06 1.02 0.95 0.724 4 1.6, 1.7


Table 9.5 UF/RO/UV AOP Finished Water Quality for MCLs- Synthetic Organic Chemicals - SVOCS per Table 64444-A (DDW, 2015) VenturaWaterPure Direct Potable Water Reuse Demonstration Project Water Research Foundation

Constituent Unit

Test 1 Test 2 Test 3 Test 4 Test 5 Test 6 Test 7 Test 8 Test 9 Test 10 MCL/Action Level

MRL (units shown

at far left) 10/29/15 11/05/15 11/12/15 11/19/15 12/17/15 2/18/16 3/3/16 3/9/16 3/23/16 3/30/16

Alachlor mg/L ND ND ND ND ND ND ND ND ND ND 0.002 0.0002

Atrazine mg/L ND ND ND ND ND ND ND ND ND ND 0.001 0.0005

Benzo(a)pyrene mg/L ND ND ND ND ND ND ND ND ND ND 0.0002 0.0001

Carbofuran mg/L ND ND ND ND ND ND ND ND ND ND 0.04 0.005

Chlordane mg/L ND ND ND ND ND ND ND ND ND ND 0.002 0.0001

Dalapon mg/L ND ND ND ND ND ND ND ND ND ND 0.2 0.01

Dibromochloropropane mg/L ND ND ND ND ND ND ND ND ND ND 0.0002 0.00001

Dinoseb mg/L ND ND ND ND ND ND ND ND ND ND 0.007 0.001

Dioxin(2,3,7,8-TCDD) pg/L ND ND ND ND ND ND ND ND ND 3.00E-08 5.00E-09

Diquat mg/L ND ND ND ND ND ND ND ND ND ND 0.02 0.002

Di(2-ethylhexyl) adipate mg/L ND ND ND ND ND ND ND ND ND 0.4 0.005

Di(2-ethylhexyl) phthalate mg/L ND ND ND ND ND ND ND ND ND 0.006 0.003

Endothall mg/L ND ND ND ND ND ND ND ND ND ND 0.1 0.04

Endrin mg/L ND ND ND ND ND ND ND ND ND ND 0.002 0.00001

Ethylene Dibromide mg/L ND ND ND ND ND ND ND ND ND ND 0.00005 0.00002

Glyphosate mg/L ND ND ND ND ND ND ND ND ND ND 0.7 0.02

Heptachlor mg/L ND ND ND ND ND ND ND ND ND ND 0.0004 0.00001

Heptachlor epoxide mg/L ND ND ND ND ND ND ND ND ND ND 0.0002 0.00001

Hexachlorobenzene mg/L ND ND ND ND ND ND ND ND ND ND 0.001 0.00001

Hexachlorocyclopentadiene mg/L ND ND ND ND ND ND ND ND ND ND 0.05 0.0001

Lindane mg/L ND ND ND ND ND ND ND ND ND ND 0.0002 0.00005

Methoxychlor mg/L ND ND ND ND ND ND ND ND ND ND 0.04 0.0001

Oxamyl(Vydate) mg/L ND ND ND ND ND ND ND ND ND ND 0.2 0.005

Picloram mg/L ND ND ND ND ND ND ND ND ND ND 0.5 0.001

Polychlorinated Biphenyls (TOTAL)(1) mg/L ND ND ND ND ND ND ND ND ND ND 0.0005 0.0005

Pentachlorophenol mg/L ND ND ND ND ND ND ND ND ND ND 0.001 0.0002

Simazine mg/L ND ND ND ND ND ND ND ND ND ND 0.004 0.0005


Table 9.5 UF/RO/UV AOP Finished Water Quality for MCLs- Synthetic Organic Chemicals - SVOCS per Table 64444-A (DDW, 2015) VenturaWaterPure Direct Potable Water Reuse Demonstration Project Water Research Foundation

Constituent Unit


MRL (units shown

at far left) 10/29/15 11/05/15 11/12/15 11/19/15 12/17/15 2/18/16 3/3/16 3/9/16 3/23/16 3/30/16

Toxaphene mg/L ND ND ND ND ND ND ND ND ND ND 0.003 0.0005

2,4-D mg/L ND ND ND ND ND ND ND ND ND ND 0.07 0.002

2,4,5-TP Silvex mg/L ND ND ND ND ND ND ND ND ND ND 0.05 0.001

Bentazon mg/L ND ND ND ND ND ND ND ND ND ND 0.018 0.002

Molinate mg/L ND ND ND ND ND ND ND ND ND ND 0.02 0.002

Thiobencarb mg/L ND ND ND ND ND ND ND ND ND ND 0.001 0.001 Notes: (1) Polychlorinated Biphenyls (TOTAL) includes: PCB 1016, PCB 1221, PCB 1232, PCB 1242, PCB 1248, PCB 1254, and PCB 1260. Table 9.6 UF/RO/UV AOP Finished Water Quality for MCLs- Synthetic Organic Chemicals - VOCS per Table 64444-A (DDW, 2015)


Constituent Unit Test 1 Test 2 Test 3 Test 4 Test 5 Test 6 Test 7 Test 8 Test 9 Test 10 MCL/Action Level MRL

10/29/15 11/05/15 11/12/15 11/19/15 12/17/15 2/18/16 3/3/16 3/9/16 3/23/16 3/30/16 Benzene mg/L ND ND ND ND ND ND ND ND ND ND 0.001 0.0005

Carbon tetrachloride mg/L ND ND ND ND ND ND ND ND ND ND 0.0005 0.0005

cis-1,2-Dichloroethylene mg/L ND ND ND ND ND ND ND ND ND ND 0.006 0.0005

Dichloromethane mg/L ND ND ND ND ND ND ND ND ND ND 0.005 0.0005

Ethylbenzene mg/L ND ND ND ND ND ND ND ND ND ND 0.3 0.0005

Monochlorobenzene (Chlorobenzene) mg/L ND ND ND ND ND ND ND ND ND ND 0.07 0.0005

o-Dichlorobenzene mg/L ND ND ND ND ND ND ND ND ND ND 0.6 0.0005

p-Dichlorobenzene mg/L ND ND ND ND ND ND ND ND ND ND 0.005 0.0005

Styrene mg/L ND ND ND ND ND ND ND ND ND ND 0.1 0.0005

Tetrachloroethylene(PCE) mg/L ND ND ND ND ND ND ND ND ND ND 0.005 0.0005

Toluene mg/L ND ND ND ND ND ND ND ND ND ND 0.15 0.0005

trans-1,2-Dichloroethylene mg/L ND ND ND ND ND ND ND ND ND ND 0.01 0.0005

Trichloroethylene (TCE) mg/L ND ND ND ND ND ND ND ND ND ND 0.005 0.0005

Vinyl chloride mg/L ND ND ND ND ND ND ND ND ND ND 0.0005 0.0005

Xylenes (total) mg/L ND ND ND ND ND ND ND ND ND ND 1.75 0.0005


Table 9.6 UF/RO/UV AOP Finished Water Quality for MCLs- Synthetic Organic Chemicals - VOCS per Table 64444-A (DDW, 2015) VenturaWaterPure Direct Potable Water Reuse Demonstration Project Water Research Foundation

Constituent Unit Test 1 Test 2 Test 3 Test 4 Test 5 Test 6 Test 7 Test 8 Test 9 Test 10 MCL/Action Level MRL

10/29/15 11/05/15 11/12/15 11/19/15 12/17/15 2/18/16 3/3/16 3/9/16 3/23/16 3/30/16 1,1-Dichloroethylene mg/L ND ND ND ND ND ND ND ND ND ND 0.006 0.0005

1,1,1-Trichloroethane mg/L ND ND ND ND ND ND ND ND ND ND 0.2 0.0005

1,1,2-Trichloroethane mg/L ND ND ND ND ND ND ND ND ND ND 0.005 0.0005

1,2-Dichloroethane mg/L ND ND ND ND ND ND ND ND ND ND 0.0005 0.0005

1,2-Dichloropropane mg/L ND ND ND ND ND ND ND ND ND ND 0.005 0.0005

1,2,4-Trichlorobenzene mg/L ND ND ND ND ND ND ND ND ND ND 0.005 0.0005

1,1-Dichloroethane mg/L ND ND ND ND ND ND ND ND ND ND 0.005 0.0005

1,3-Dichloropropene mg/L ND ND ND ND ND ND ND ND ND ND 0.0005 0.0005

Methyl-tert-butyl ether (MTBE) mg/L ND ND ND ND ND ND ND ND ND ND 0.013 0.005 (Secondary

MCL)

0.001

1,1,2,2-Tetrachloroethane mg/L ND ND ND ND ND ND ND ND ND ND 1.2 0.0005

Trichlorofluoromethane mg/L ND ND ND ND ND ND ND ND ND ND 0.15 0.0005

1,1,2-Trichloro-1,2,2-Trifluoroethane mg/L ND ND ND ND ND ND ND ND ND ND 1.2 0.0005


Table 9.7 UF/RO/UV AOP Finished Water Quality for MCLs- Disinfection Byproducts per Table 64533-A (DDW, 2015) VenturaWaterPure Direct Potable Water Reuse Demonstration Project Water Research Foundation

Disinfection Byproduct Unit

Test 1 Dup.

Test 2 Dup.

Test 3 Dup.

Test 4 Dup.

Test 5 Dup.

Test 6 Dup.

Test 7 Dup.

Test 8 Dup.

Test 9 Dup.

Test 10 Dup.

MCL/ Action Level, mg/L

MRL, mg/L

10/29/15 11/5/15 11/12/15 11/19/15 12/17/15 2/18/16 Total Trihalomethanes (TTHM)

mg/L 0.0033 0.0054 0.0028

0.0043 0.0029 0.0044

0.003

0.0033

0.0024

0.0019

0.0013 0.0007

0.0183 0.0177

0.0012 0.0006

0.004

0.0048 0.0034

0.0051

0.08 -

Haloacetic acids (five)(HAA5)(

1)

mg/L ND ND ND ND ND ND ND ND ND ND 0.06 0.001 - 0.002

Bromate mg/L ND ND ND ND ND ND ND ND ND ND 0.01 0.005

Chlorite mg/L ND ND ND ND ND ND ND ND ND ND 1.0 0.01

Chlorate(1) mg/L 0.8* 0.01 Notes: (1) Haloacetic acids (five) includes: Bromoacetic Acid, Chloroacetic Acid, Dibromoacetic Acid, Dichloroacetic Acid and Trichloroacetic Acid.


9.2.5.2 Secondary MCLs

Constituents found in Tables 64449-A and 64449-B (DDW, 2015) for secondary MCLs were sampled after the UV AOP, so all water was subjected to UF, RO, and UV AOP. All data is shown in Tables 9.8 below. The vast majority of analysis resulted in non-detect, and the concentrations of detected constituents were well below the secondary MCLs.

9.2.5.3 NLs

Contaminants with notification levels (NLs), per DDW (2015) were sampled after the UV AOP, so all water was subjected to UF, RO, and UV AOP. All data is shown in Tables 9.9 below. No sampled contaminants exceeded a NL.

9.2.5.4 CECs

Finished water CEC data demonstrates a high quality finished water from the Ventura WaterPure demonstration facility. Thirty-three CECs were sampled over eight different events (Table 9.10). The sample location was the finished water after the UV AOP, so all water was subjected to UF, RO, and UV AOP. For the 264 samples (33*8), there were only 4 CECs detected, and three of the CECs had duplicate sampling in which the duplicate sample was below detection. The field blanks for every test condition came back below detection (field blanks not shown below). All CEC data is presented below.

9.2.5.5 Water Quality Conclusions

Without exception, the finished water quality met all regulated water quality targets and provided robust removal of trace level unregulated pollutants. Where chemicals were detected in the finished water, they were below health-based levels.


Table 9.8 UF/RO/UV AOP Finished Water Quality for Secondary MCLs per Tables 64449-A and 64449-B (DDW, 2015) VenturaWaterPure Direct Potable Water Reuse Demonstration Project Water Research Foundation

Secondary Constituent Unit Test 1 Test 2 Test 3 Test 4 Test 5 Test 6 Test 7 Test 8 Test 9 Test 10

MCL/Action Level (units shown at

far left)

MRL (units shown at

far left) 10/29/15 11/05/15 11/12/15 11/19/15 12/17/15 2/18/16 3/3/16 3/9/16 3/23/16 3/30/16

Color ACU ND ND ND ND ND ND ND ND ND ND 15 color units 5

Corrosivity (below)*: Non-corrosive

Langelier Index - 20degrees C - -3 -4.9 -2.4 5.4 -2.8 -4.5 -4.8 -4.7 -4.1 -2.1 Non-corrosive -

Langelier Index at 60 degrees C - Non-corrosive -

Aggressiveness Index-Calculated - 8.7 6.8 9.3 7.4 8.9 7.2 7 7 7.6 9.6 Non-corrosive -

pH of CaCO3 saturation(25C) units Non-corrosive 0.1

pH of CaCO3 saturation(60C) units Non-corrosive 0.1

Bicarb. Alkalinity as HCO3, calc mg/L 10 ND ND ND 10 10 10 20 10 10 Non-corrosive 10

Foaming agents (Surfactants) mg/L Negative ND Negative ND ND ND ND ND Negative Negative 0.5 0.1

pH SU 7.3 5.4 7.9 6 7.5 5.8 5.6 5.6 6.2 8.2 6.5-8.5 -

Hardness (as CaCO3) mg/L ND ND ND ND ND ND ND ND ND ND 250 -

Odor (SM 2150B - Odor at 60 C (TON))

TON ND ND 2 ND ND ND ND ND ND ND 3 (Threshold Odor Number)

1

Total dissolved solids(TDS) mg/L 20 30 30 ND 30 50 60 50 40 40 500 20

Aluminum mg/L ND ND ND ND ND ND ND ND ND ND 0.05-0.2 0.01

Chloride mg/L 5 4 4 4 4 8 9 10 10 9 250 1

Copper ug/L ND ND ND ND ND ND ND ND ND ND 1000 10

Fluoride mg/L ND ND ND ND ND ND ND ND ND ND 2 0.1

Iron mg/L ND ND ND ND 0.05 ND ND ND ND ND 0.3 0.03

Manganese mg/L ND ND ND ND ND ND ND ND ND ND 0.05 0.01

Silver mg/L ND ND ND ND ND ND ND ND ND ND 0.1 0.001

Sulfate mg/L ND ND ND ND ND 2 3 3 2 ND 250 2

Turbidity NTU ND ND ND ND 0.2 0.2 0.1 0.2 0.3 4.8 5 0.1


Table 9.8 UF/RO/UV AOP Finished Water Quality for Secondary MCLs per Tables 64449-A and 64449-B (DDW, 2015) VenturaWaterPure Direct Potable Water Reuse Demonstration Project Water Research Foundation

Secondary Constituent Unit Test 1 Test 2 Test 3 Test 4 Test 5 Test 6 Test 7 Test 8 Test 9 Test 10

MCL/Action Level (units shown at

far left)

MRL (units shown at

far left) 10/29/15 11/05/15 11/12/15 11/19/15 12/17/15 2/18/16 3/3/16 3/9/16 3/23/16 3/30/16

Specific Conductance uS/cm 50 49 42 41 44 65 66 78 68 64 900 1

Zinc mg/L ND ND ND ND ND ND ND ND ND ND 5 0.02

Table 9.9 UF/RO/UV AOP Finished Water Quality for Drinking Water NLs per DDW, 2015a


Secondary Constituent Unit


(units shown at far left) MRL

(units shown at far left) 10/29/15 11/05/15 11/12/15 11/19/15 12/17/15 2/18/16 3/3/16 3/9/16 3/23/16 3/30/16

Boron mg/L 0.4 0.5 0.4 0.4 0.4 0.5 0.6 0.5 0.6 0.5 1 0.1

n-Butylbenzene mg/L ND ND ND ND ND ND ND ND ND ND 0.26 0.0005

sec-Butylbenzene mg/L ND ND ND ND ND ND ND ND ND ND 0.26 0.0005

tert-Butylbenzene mg/L ND ND ND ND ND ND ND ND ND ND 0.26 0.0005

Carbon disulfide mg/L 0.16

Chlorate mg/L 0.8

2-Chlorotoluene mg/L ND ND ND ND ND ND ND ND ND ND 0.14 0.0005

4-Chlorotoluene mg/L ND ND ND ND ND ND ND ND ND ND 0.14 0.0005

Diazinon mg/L ND ND ND ND ND ND ND ND ND ND 0.0012 0.002

Dichlorodifluoromethane (Freon 12)

mg/L ND ND ND ND ND ND ND ND ND ND 1 0.0005

1,4-Dioxane mg/L 0.001

Ethylene glycol mg/L 14

Formaldehyde mg/L 0.1

HMX mg/L 0.35

Isopropylbenzene mg/L ND ND ND ND ND ND ND ND ND ND 0.77 0.0005

Manganese mg/L ND ND ND ND ND ND ND ND ND ND 0.5 0.01

Methyl isobutyl ketone (MIBK)

mg/L 0.12

Naphthalene mg/L ND ND ND ND ND ND ND ND ND ND 0.017 0.0005


Table 9.9 UF/RO/UV AOP Finished Water Quality for Drinking Water NLs per DDW, 2015a


Secondary Constituent Unit


(units shown at far left) MRL

(units shown at far left) 10/29/15 11/05/15 11/12/15 11/19/15 12/17/15 2/18/16 3/3/16 3/9/16 3/23/16 3/30/16

N-Nitrosodiethylamine (NDEA)

mg/L 0.00001

N-Nitrosodimethylamine (NDMA)

ng/L 2.5 2.3 ND ND ND ND ND ND ND ND 10 2

N-Nitrosodi-n-propylamine (NDPA)

mg/L 0.00001

Propachlor** mg/L ND ND ND ND ND ND ND ND ND ND 0.09 0.0005

n-Propylbenzene 0.26 mg/L ND ND ND ND ND ND ND ND ND ND 0.26 0.0005

RDX mg/L 0.0003

Tertiary butyl alcohol (TBA)

mg/L 0.012

1,2,3-Trichloropropane (1,2,3-TCP)

mg/L 0.000005

1,2,4-Trimethylbenzene mg/L ND ND ND ND ND ND ND ND ND ND 0.33 0.0005

1,3,5-Trimethylbenzene mg/L ND ND ND ND ND ND ND ND ND ND 0.33 0.0005

2,4,6-Trinitrotoluene (TNT)

mg/L 0.001

Vanadium mg/L 0.05 Notes: a. http://waterboards.ca.gov/drinking_water/certlic/drinkingwater/documents/notificationlevels/notificationlevels.pdf

http://waterboards.ca.gov/drinking_water/certlic/drinkingwater/documents/notifications


Table 9.10 UF/RO/UV AOP Finished Water Quality for CECs VenturaWaterPure Direct Potable Water Reuse Demonstration Project Water Research Foundation

Date Collected 10/21/2015 10/21/2015 11/17/2015 11/17/2015 12/1/2015 12/1/2015 12/7/2015 3/30/2016 Location Finished Finished Finished Finished Finished Finished Finished Finished

Sub Location Duplicate Duplicate Duplicate Tap Location Units UV/AOP UV/AOP UV/AOP UV/AOP UV/AOP UV/AOP UV/AOP UV/AOP

Gemfibrozil ng/L < 0.25 < 0.25 < 0.25 < 0.25 < 0.25 < 0.25 < 0.25 0.33

Naproxen ng/L < 0.50 < 0.50 < 0.50 < 0.50 < 0.50 < 0.50 < 0.50 < 0.50

Triclosan ng/L 1.6 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0

Ibuprofen ng/L < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0

Acetaminophen ng/L < 5.0 < 5.0 < 5.0 < 5.0 < 5.0 < 5.0 < 5.0 < 5.0

Sucralose ng/L < 25 < 25 < 25 < 25 < 25 < 25 < 25 < 25

Triclocarban ng/L < 2.0 < 2.0 < 2.0 < 2.0 < 2.0 < 2.0 < 2.0 < 2.0

Sulfamethoxazole ng/L < 0.25 < 0.25 < 0.25 < 0.25 < 0.25 < 0.25 < 0.25 0.32

Atenolol ng/L < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0

Trimethoprim ng/L < 0.25 < 0.25 < 0.25 < 0.25 < 0.25 < 0.25 < 0.25 0.38

Caffeine ng/L < 5.0 < 5.0 < 5.0 < 5.0 < 5.0 < 5.0 < 5.0 < 5.0

Fluoxetine ng/L < 0.50 < 0.50 < 0.50 < 0.50 < 0.50 < 0.50 < 0.50 < 0.50

Meprobamate ng/L < 0.25 < 0.25 < 0.25 < 0.25 < 0.25 < 0.25 < 0.25 < 0.25

Carbamazepine ng/L < 0.50 < 0.50 < 0.50 < 0.50 < 0.50 < 0.50 < 0.50 < 0.50

Primidone ng/L < 0.50 < 0.50 < 0.50 < 0.50 < 0.50 < 0.50 < 0.50 < 0.50

DEET ng/L < 1.0 < 1.0 < 1.0 < 1.0 1.6 < 1.0 < 1.0 < 1.0

TCEP ng/L < 10 < 10 < 10 < 10 < 10 < 10 < 10 < 10

PFBA ng/L < 5.0 < 5.0 < 5.0 < 5.0 11 < 5.0 < 5.0 < 5.0

PFHxS ng/L < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 <0.25

PFHxA ng/L < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 <0.5

PFOA ng/L < 5.0 < 5.0 < 5.0 < 5.0 < 5.0 < 5.0 < 5.0 <0.5

PFOS ng/L < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 <0.5

PFNA ng/L < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 <0.5

PFDA ng/L < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 <0.5

PFUdA ng/L < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 <0.5

PFDoA ng/L < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 <0.25

PFPnA ng/L < 2.0 < 2.0 < 2.0 < 2.0 < 2.0 < 2.0 < 2.0 <2

PFHpA ng/L < 0.50 < 0.50 < 0.50 < 0.50 < 0.50 < 0.50 < 0.50 <0.5

Estrone ng/L < 0.20 < 0.20 < 0.20 < 0.20 < 0.20 < 0.20 < 0.20 < 0.20


Table 9.10 UF/RO/UV AOP Finished Water Quality for CECs VenturaWaterPure Direct Potable Water Reuse Demonstration Project Water Research Foundation

Date Collected 10/21/2015 10/21/2015 11/17/2015 11/17/2015 12/1/2015 12/1/2015 12/7/2015 3/30/2016 Location Finished Finished Finished Finished Finished Finished Finished Finished

Sub Location Duplicate Duplicate Duplicate Tap Location Units UV/AOP UV/AOP UV/AOP UV/AOP UV/AOP UV/AOP UV/AOP UV/AOP

Estradiol ng/L < 0.50 < 0.50 < 0.50 < 0.50 < 0.50 < 0.50 < 0.50 < 0.50

Ethynylestradiol ng/L < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0

Testosterone ng/L < 0.50 < 0.50 < 0.50 < 0.50 < 0.50 < 0.50 < 0.50 < 0.50

Progesterone ng/L < 0.50 < 0.50 < 0.50 < 0.50 < 0.50 < 0.50 < 0.50 < 0.50


10.0 TOURS, EDUCATION, AND OUTREACH

Ventura Water used the demonstration facility to educate staff (engineering, operations, and maintenance), educate their community, and educate local regulators on the safety of potable water reuse. Ventura Water has developed a two-pronged approach, with web-based outreach and with weekly tours and education at the demonstration facility (see Figures 10.1, 10.2, and 10.3).

Figure 10.1 Screenshot of Detailed Website on Potable Water Reuse

(http://www.cityofventura.net/water/sustainable-water)

http://www.cityofventura.net/water/sustainable-water


Figure 10.2 VenturaWaterPure Brochure

Figure 10.3 VenturaWaterPure Tour Photo and Example Banner (Banners Shown for

Each Treatment Process at the Demonstration Facility)

10.1.1 VenturaWaterPure Tour

Prior to the tour, community members are shown a short animation (the Ways of Water, produced as part of Salveson et al., 2016), given a short presentation on the components of the demonstration facility, and given a questionnaire. The pre-tour questions asked were:

• What prompted you to come to the VenturaWaterPure demonstration facility today?

• What is your primary source of drinking water?

• How much do you feel you know about Ventura's water sources?


• How do you feel about adding recycled water to our drinking water supply?

• What concerns do you have about this water supply, if any?

The public then is led through the demonstration facility, stopping at each treatment process for a full description of performance. After the tour, the public is then asked the following post-tour questions:

• How informative was the tour today?

• Is there any additional information you think should be included in the tour?

• Having learned more about the water cycle and the treatment process, how do you feel now about the idea of adding recycled water to our drinking water supply?

• If your thinking has changed since completing the tour, what in particular changed your opinion?

• Which of the drinking water scenarios would you prefer?

• Please indicate the strength of your preference for your answer to the prior question?

• How do you feel about adding recycled water to our drinking water supply if it has received regulatory and government endorsement?

• How would you rate your confidence in Ventura Water's ability to operate this water recycling plant effectively?

• How would you rate your confidence in Ventura Water's ability to communicate when a malfunction in the operations occurs that may affect water quality?

• You are (male/female)?

• What is your ZIP code where you live?

• Which of the following best describes your age? under 18 years, 18-34 years, 35 to 54 years, 55 to 64 years, 65+ years.

• What is your level of education (i.e., BS, BA)?

10.1.2 VenturaWaterPure Survey Results

Select results suggest:

• The educational value of the demonstration facility and the overall support for potable water reuse in Ventura (Figure 10.4).

• The apparent support for either groundwater recharge, surface water augmentation, or direct supplement to the existing water supply (Figure 10.5).


• Regulatory support for potable reuse provides a large measure of confidence to the public (Figure 10.6).

Figure 10.4 Pre and Post Tour Survey of the Support for Potable Water Reuse in

Ventura

Figure 10.5 Relative Support for IPR versus DPR


Figure 10.6 Regulatory Support Translates into Public Support

10.1.3 Bren School at UCSB

In parallel with the tours and information summarized above, Ventura Water engaged the UC Santa Barbara Bren School of Environmental Science and Management to further understand public perception barriers and to engage the public on potable water reuse (UCSB, 2015).

The primary aspects of the work included: 1. A comprehensive literature review of concerns around the potable reuse process 2. Identification of community-specific concerns in Ventura through the use of surveys 3. Development of a set of recommendations and outreach criteria to address key public

concerns.

The work from the Bren School is attached to this report as Appendix A.

11.0 CONCLUSIONS This potable water reuse demonstration effort undertaken by Ventura Water, with the assistance of the Water Research Foundation, has demonstrated the reliable purification of filtered effluent from the VWRF. Key values of this work include:

Demonstration that newly purified water met all DDW standards for chemical and pathogenic pollutants.

Demonstration of innovative methods for system performance monitoring, including the use of ATP to track microbiological performance across UF and the use of Trasar to track performance across RO, both industry first demonstrations.


Demonstration of electroded UV for UV AOP applications and 1,4-dioxane destruction, an industry first demonstration.

Evaluation of pasteurization as a potential component of a potable waterreuse treatment train.

Development of system design and operational criteria, including UF flux and RO chemical use and recovery targets.

Demonstration of RO concentrate toxicity reduction through high pH treatment.

Generation of community support through targeted and transparent outreach and education campaigns.

12.0 REFERENCES Altamonte Springs, 2017. “Potable Reuse Demonstration Pilot Project Report”. Report

prepared by Carollo Engineers for the Altamonte Springs Florida. October 2017.

Australian Academy of Technological Sciences and Engineering (ATSE), (2013). “Drinking Water through Recycling: The benefits and costs of supplying direct to the distribution system”. Australian Water Recycling Centre of Excellence. Melbourne, Australia.

Baronti, C., R. Curini, G. D’Ascenzo, A. DiCoricia, A. Gentili, and R. Samper. 2000. Monitoring Natural and Synthetic Estrogens at Activated Sludge Sewage Treatment.

Bellona, C., G. Oelker, J. Luna, G. Filteau, G. Amy, and J. E. Drewes. 2008. Comparing nanofiltration and reverse osmosis for drinking water augmentation. Journal - American Water Works Association 100(9): 102-116.

Carollo Engineers, 2007. “RP&P Wastewater Pasteurization System Validation Report”. Report prepared by Carollo Engineers for the Ryan Pasteurization and Power.

Carollo Engineers, 2014a. “Testing Results of the Pasteurization Demonstration Unit at the Ventura WRF”. Report prepared by Carollo Engineers for the City of Ventura.

Carollo Engineers, 2014b. “Spot Check Bioassay Test Report for the Pasteurization System in Graton, California”. Report prepared by Carollo Engineers for the Pasteurization Technology Group.

CDPH (2014). Groundwater Replenishment Using Recycled Water (Water Recycling Criteria. Title 22, Division 4, Chapter 3, California Code of Regulations). California State Water Resources Control Board Division of Drinking Water.http://www.waterboards.ca.gov/drinking_water/certlic/drinkingwater/documents/lawbook/RWregulations_20140618.pdf Published 6/18/14. Final.

Chao, K-K, C-C Chao, and W-L Chao, 2004. Evaluation of Colilert-18 for Detection of Coliforms and Escherichia Coli in Subtropical Freshwater, Appl Environ Microbiol. 70(2): 1242-1244.

Clean Water Services. 2014. “Direct Potable Reuse Water Reuse Demonstration”. Report prepared by Carollo Engineers for Clean Water Services, Oregon.


Coxon, S., Eggleton, M. Iantosca, C., Sajor, J., Tague, N., and Dozier, J. (2015). Increasing Public Acceptance of Direct Potable Reuse Reuse as a Drinking Water Source in Ventura, California, prepared by the Bren School of Environmental Science and Management at UCSB.

DDW (2015). Title 22 Code of Regulations, Division 4, Chapter 15, "California Regulations Related to Drinking Water." July 16, 2015.

Gerringer, F.; Pecson, B.; Trussell, R.S.; Trussell, R.R. (2014) "Potable reuse equivalency criteria and treatment train evaluation." Work based upon WRRF 11-02. Presented at the 2014 WateReuse California Annual Conference, Newport Beach, California, March 16-18, 2014.

Gerba, C.P, Gramos, D.M, and Nwachukwu, N. Comparative Inactivation of Enteroviruses and Adenovirus 2 by UV Light. Appl Environ Microbiol. Oct 2002; 68(10): 5167–5169. 10.1128/AEM.68.10.5167-5169.2002.

Henderson, R. K., Baker, A., Murphy, K. R., Hambly, A., Stuetz, R. M., & Khan, S. J. (2009). Fluorescence as a potential monitoring tool for recycled water systems: A review. Water Research, 43(4), 863–881. http://doi.org/10.1016/j.watres.2008.11.027.

Hijnen, W., E. Beerendonk, and G. Medema (2006) “Inactivation credit of UV radiation for viruses, bacteria and protozoan (oo )cysts in water: A review,” Water Research, 40, 1, 3-22.

Hokanson, D.R., Trussell, R.R., Tiwari, S.K., Stolarik, G., Bazzi, A., Hinds, J., Wetterau, G., Richardson, T., Dedovic-Hammond, S. (2011) “Pilot Testing to Evaluate Advanced Oxidation Processes for Water Reuse,” Proceedings WEFTEC 2011, Los Angeles, CA, October 15-19.

Khulbe, K., Feng, C., Matsuura, T. 2008. “Synthetic Polymeric Membranes, Characterization by Atomic Force Microscopy.” Springer. Leiprig Germany. 2008.

Kim, H.-C. and B. Dempsey (2008) Effects of wastewater effluent organic materials on fouling in ultrafiltration. Water Research 42: 3379.

Kitis, M., Lozier, J.C., Kim, J.H., Mi, B., and Marinas, B.J, (2003) "Microbial Removal and Integrity Monitoring of RO and NF Membranes." AWWA, 95, 12, 105-119.

Kosutic, K. and Kunst, B. 2002. “RO and NF membrane fouling and cleaning and pore size distribution variations.” Desalination 150 (2002) 113-120.

Knoell, T., McKeever, J., and Gonzalez, R. "Optimizing Operations of the Groundwater Replenishment System: Developing WQ Profiles Using Non-Traditional Techniques." Presented at the AWWA Annual Conference & Exposition, 2015.

Linden, K., Salveson, A., Thurston, J. (2012) Study of Innovative Treatments for Reclaimed Water. Final Report for the WateReuse Research Foundation Project No. 02-009. Washington, DC.

Lovins, III, W., J. Taylor, and S. Hong. 2002. Microorganism Rejection by Membrane Systems. Environ. Eng. Sci., 19(2): 453-465.

MWH Americas (2012). California Department of Public Health Conditional Acceptance Testing for TORAY HFU-2020N Membrane-775 ft2. Prepared for TORAY Industries, Inc. by MWH Americas.

http://dx.doi.org/10.1128%2FAEM.68.10.5167-5169.2002


NRC (2012). Water Reuse: Potential for Expanding the Nation’s Water Supply through Reuse of Municipal Wastewater, National Research Council, National Academies Press, Washington, DC. http://www.nap.edu/catalog.php?record_id=13303.

NRMMC/EPHC/NHMRC (2008). Australian Guidelines for Water Recycling: Managing Health and Environmental Risks (Phase 2) -- Augmentation of Drinking Water Supplies, Australia.

NWRI (2013). Examining the Criteria for Direct Potable Reuse, a National Water Research Institute Independent Advisory Panel Final Report prepared for Trussell Technologies under WateReuse Research Foundation Project No. 11-02.

Pype, M.-L., Patureau, D., Wery, N., Poussade, Y., & Gernjak, W. (2013). Monitoring reverse osmosis performance: Conductivity versus fluorescence excitation–emission matrix (EEM). Journal of Membrane Science, 428, 205–211.

Reardon, R., F. DiGiano, M. Aitken, S. Paranjape, J. Kim, and S. Chang (2005). “Membrane Treatment of Secondary Effluent for Subsequent Use.” Water Environ. Res. Foundation Project 01-CTS-6 Final Report, Washington, DC.

Rochelle, P., Upton S., Montelone, B., and Woods, K. The response of Cryptosporidium parvum to UV Light: Trends in Parasitology. 2005. 21, 2, 81-87.

Salveson, A., J. Brown, Z. Zhou, and J. Lopez (2010) Monitoring for Microconstituents in an Advanced Wastewater Treatment Facility and Modeling Discharge of Reclaimed Water to Surface Canals for Indirect Potable Reuse, Final Report for WateReuse Research Foundation Project No. 06-019 Washington, DC.

Salveson, A., Mackey, E., Salveson, M., Flynn, M. (2014). “Application of Risk Reduction Principles to Direct Potable Reuse,” Final Report for WateReuse Research Foundation Project No. 11-10, Alexandria, VA.

Salveson, A., Steinle-Darling, E., Trussell, S., Pecson, B., Macpherson, L. (2016). “Guidelines for Engineered Storage for Direct Potable Reuse,” Final Report for WateReuse Research Foundation Project No. 12-06, Alexandria, VA.

Sanciolo, P., Monis, P., Lau, M., Blackbeard, J., Lewis, J., Salveson, A., Fontaine, N., Ryan, G., Kalika, V., Navaratna, D., Millot, G., and Gray, S. (2015). "Pasteurization for the Production of Class A Water." Australian Water Recycling Centre of Excellence Project Final Report. Produced by Victoria University, Melbourne, Australia.

Schäfer, A.I., A.G. Fane, and T.D. Waite, Eds. 2005. Nanofiltration, Principles and Applications. Elsevier.

Sedlak, D.L., and M. Kavanaugh. 2006. Removal and Destruction of NDMA and NDMA Precursors during Wastewater Treatment. WateReuse Research Foundation Project 01-002 Final Report, Alexandria, VA.

Sharpless, C. and Linden, K. (2003). Experimental and Model Comparisons of Low- and Medium-Pressure Hg Lamps for the Direct and H2O2 Assisted UV Photodegradation of N-Nitrosodimethylamine in Simulated Drinking Water. Environ. Sci. Technol (2003). 37, 1933-1940.

Snyder, S., E. Wert, H. Lei, P. Westerhoff, and Y. Yoon. 2007. Removal of EDCs and Pharmaceuticals in Drinking and Reuse Treatment Processes. Denver, CO: American Water Works Research Foundation.


Snyder, S. A., von Gunten, U., Amy, G., Debroux, J., and Gerrity, D., 2012 “Identifying Hormonally Active Compounds, Pharmaceuticals, and Personal Care Product Ingredients of Health Concern from Potential Presence in Water Intended for Indirect Potable Reuse.” WateReuse Research Foundation Product Number 08-05.

Steinle-Darling, E., E. Litwiller, and M. Reinhard. 2010. Effects of Sorption on the Rejection of Trace Organic Contaminants during Nanofiltration. Environ. Sci. Technol., 44(7): 2,592-2,598.

Tchobanoglous, G., Leverenz, H.L., Nellor, M.H. and Crook, J. (2011). Direct Potable Reuse: A Path Forward. WateReuse Research Foundation and WateReuse California, Alexandria, VA.

Tng, K.H., Currie, J., Roberts, C., Koh, S.H., Audley, M. and Leslie, G.L. (2015). Resilience of Advanced Water Treatment Plants for Potable Reuse, Australian Water Recycling Centre of Excellence, Brisbane, Australia.

Trussell, R.R., A. Salveson, S.A. Snyder, R.S. Trussell, D. Gerrity, and B. Pecson (2013). “Potable Reuse: State of the Science Report and Equivalency Criteria for Treatment Trains,” a Report for WateReuse Research Foundation Project 11-02, Alexandria, VA.

USEPA (1990). Guidance Manual for Compliance with the Filtration and Disinfection Requirements for Public water Systems Using Surface Water Sources, Office of Drinking Water, prepared by Malcolm Pirnie, Inc. and HDR Engineering, Inc. under EPA Contract no. 68-01-6989, Washington, DC.

USEPA (1998). Interim Enhanced Surface Water Treatment Rule; 40 CFR Parts 141 and 142; Federal Register, Cincinnati OH, 63 (241), 69.477–69.521.

USEPA (2006a). Stage 2 Disinfectant and Disinfection Byproduct Rule 71 CFR page 388, Federal Register, January 4.

USEPA (2006b). Long Term 2 Enhanced Surface Water Treatment Rule (Final Rule). 40 CFR Part 9, 141, and 142.

USEPA (2006c). “Ultraviolet Disinfection Guidance Manual for the Final Long Term 2 Enhanced Surface Water Treatment Rule,” EPA Office of Water (4601), EPA 815-R-06-007, June 2006, Washington, DC.

USEPA (2010). “Water Research Foundation (WRF), Challenge Organisms for Inactivation of Viruses by Ultraviolet Treatment.” 2010.

Ventura Water, 2014. “Testing Results of the Pasteurization Demonstration Unit at the Ventura WRF”. Report prepared by Carollo Engineers for Ventura Water California. 2014.

WRD (2013). “Amended Title 22 Engineering Report for the Leo. J. Vander Lans Water Treatment Facility Expansion: Alamitos Barrier Recycled Water Project. Final.”

DIRECT POTABLE WATER REUSE DEMONSTRATION PROJEC

APPENDIX A - BREN SCHOOL REPORT

Increasing Public Acceptance of Direct Potable Reuse as a Drinking Water Source in Ventura, California A Group Project submitted in partial satisfaction of the requirements for the degree of Master of Environmental Science and Management for the Bren School of Environmental Science & Management

By Sara-Katherine Coxon C. Micah Eggleton Catherine Iantosca Jennifer Sajor Advisors: Naomi Tague & Jeff Dozier

Acknowledgements

We would like to thank the followings individuals for the time and knowledge they contributed to our project.

We would especially like to thank our project advisors, Drs. Naomi Tague, Jeff Dozier, and external advisor Lisa Leombruni (Bren) for the countless hours they spent providing advice and feedback on this project.

Ventura Water: Gina Dorrington (Wastewater Utility Manager), and Craig Jones (Management Analyst II)

City of Ventura: Ryan Kintz (Management Analyst)

Bren School: Alex DeGolia (PhD Candidate), Dr. Allison Horst (Visiting Faculty)

City of San Diego: Alma Rife (Senior Public Information Officer)

Orange County Water District: Eleanor Torres (Director of Public Affairs)

Northeastern University: Matthew Nisbet (Associate Professor of Communications, Policy & Urban Affairs)

California Lutheran University: Matt Fienup (Economist, Center for Economic Research & Forecasting) and Dr. Andrew Pattison (Department of Policy Studies, MPPA Program)

New Water ReSources: Linda MacPherson (Managing Member)

Table of Contents

ABSTRACT ................................................................................................................................ 1

DEFINITIONS ............................................................................................................................ 2

EXECUTIVE SUMMARY ............................................................................................................. 4

INTRODUCTION & PURPOSE .................................................................................................... 6

DATA COLLECTION METHODS .................................................................................................. 8 OVERVIEW ...................................................................................................................................... 8 STRUCTURED LITERATURE REVIEW ....................................................................................................... 8 SURVEYS ......................................................................................................................................... 9 Ventura Resident Survey .......................................................................................................... 9

Survey Distribution ......................................................................................................................................... 10 Survey Rationale ............................................................................................................................................. 10

Demonstration Facility Survey ............................................................................................... 13 Survey Distribution ......................................................................................................................................... 13

LIMITATIONS .................................................................................................................................. 14 Survey Limitations .................................................................................................................. 14 Data Limitations .................................................................................................................... 14

ANALYSIS & FINDINGS ........................................................................................................... 15 EMOTIONAL RESPONSE .................................................................................................................... 16 TRUST .......................................................................................................................................... 17 WATER QUALITY AND SAFETY ........................................................................................................... 21 INFORMATION AND EDUCATION ........................................................................................................ 24

WHO TO INFLUENCE .............................................................................................................. 28

OUTREACH STRATEGY RECOMMENDATIONS ......................................................................... 29 RECOMMENDATIONS METHODS ........................................................................................................ 29 TOP RECOMMENDATIONS ................................................................................................................ 29 IMMEDIATE IMPLEMENTATION .......................................................................................................... 29 LONG‐TERM IMPLEMENTATION ......................................................................................................... 31

EVALUATION ......................................................................................................................... 34 SAMPLE SIZES ................................................................................................................................ 34

CONCLUSION ......................................................................................................................... 36

REFERENCES .......................................................................................................................... 38

APPENDIX .............................................................................................................................. 42 APPENDIX 1: VENTURA RESIDENT SURVEY ........................................................................................... 42 APPENDIX 2: VENTURA RESIDENT SURVEY CONSENT FORM .................................................................... 48

APPENDIX 3: DEMONSTRATION FACILITY SURVEY .................................................................................. 49 APPENDIX 4: ADDITIONAL ANALYSES ‐ VENTURA RESIDENT SURVEY DATA ................................................. 52 APPENDIX 5: SURVEY RATIONAL TABLE ............................................................................................... 69 APPENDIX 6: EXAMPLE RECOMMENDATION SYNTHESIS .......................................................................... 72 APPENDIX 7: VENTURA DEMOGRAPHICS ............................................................................................. 73

Abstract 1

Abstract

Four years of intense drought have put increasing pressure on California’s dwindling water

supplies, prompting cities like Ventura to seriously consider where they will source their

drinking water from. Ventura’s primary sources, Lake Casitas and local groundwater supplies,

are not sufficient to meet the city’s long‐term demands. Given this, the city is evaluating the

feasibility of implementing Direct Potable Reuse (DPR) to augment the city’s drinking water

supplies in a sustainable and reliable way. DPR is the process of purifying treated wastewater

through several steps, including ultrafiltration and reverse osmosis, to drinking water standards

or higher before adding it directly back into the water system. While DPR comes with economic

and environmental benefits compared to alternative water supplies, it typically faces low public

acceptance rates due to skepticism and concerns around the source and treatment process. In

some cases, strong public opposition has been enough to shut down potable reuse projects

altogether.

In order for potable reuse water schemes to be successfully implemented, public concerns and

perceived risks must be addressed early in the planning process. This project lays out a

foundation for a comprehensive public outreach strategy, synthesizing best practices from the

available literature on outreach and communications of potable reuse projects, and applying

them to address specific concerns in Ventura. Recommendations are designed across four

themes, which were reoccurring in both literature and survey responses: communicating water

quality and safety, building trust in the water provider, responding to emotional reactions to

DPR (the “yuck factor”), and disseminating information about the reuse process. Although

applied to Ventura, the strategy could be adapted to other locations in California considering

potable reuse projects. By identifying underlying concerns and developing tailored

communications strategies to respond to them with, this project aims to increase awareness

and acceptance of DPR as a viable and secure drinking water source for Ventura.

Definitions 2

Definitions

● Advanced Water Treatment: Water treatment processes including microfiltration or

ultrafiltration, reverse osmosis, UV disinfection, and advanced oxidation that remove

nearly all non‐H2O biota and chemicals.

● Advanced Purified Water (APW): The end product of the potable reuse process, which

meets or exceeds drinking water quality standards.

● Direct Potable Reuse (DPR): The process by which treated wastewater effluent

undergoes advanced treatment processes usually including but not limited to micro

and/or ultrafiltration, reverse osmosis, and UV light disinfection with advanced

oxidation. The end result is water, often cleaner than most municipal sources, which is

then placed directly into a public drinking water system or into a water supply

immediately upstream of a water treatment plant.

● Indirect Potable Reuse (IPR): The process by which treated wastewater effluent

undergoes the same advanced treatment as Direct Potable Reuse (see definition above)

and is then pumped into a groundwater or above‐ground storage system where it is

retained and later treated for public drinking water supplies.

● Ultrafiltration: A membrane processes where raw water is filtered by passing through a

plastic or polymeric material which contains millions of small pores. Filtering occurs

because the membrane pores are large enough to allow water to pass through, yet

small enough to restrict the passage of undesirable materials such as particulate matter

and pathogenic organisms (Muilenberg, 2000).

● Primary Water Treatment: Treatment process that physically separates wastes from

water.

● Secondary water treatment: Process following primary treatment, which uses microbes

to break down, remove, and/or neutralize unwanted biological elements from water.

● Tertiary Water Treatment: Employs filters and/or disinfection to remove additional

unwanted biological material.

● Recycled Water (Purple Pipe): Water that has gone through primary, secondary, and

tertiary wastewater treatments, but not advanced processes such as microfiltration or

reverse osmosis. Often used to irrigate crops or landscaping, recycled water is pumped

through purple pipes so as to be recognized as non‐potable water. Term is

interchangeable with the term “reclaimed water”

● Reverse Osmosis: A treatment method that purifies drinking water by forcing untreated

water molecules through a semipermeable membrane or filter. The membrane blocks

contaminants, pharmaceuticals, dissolved chemicals, and other impurities, producing

nearly distilled‐quality water

Definitions 3

● Ultraviolet Light Disinfection with Advanced Oxidation: The use of ultraviolet light to

alter the DNA of cells of bacteria and microorganisms so that reproduction is impeded.

UV light treatment does not remove organisms from the water, but renders them

inactive (Water Research Center, 2014). Advanced oxidation uses highly reactive oxygen

to destroy any trace organic compounds that may have passed through the reverse

osmosis process.

● Wastewater: Water collected in a municipal sewer system, including water from homes

and businesses

Executive Summary 4

Executive Summary

The severity of California’s drought has increased pressure around the state to make scarce

water resources go further. Driven by dwindling water supplies, many cities are looking for

innovative methods to produce safe and reliable drinking water. Rather than turning to

desalination or importing water from across the state, some cities are beginning to focus on

recycling water already in use as an option for increasing drinking water supplies.

The City of Ventura is at the forefront of this transition, and is looking to implement an

advanced water reuse system within the next ten years. Known as direct potable reuse (DPR),

this process pumps treated wastewater through several purification steps to produce high

quality drinking water, before adding it directly back into the water system. Ventura has

partnered with the WateReuse Foundation and Carollo Engineers to construct a DPR

demonstration facility. Known as VenturaWaterPure, the facility aims to educate the public

about DPR and water treatment, while providing critical water quality data to demonstrate that

the process is reliable and resilient.

Signed in 2010, Senate Bill 918 is an important political driver of this transition. The bill

mandates researching the feasibility of implementing DPR, which has been identified as an

important part of California’s mandated water recycling goal. While the technology comes with

several economic and environmental benefits, public opposition to drinking purified

wastewater has historically been a major deterrent to successful implementation. Often

perceived as a risky, last‐resort water supply option that is less acceptable than desalination or

imported water, DPR projects have been derailed in the past by outspoken public opposition

groups. Addressing these concerns and perceived risks early in the planning process is a critical

component for successful implementation.

To address public concerns and perceived risks, this project recommends a series of outreach

strategies aimed at increasing public awareness and acceptance of DPR as a drinking water

source in Ventura. This project examines ongoing research in the sciences, psychology,

communications, and existing potable reuse case studies in the US and abroad to investigate

perceived risks and barriers to implementing DPR. We developed and distributed a resident

survey in order to identify specific concerns across four categories: water quality and safety

concerns, trust level in the water reuse authority, emotional reactions to drinking potable reuse

water (the “yuck factor”), and the availability and transparency of potable reuse information.

Backed by an extensive literature review, we developed a series of tailored recommendations

Executive Summary 5

that built upon effective framing and messaging techniques around water quality safety,

environmental co‐‐benefits, and economic benefits of potable reuse water.

Our hope is that, upon completion of the project, our outreach strategy will help our client

highlight the benefits of DPR as a sustainable, secure source of drinking water for Ventura ‐ a

strategy that could easily be applied to other areas of Southern California that are considering

similar water reuse technologies. Ultimately, our goal is to raise awareness and acceptance

rates of DPR as a drinking water source so that it can be successfully implemented in Ventura

within the next 10‐15 years.

Introduction & Purpose 6

Introduction & Purpose

The City of Ventura, California relies exclusively on local river, reservoir, and groundwater

supplies to meet its drinking water needs. These natural water sources are quickly dwindling as

a result of years of intense drought. The city’s primary water supply, Lake Casitas, is currently at

42% capacity (Casitas Municipal Water District, 2016), and Ventura does not currently have the

infrastructure to import water from the State Water Project. Given the pressure on local water

resources, Ventura is exploring alternative water technologies that would maximize reuse of

existing water supplies, providing a sustainable and secure water source for years to come.

Ventura Water is exploring Direct Potable Reuse (DPR) as an option for increasing the city’s

local water supply. DPR is the process of purifying treated wastewater through multiple

treatment steps to stringent water quality standards before pumping it directly back into the

drinking water system (Carollo Engineers). With DPR, wastewater is treated via pasteurization,

ultrafiltration, reverse osmosis, UV light disinfection with advanced oxidation, and/or other

advanced treatments. All of these processes disinfect and purify the water, removing even the

smallest of particles ‐ such as pharmaceuticals ‐ before adding it back to drinking water

supplies.

The city has determined that DPR is the most efficient and cost‐effective option given its

storage capabilities and budget constraints. DPR also comes with several advantages compared

to other water supply alternatives like desalination, imported water, or Indirect Potable Reuse

(IPR). It is less expensive than IPR, which requires additional energy to pump water into a

groundwater aquifer or surface reservoir. It is also less expensive and less energy intensive than

desalination (1.5 times the cost of DPR) (Martin, 2013), due to the lower concentration of salts

and constituents in the water.

However, low public acceptance rates are a major barrier to the implementation of DPR, due to

skepticism and concerns around the water source and treatment process. Communities often

perceive DPR as a risky, last‐resort water supply option that is less acceptable that desalination

or imported water. As a result, past water reuse projects in California have been derailed early

in the planning process, often by outspoken opposition groups. Ventura has identified

increasing public awareness and acceptance rates as a critical component to the successful

implementation of potable reuse. Ventura seeks to implement an outreach strategy for DPR to

increase public acceptance of potable reuse projects. If implemented proactively and early in

the planning process, the strategies outlined here will increase the chances of successfully

implementing DPR further down the road. Our primary objectives include:

Introduction & Purpose 7

1. Conduct a comprehensive literature review to distill common concerns around the

potable reuse process, and best practices for addressing them

2. Identify community‐specific concerns in Ventura around the use of direct potable reuse

as a drinking water source through the use of surveys

3. Develop a set of recommendations and outreach criteria to address key public concerns,

building upon best practices from literature and common concerns among Ventura

residents

This outreach strategy will provide Ventura Water with information and tools for increasing

acceptance of Direct Potable Reuse in Ventura. The strategy will analyze public opinion trends

around DPR as reported by Ventura residents, incorporate methods and best practices from an

extensive literature review on potable reuse implementation, and recommend tactics to

address common concerns such as modifying the information source or messaging format. By

implementing these strategies early on, Ventura can proactively respond to resident concerns

around DPR safety and reliability before they become major barriers. Taking steps to ensure

this information is available in a transparent and trustworthy manner will lay the foundation for

the successful implementation of DPR in the next 10‐15 years.

Data Collection Methods 8

Data Collection Methods

Overview

The field of DPR communications and outreach is already well‐explored, leaving us with an

extensive set of literature and case studies from which to distill best practices. We began by

conducting a literature review of over 36 academic papers and case studies on potable reuse

outreach to uncover common community concerns around water reuse projects, as well as best

practices on how these concerns were addressed in outreach campaigns. Key themes from the

literature were foundational to the three components of our outreach strategy.

In our next step, we surveyed over 250 Ventura residents on specific community concerns

around potable reuse, in order to decide on applicable best practices from our literature

synthesis (for full survey, see Appendix 1). Respondents answered questions regarding levels of

trust in community members, confidence in the reliability of the water treatment and water

quality, knowledge of water conservation efforts, and preference of potable reuse over

alternatives. Primary data was collected from both Ventura residents and Demonstration

Facility surveys, and was supplemented by Orange County water quality data and the literature

review to create an extensive and tailored outreach strategy for Ventura.

Structured Literature Review

The foundation of this outreach strategy is based in a thorough, structured literature review of

academic journals and communication strategy publications. Academic papers and case studies

were selected that focused on public perception, communications, and community outreach for

U.S.‐based water reuse and recycling projects (supplemented by a few studies on water reuse

outreach in Australia). Specific topics that were searched for included common

misconceptions, perceived risks, and psychological barriers that decreased public acceptance

rates; as well as key messages, delivery strategies, and frameworks that increased acceptance

rates of potable reuse.

Information ‐ both acceptance barriers and strategies for increasing acceptance ‐ was then

synthesized and categorized around four research themes: communicating water quality and

safety, building trust in the water reuse authority, responding to emotional reactions to potable

reuse (the “yuck factor”), and disseminating potable reuse information. We used keyword

searches around “safety”, “health”, “water quality”, “trust”, “psychology/emotion”,

“information”, and “education” to track and categorize these four main themes across the


literature. We tracked the number of times that specific public perception themes or

recommendations appeared in the literature in order to quantify the most prominent themes.

Surveys

Two surveys on potable reuse in Ventura were used to inform this outreach strategy:

1. A Ventura Resident Survey was distributed to Ventura community groups and the

general public between September 2015 and February 2016. The Resident Survey was

used to gauge the public’s opinion of potable reuse. Surveys were targeted to influential

community groups as well as the general public as a preliminary means of identifying

segments of the Ventura community that may be in support of or opposed to the

implementation of a potable reuse project in Ventura.

2. A Demonstration Facility Survey was distributed by Ventura Water to visitors during

tours of the VenturaWaterPure Demonstration Facility between June 2015 and February

2016. This survey had two purposes: determining whether education on potable reuse

led to increased levels of support, and gauging tour attendees’ views on potable reuse.

Ventura Resident Survey

The purpose of surveying Ventura residents was to provide quantifiable data on Ventura‐

specific concerns and attitudes on potable reuse. While some research has been done on

developing strategies of this type in California, it became clear that targeting our

recommendations to Ventura’s unique population would be important.

The survey consisted of 17 questions (some with multiple parts) in three different sections:

general water question to gauge background attitudes and water use of Ventura residents,

advanced purified water questions to gauge trust levels, emotional response, and concerns

around APW, and demographic questions (Appendix 1). Short descriptions and definitions of

technical water terms were included in order to ensure all respondents had the same baseline

knowledge before answering questions about potable reuse.

A total of 260 survey responses were collected in Ventura. The sample of community members

was collected as a convenience sample and was not intended to be a representative sample of

Ventura’s population but rather a snapshot of the views of segments of the Ventura

community.


Survey Distribution

Surveys were distributed between September 2015 and March 2016. The survey was

distributed in three ways: to members of Ventura community groups during group meetings,

and to the general public in communal areas, as well as online when necessary. This targeted

survey distribution was chosen as an efficient means of collecting data from specific segments

of the Ventura population. Our literature review identified influential community groups

important in the potable reuse development process (Dolnicar & Schäfer, 2009; Millan,

Tennyson, & Snyder, 2015). These groups are considered more likely to mobilize in favor of or

against public projects such as potable reuse. The identified groups included

community/volunteer groups, science/environmental groups, educators (teachers/PTA),

medical professionals, and local business owners. Future outreach should include all five

important community segments. The research team was able to reach three of the five

important community segments: community/volunteer groups, science/environmental groups,

and educators (teachers/PTA). The research team attended community group meetings, gave a

short introduction of the research project, and distributed the survey to participants. If time

permitted, we led a brief Question and Answer segment after the survey. Survey results were

used to compare and contrast opinions between segments.

Surveys were also distributed to the general public, who were assumed to be less engaged with

water issues in the community than community groups. It was recommended that including

more general public responses could help reduce bias found in the VenturaWaterPure

Demonstration Facility surveys, since respondents taking tours likely had greater levels of

existing interest and support in the project. General public survey distribution took place in

public areas, such as in downtown Ventura and outside grocery stores, where we assumed a

greater diversity of residents would be present. Surveys of the general public were compared to

the community group surveys to test whether there was a significant difference between the

views of the general public and the views of particular community groups.

Survey Rationale

Each survey question was designed to help reveal specific public perceptions of DPR,

corresponding with our four separate, but often overlapping research themes: emotional

response, trust in the water authority, safety/water quality concerns, and information and

education (Table 1; Appendix 1). Questions were designed to measure how levels of trust,

safety, and knowledge of water treatment and water reuse impacted respondent approval

levels for adding APW to Ventura’s drinking water supply (Question 5; Appendix 1).


Table 1. Truncated survey breakdown by construct.

Theoretical

Construct

Number of

Questions in

Survey

Example Survey Questions

Social Norm

Perceptions 4

3. How often do you conserve water in your own home? (e.g.

taking shorter showers, not watering your lawn, capturing the

cool water while you shower heats up for other household uses).

Emotional

Response 2

7d. Please rate the extent to which you agree/disagree with the

following statements about blending advanced purified water

with Ventura’s existing water supply: The source of the water

does not impact my comfort in drinking it.

Trust 20 4. How much would you say you trust Ventura Water to provide

safe drinking water?

Safety 4

7c. Please rate the extent to which you agree/disagree with the

following statements about blending advanced purified water

with Ventura’s existing water supply: I feel satisfied that there is

reliable monitoring throughout the treatment process.

Information 12

9g. How helpful would each of the following be for improving your

perceptions and your community's perceptions of drinking

advanced purified water in Ventura?: Economic benefits as

compared to other water supply options.

Demographic 7 13. Are there children (under 18 years) in your household?


Social Norm Perceptions

Water use and conservation practices were used to gauge baseline levels of water use

awareness in Ventura. Additionally, respondents were asked to rank community’s awareness

and conservation efforts. This not only provides a method to gauge the community’s water

conservation level, but was something that Ventura Water expressed interest in knowing.

Emotional Response

These perceptions can play a role in the negative emotional response residents tend to express

about recycled water. Targeted outreach to address some of these specific, culturally‐ingrained

feelings around drinking recycled water will be an important component to increasing

acceptance rates (Mankad and Tapsuwan, 2011; Rozin et al, 2004; Russell and Lux, 2009).

Trust

Respondent trust levels were examined in two different ways: trust in the water authorities to

provide safe drinking water, and trust in various information sources to provide messages

about DPR. Trust in water reuse authorities has been shown to greatly shape public perception

of other aspects of water reuse ‐ such as perception of water safety and system reliability

(Nancarrow, Leviston, & Tucker, 2009). For this reason, strategies to increase levels of trust in

Ventura Water ‐ with an emphasis on frequent distribution of transparent, accessible

information on the reuse process and water quality results ‐ are present in many of the

recommendations outlined in this report. Questions gauging trust levels in various

informational sources were adapted from various polling surveys (Probe Research Inc, 2014;

Millan, Tennyson, & Snyder, 2015).

Safety

Concerns around the safety of APW were shown to be some of the most prevalent regarding

perceptions of the DPR process (Dolnicar & Schäfer, 2009). Perceived safety of water sources

was tested alongside factors such as trust in local water providers, to explore any possible

relationships between the two. This was used to infer baseline safety perception levels of the

current water system in Ventura, to help to refine the type of messaging needed for the

outreach strategy (Hurlimann, 2007).

Information

The information construct explores both informational message content, and message

dissemination (format), around DPR. Questions identified both gaps in knowledge and

potentially useful information tools, which could then be used to develop effective messaging

channels and methods. These questions identified community opinions on persuasive


messaging and credible messengers of this information (Po et al., 2004; Marks, Martin, &

Zadoroznyj, 2008).

Demographic Correlations

A set of common DPR‐related demographic questions such as income, education, and ethnicity

were asked in order to explore possible correlations with levels of acceptance of advanced

purified water (Fink, 2003).

Demonstration Facility Survey

A Demonstration Facility survey was used to determine the role of education in potable reuse

acceptance. This survey was developed by Carollo Engineers, the consultant group who

developed the demonstration facility for Ventura. Information about tour dates and sign‐ups

were publicized through multiple local media channels.

Survey Distribution

VenturaWaterPure (potable reuse) tours began with a survey asking visitors about their

knowledge of Ventura’s water resources, drinking water preferences, and initial acceptance of

adding recycled water to their drinking water supply. After the survey, visitors listened to a 15‐

minute presentation on the DPR process. A demonstration facility tour followed, where

participants were provided with in‐depth information and an opportunity to explore equipment

for each of the four treatment processes used to purify recycled water. Tours ended with a

short video explaining the benefits of potable reuse, along with a Q&A session. Following the

tour, participants were surveyed again to determine whether perceptions of potable reuse had

changed.

The research team was not involved in the design of the Demonstration Facility survey. Major

analyses done on the data included before and after effects of the tour on support rankings and

synthesizing free response questions about the most persuasive aspects of the tour.


Limitations

Survey Limitations

The data collection process in Ventura presented several limitations. It quickly became evident

that obtaining a survey sample representative of Ventura (population 107,231 as of 2010)

(United States Census Bureau, 2015) would be impossible, due to time and budget constraints.

In addition, surveys were four pages long and no compensation was offered, which reduced

respondents’ willingness to participate.

Because of the limited number of surveys collected, it was difficult to obtain a survey sample

size that was demographically representative to Ventra. Latinos and Hispanics comprise a large

part of Ventura’s population, estimated to make up 31.8% as of the 2010 Census (United States

Census Bureau, 2015). Our own survey results included 17% Latino/Hispanic respondents. This

is a key limitation that should be addressed when sampling Ventura’s population more broadly.

Self‐report questionnaires, such as the one used for this project, are a popular methodology in

the behavioral sciences because of their utility and ease of distribution. However, as with all

self‐reporting surveys, there is always the risk of error related to respondent honesty,

introspective ability, interpretation of rating scales, and response bias (Hoskin, 2012). It is

important to consider these potential self‐report problems, as they may have an impact on the

validity of conclusions.

Data Limitations

A four‐month delay in the opening of the demonstration facility resulted in the delayed

availability of water quality data. Water quality data from the VenturaWaterPure pilot project

will play a fundamental role in communicating the safety and reliability of the water, and

should be incorporated into outreach efforts as soon as it is available.

Analysis & Findings 15

Analysis & Findings

The overall goal of the surveys was to gauge acceptance levels of DPR in Ventura as they relate

to the four theoretical constructs of the project, described in detail below. These four themes

were used to design the Ventura Resident Survey, and were used as an organizational

framework in which to explain survey findings. Concerns around water safety and the lack of

information about the process were prevalent results. Findings around trust levels and

emotional responses also contributed to understanding the underlying drivers behind DPR

skepticism. Results from both the Ventura Resident Survey and Demonstration Facility Survey

helped to confirm key findings from literature review as they apply to Ventura specifically.

The overarching question from the Ventura Resident Survey was to establish initial acceptance

levels of incorporating APW into city drinking water (Figure 1). Results indicated that 68% of

respondents moderately to strongly support the addition of APW, 22% felt neutral or unsure,

and 9% moderately to strongly opposed this addition (n = 249).

Figure 1. Support percentages of adding APW to Ventura’s drinking water supply, Ventura County. While

69% of respondents support the addition of APW (dark blue), 22% were unsure (gray) and 9% were

opposed (orange); n = 249 (see Appendix 1).

40%

29%

22%

6%3%

Q: How do you feel about adding advanced purified water to Ventura's drinking water supply if it was treated to the same

quality (or higher) as regular tap water?

Strongly Support

Moderately Support, buthave some concernsUnsure/No Fixed Opinion

Moderately Oppose

Strongly Oppose


While it’s encouraging to see such high levels of support, the one third of respondents who felt

neutrally or unsupportive of APW could pose a significant barrier to implementation. It is

important to get to know the concerns of these potentially affected interests, in order to best

address them moving forward. Our analysis focuses on concerns related to the four main

themes: emotional response, trust, safety and water quality, and information and education.

Emotional Response

A strong negative emotional response to recycled water, also known as the “yuck factor,” is

based on gut reactions rather than on rational thinking. As one Ventura Resident Survey

respondent put it, “Just the idea of drinking wastewater scares me.” Though commonly

attributed to the gap between scientific knowledge and public understanding, this visceral

reaction stems from culturally‐learned perceptions of clean and safe drinking water (Stenekes,

Colebatch, Waite & Ashbolt, 2006; Russell & Lux, 2009; Hartley, 2006; Mankad & Tapsuwan,

2011). Americans, in particular, have a strong preference for “natural” foods, which can be

applied to notions of consuming clean and safe drinking water (Rozin et al, 2004). This leads to

an instinctive aversion to drinking water that is not considered “natural” (i.e. processed

wastewater). Rozin et al. (2015) showed that increasing the storage time and distance traveled

between purification process completion and the drinking water system helped to restore the

idea of “naturalness” and increase willingness to drink advanced purified water. This may be

the reason why IPR (which uses the same treatment process, but introduces water into an

environmental buffer, such as a groundwater aquifer, for several months of storage before

drinking water use) could be seen as a more acceptable option by skeptics.

Naturalness with respect to the source of water affects its acceptability as drinking water. One

study determined that dissociating water from its source played a role in increasing support for

water reuse (Russell & Hampton, 2006). This is consistent with our survey findings, where

48.6% of respondents indicated that the source of advanced purified water impacts their

comfort in drinking it. One respondent stated, “APW needs to be of a higher quality due to the

enormous amounts of human waste metabolites that will be found.” This response

demonstrates that as a result of its source, advanced purified water is often perceived as dirtier

than other “natural” drinking water sources.


Figure 2. Safest water source according to respondents opposed to adding APW, Ventura County. Based

on respondents who were opposed to adding APW to Ventura’s drinking water supply (Question 5), 45%

of them considered bottled water (gray) the be the safest water source. Only 25% considered filtered

tap water (orange) to be the safest and 0% believed tap (blue) was the safest (n = 20).

Culturally learned ideas of safety also play a role in the yuck factor. Studies show that disgust‐

based aversion is attributed to perceived health concerns, which can be inaccurate (Nemeroff &

Rozin, 2000; Rozin & Nemeroff, 1990; Nemeroff & Rozin, 1994). For example, 45% of the survey

respondents that were opposed to adding APW to Ventura’s drinking water supply believed

that bottled water was the safest drinking water source (n = 20, Figure 2). This number

decreases to 22% (n = 144) for respondents who supported APW. Understanding how

perceptions of safe water sources ‐ both culturally learned and as a result of misinformation ‐

may affect one’s opinion of APW, and shed light on what a community deems as acceptable

drinking water.

Trust

Trust in the authorities that are managing DPR is a significant component in developing public

acceptance. Here, we define trust as the level of confidence communities have in the water

authority’s ability to maintain rigorous health and safety protocols in the production of APW

(Stanford, Walker, & Alexander, 2015). 64% of Ventura Resident Survey respondents indicated

0%

25%

45%

30%

Q: What water source do you consider the safest?(APW Opposed Segment)

Tap Water

Tap Water that is filtered

Bottled Water

All are equally safe


that they either highly or somewhat trust Ventura Water to provide safe drinking water to the

community (Figure 3).

A lack of trust in the responsible authority, shaped by a lack of transparency, inconsistent

messaging, and confusion around the authority’s motivation for pursuing a particular water

reuse scheme, has delayed and derailed water reuse project in the past (Nancarrow, Leviston,

& Tucker, 2009; WateReuse Association Webinar, 2016). It is therefore important that strategic

and transparent delivery of information from Ventura Water ‐ both on water quality and the

DPR process ‐ be included in any public outreach plan.

Increasing trust levels in the water authority also increases residents’ confidence in other

aspects of the water treatment scheme, such as water quality and system operations. A 2009

study on water reuse in Australia found that greater trust in the water authority directly

resulted in lower perceived health risk (perceived threat of the water on human health) and

system risk (perceived threat of something going wrong with the recycling process) (Nancarrow,

Leviston, & Tucker, 2009).

Figure 3. Trust levels in Ventura Water, Ventura County. 65% of respondents trust Ventura Water to

provide safe drinking water (blue), while only 10% distrusted (orange) and 25% were neutral (gray; n =

256).

33%

32%

25%

5%5%

Q: How much would you say you trust Ventura Water to provide safe drinking water?

Highly trust

Somewhat trust

Neutral

Somewhat distrust

Highly distrust


Among Ventura resident surveys, the most frequent concerns* related to trust in Ventura

Water included:

● Monitoring Concerns (“Need to make sure there is fail safe monitoring”; “Need to see

demonstrated ability to ensure safety”; “Would like to see daily water testing to make

sure it is safe”)

● Human Error Concerns (“Worried about margin of error/human error”; “Lapses in the

purification process”; “There are always chances for problems/slips, with this source of

water it would be particularly worrying”)

● Safeguarding Concerns (“Is there a failsafe system?”; “There can’t be any breakdown in

the APW treatment process or it will lose public support”; “Need to make sure there is

failsafe monitoring”

*Survey Question: Please list any specific concerns you have about drinking advanced purified

water that is blended with Ventura's existing water supply

The most frequent comments listed to gain support** for APW, also related to trust in Ventura

Water’s monitoring abilities, included:

● Testing & Reporting Transparency (“Testing to make sure it is safe”; “Transparency”;

“Reported levels of human waste metabolites; analysis procedures and identification of

what acceptable levels are”)

● Safety Assurance: (“Need to guarantee that people/residents won't get sick”; “Need a

better understanding of steps that would be taken to assure quality standards &

transparency of the process”; “Demonstrated ability to ensure safety of water”)

● “Proof” from other water reuse facilities: ( “Have it used for a year somewhere else to

test”; “Proof from other districts on taste, consistent monitoring, and most all knowing

other places did not get sick”)

**Survey Question: Please list any factors that would increase your support for adding advanced

purified water to Ventura's existing water supply.

Trust must also be taken into consideration when identifying the best source for distributing

information around APW and the DPR treatment process. The WateReuse Association

(Webinar, 2016) recommends the use of external water experts in disseminating information,

rather than local officials involved in the water scheme. Correspondingly, Ventura resident

survey results indicate that sources considered to be the most trustworthy for information

about advanced purified water were scientists, medical researchers, and independent lab

researchers (with 73%, 71%, and 70% of respondents selecting “Trust,” respectively).

Information sources associated with the highest levels of neutrality or distrust were local radio

stations, newspapers, City Council members, and the Mayor of Ventura (Figure 4).


Figure 4. Trust in different information sources about APW, Ventura County. The graph shows the most

trust source in descending order from top to bottom. Respondent most trusted third party source, such

as scientists (73%) and medical researchers (71%), to provide them with information about APW. Local

radio stations and newspapers were the least trusted.

0% 20% 40% 60% 80% 100%

The local radio stations (n=217)

The local newspapers (n=214)

Mayor of Ventura (n=214)

City Council members (n=217)

Taxpayer advocate organizations (n=216)

Local community leaders (n=216)

Local Business Owners (n=215)

The agricultural community (n=215)

Ventura Water Department (n=212)

Professors at local universities (n=218)

Nutritionists (n=215)

Environmental organizations (n=215)

Residents of a community that have already implementedpotable reuse (n=217)

Medical doctors (n=217)

Environmental Protection Agency (EPA) (n=215)

Department of Public Health (n=216)

Independent lab researchers (n=212)

Medical researchers (n=211)

Scientists (n=218)

The following is a list of people and organizations that may provide information about advanced purified water. Please tell us who you would generally trust or

distrust.

Trust

Neutral

Distrust


Water Quality and Safety

Water quality can be defined in several ways, depending on the audience. Some water users in

Ventura characterize quality in terms of taste, odor, and appearance. Conversely, other users

and water treatment managers characterize quality and safety by the regulation of levels of

constituents and pollutants in the water. As such, when communicating about quality and

safety of potable reuse, it is important describe “quality” in language relevant to each audience.

Some water users may be more concerned about how their water tastes or the mineral

content, while other are worried about pollutants and CEC’s.

Many people believe that APW contains more chemicals and microorganisms than other forms

of treated water (Dolnicar & Schäfer, 2009). The most frequently cited concerns involve the

presence of microorganisms (including bacteria, viruses, protozoa, and helminthes) (Dishman,

Sherrard, & Rebhun, 1989; Miller, 2006; Dolnicar & Schäfer, 2009; Crook, 2010; Chan, 2014),

trace organic compounds (such as pharmaceuticals or ‘‘endocrine disrupting chemicals’’)

(Dishman, Sherrard, & Rebhun, 1989; Miller, 2006; Dolnicar & Schäfer, 2009; Crook, 2010;

Chan, 2014), and hazardous chemicals that are byproducts of the treatment process (Dolnicar &

Schäfer, 2009). This is in addition to more common water contaminants including inorganic

pollutants such as nitrates, other nitrogenous compounds, and heavy metals (Dishman,

Sherrard, & Rebhun, 1989; Crook, 2010; Chan, 2014).

The two primary concerns identified in both the Ventura Resident Survey and Demonstration

Facility Survey were water quality and safety. For the Ventura Resident survey, approximately

53% of respondent comments brought up the safety of the potable reuse treatment process.

Although 48% of respondents were satisfied that there was reliable monitoring throughout the

treatment process, 32% felt unsure unsure (n = 232, Figure 7). Many respondents mentioned

that they worried about viruses, chemicals, and pharmaceuticals surviving the treatment

process, as well as the ability of the equipment to reliably detect these contaminants. Many

respondents also raised concerns about the possibility of human error or lack of safeguards

within the treatment process. Educating the public about the treatment process, safety

components, and monitoring built into the equipment is important for increasing support for

potable reuse (Crook, 2010; Chan, 2014). Making data readily available to the water users

about the levels of constituents in the water is also critical to increasing support (Yousef, 2011;

Schultz & Fielding, 2014; Crano & Prislin, 2006).

Based on our survey results, 64% of respondents agreed that they felt APW was safe enough to

drink (n = 245, Figure 5). However, 33% of respondents still preferred alternative water sources


like desalination (n = 245, Figure 6). Although the water treatment facility’s main concern is to

produce safe water, it is essential to communicate the quality of APW to the public.

Figure 5. Agreement with the statement that APW is clean enough to drink, Ventura County. 64% of

respondents agreed with the statement (blue), while both neutral and disagreement were 18% (gray

and orange, respectively; n = 245).

29%

35%

18%

10%

8%

Q: I feel that advanced purified water is clean enough to drink.

Strongly Agree

Somewhat Agree

Neutral

Somewhat Disagree

Strongly Disagree


Figure 6. Agreement with statement that alternative water supplies are preferable to APW, Ventura

County. 53% of respondents agreed with the statement (blue), while 19% were neutral (gray) and only

13% were in disagreement (orange; n = 245).

Figure 7. Agreement with the statement respondents are satisfied with the reliable monitoring

process of APW, Ventura County. 48% of respondents agreed with the statement (blue), while 32%

were neutral (gray) and 20% disagreed (orange; n = 232).

15%

18%

35%

19%

13%

Q: I feel other alternative water sources (e.g. desalination or imported water supplies) are preferable

Strongly AgreeSomewhat AgreeNeturalSomewhat DisagreeStrongly Disagree

19%

29%32%

13%

7%

Q: I feel satisfied that there is reliable monitoring throughout the treatment process

Strongly Agree

Somewhat Agree

Neutral

Somewhat Disagree

Strongly Disagree


Information and Education

Information about potable reuse projects, including the treatment process and associated risks,

plays a large role in public acceptance. Potable reuse is generally an unfamiliar topic for most

people, so information about the treatment process is the first basic piece of education that a

water utility should offer (Po et al., 2004; Hurlimann, 2007; Marks, Martin, & Zadoroznyj, 2008).

58% of the survey respondents collected in Ventura who left comments asked for more

information about the DPR treatment process, as well as its effectiveness and costs. Providing

this information will help residents to make an educated opinion about potable reuse in their

community.

The VenturaWaterPure Demonstration Facility tours offered an opportunity to test the effect of

education about the DPR process on support of DPR. Tour attendees were asked about their

support of potable reuse before the tour began, and asked the same question following the

tour, which included detailed information about the DPR treatment process and resulting water

quality. An analysis of Demonstration Facility Survey data indicated that education about the

DPR process significantly increased support for adding recycled water to Ventura's drinking

water supply (n = 276, pre‐tour rank mean = 3.79, post‐tour rank mean = 4.25), Z = 7.92, p <

0.001, r = 0.48; Figure 8). Tour attendees listed education about the treatment process,

including the multiple treatment steps and their effectiveness, as well as learning that potable

reuse has been successful and safe in other communities, among the factors that changed their

opinion about potable reuse.


Figure 8. Support about adding recycled water to Ventura’s drinking water supply, Ventura County.

Pre‐tour opinions (teal) were generally supportive. Post‐tour results (dark blue) showed a decrease in

opposed and neutral counts and an increase in support counts (n = 276).

Safety concerns are one of the major barriers water utilities must overcome prior to

implementing a potable reuse project (Miller, 2006; Yousef, 2011). Survey respondents in

Ventura raised concerns as to whether the DPR process could remove constituents such as

pharmaceuticals, herbicides, pesticides, and heavy metals. Respondents also expressed a desire

for transparency, consistent monitoring at the treatment facility, and guarantees that the

treatment process produces safe drinking water quality. Water utilities must emphasize that

safety is their biggest concern (Khan & Gerrard, 2006; Chan, 2014), as well as make sure to

address these common concerns early in the outreach process to begin overcoming possible

barriers to DPR project implementation. Water utilities must also be clear about the

parameters they are using when reporting on the safety of DPR; for example, explaining in

detail the criteria that are used to determine whether water is safe to drink (Russel & Hampton,

2005). One survey respondent in Ventura said they were “not sure how pure [the water] really

0

20

40

60

80

100

120

I stronglyoppose it

Moderatelyoppose

I am unsure /no fixed

opinion as yet

Moderatelysupport, buthave someconcerns

Stronglysupport it

Num

ber o

f Res

pond

ents

Q: How do you feel about adding recycled water to our drinking water supply?

Before tour

After tour


is,” while another was concerned with the margin of error allowed in the treatment process.

The water utility will need to clarify at what level various constituents are considered “safe” in

order to have full transparency in project implementation.

Data will be required to help convince the public of the safety of the DPR process. For example,

survey respondents in Ventura wanted to see water quality test results reported frequently to

the public. Although the water quality data itself can be an important persuader, the source of

information about DPR is also important in gaining public acceptance (Crano & Prislin, 2006;

Yousef, 2011). Endorsement from experts including engineers, scientists, doctors, and health

services can help to increase public acceptance of a potable reuse project (Dishman, Sherrard,

& Rebhun, 1989; Khan & Gerrard, 2006; Chan, 2014). Furthermore, examples of successful

projects in other areas can help to ease worries about potable reuse projects (Chan, 2014).

Regulatory approval is a key piece of information that can sway public opinion (Khan & Gerrard,

2006; Tchobanoglous, Leverenz, Nellor, & Crook, 2011; Chan, 2014). Respondents in Ventura

wanted to know that the project is following strict guidelines with oversight over the water

treatment process. Water utilities should emphasize that these standards are being met, that

water quality is being closely monitored, and that there is a failsafe in place to prevent against

possible contamination in the drinking water supply (Khan & Gerrard, 2006; Chan, 2014).

The Ventura Resident Survey asked respondents what would help improve their perceptions of

drinking advanced purified water. Respondents indicated that education about the treatment

process, a positive track record for potable reuse in other areas, and scientists reporting that

the treatment process was clean and safe would be most helpful in improving their

perceptions, the communities perceptions, or both (97%, 96%, and 94%, respectively; Figure 9).

These top strategies are in line with the factors that helped increase the perceptions of

Demonstration Facility tour survey respondents, and are strategies that Ventura Water should

focus on in their DPR outreach.


Figure 9. Desired information identified as helpful for improving perceptions of APW for themselves,

the community, or both, Ventura County. The graph shows the most helpful information for both the

respondent and their community in descending order from top to bottom. Top information included

education about the treatment process (97%) and showing a positive track record for potable reuse in

other areas (96%).

0% 20% 40% 60% 80% 100%

Support from community leaders/professionals (e.g.elected or health officials, etc.) (n=215)

The opportunity to taste the advanced purifiedwater (n=215)

State Water Regulators report that the treatmentprocess is clean and safe (n=215)

Economic benefits as compared to other watersupply options (n=214)

Environmental benefits as compared to other watersupply options (n=218)

Scientists report that the treatment process is cleanand safe (n=216)

A positive track record showing the success andsafety of potable reuse water in other areas (n=218)

Education about the treatment process (n=222)

How helpful would each of the following be for improving your perceptions and your community’s perceptions of drinking advanced purified water in Ventura?

Helpful to Both

Helpful to thecommunity

Helpful to me

Helpful toNeither

Who to Influence 28

Who to Influence

As with any proposed public project, the prospect of DPR in Ventura is met with one of three

types of response: support, uncertainty, and opposition. While a typical political campaign

seeks to identify which groups must be mobilized in order to gain voter support (Arceneaux &

Kolodny, 2009), this public outreach campaign aims to identify the concerns of opposed or

uncertain residents, in order to increase awareness and acceptance rates.

Opinions held by those in direct support and in opposition tend to be stronger and more

polarizing, making them less receptive to new information than those who are uncertain and

have yet to form a strong opinion (Holbrook & McClurg, 2005). This group represents Ventura

Water’s greatest opportunity for increasing acceptance. However, those who are uncertain are

also expected to encounter less outreach information as they are typically less engaged with

their communities, and with the planning process for public projects (Holbrook & McClurg,

2005). Reaching this group will be more difficult than reaching the partisan groups (Holbrook &

McClurg, 2005).

Over one third of Ventura respondents strongly disagree, somewhat disagree, or feel neutral

about Advanced Purified Water as a safe drinking water source, according to our survey

analysis. These respondents are the primary group that Ventura Water should be targeting

outreach toward. Understanding the characteristics of this group (how they are concentrated

geographically, demographically, and by other factors) should be the mission of future

surveying efforts, and will help ensure that outreach messages are delivered in a strategic and

targeted way possible (Schneider & Ingram, 1983).

Outreach Strategy Recommendations 29

Outreach Strategy Recommendations

Recommendations Methods

Outreach strategies identified through the literature review were compiled and synthesized

into a master list. Each recommendation was categorized according to the four main themes

identified in the literature: emotional response, trust, safety and water quality, and information

and education. For example, a literature recommendation to clearly describe the steps of the

DPR treatment process, emphasizing careful monitoring and oversight to ensure water quality,

would be categorized under both “water safety and quality” and “trust” themes. The

synthesized list of outreach strategies were then ranked by the number of times they were

cited in the literature, the number of different themes they address, and the amount of overlap

with concerns that were brought up by respondents in the Ventura Resident Survey and the

Demonstration Facility Survey.

Top Recommendations

The following are a condensed list of top recommendations for Ventura, which most accurately

address the concerns that were identified in our literature review and also appeared frequently

in the Ventura resident surveys. In addition, we outline below a more comprehensive list of

outreach strategies in two sections: immediate and easily‐implementable strategies aimed at

sharing basic information and establishing transparency, as well as more strategic, longer‐term

recommendations aimed at building trust and maintaining credibility.

1. Develop a clear explanation of the need for DPR.

2. Develop a clear explanation of the DPR treatment process.

3. Highlight the role of external experts in developing, implementing, and overseeing the

DPR process.

4. Promote examples of potable reuse success stories.

5. Provide opportunities for public participation early in the DPR planning process.

6. Evaluate effectiveness of proposed strategies.

7. Continue to survey to obtain a more representative sample.

Immediate Implementation

This list of recommendations are considered the “low‐hanging fruit” of an outreach strategy,

and includes several key, brief messages that should be shared early in the DPR planning


process. The messages focus on promoting safety, transparency, and demonstrating how DPR is

the necessary solution to a larger water supply problem. Implementing these steps can be

accomplished more quickly than some of the longer‐term, more involved recommendations.

Develop a clear explanation of the need for DPR, including broader water supply issues facing

the community and how DPR would help solve them. Furthermore, it must be clear that DPR is

a fundamental part of Ventura Water’s mission to provide sustainable, secure water supplies

(Institute for Participatory Management and Planning, 1994; Chan, 2014). [Information &

Education]

Example message: “Purified water enhances water supply reliability and helps protect us

from droughts by diversifying supply sources—keeping us from relying too much on any

one source of water that may run low in a drought. Currently, DPR is the best solution

for meeting this need.” (Millan, Tennyson, & Snyder, 2015)

Develop a clear explanation of the DPR treatment process, focusing on the multiple treatment

barriers and monitoring procedures. Explain the DPR process in terms that will resonate with a

non‐technical audience (MacPherson, 2010; Chan, 2014; Millan, Tennyson, & Snyder, 2015).

[Information & Education]

Example message: “The water is then treated through reverse osmosis, where it is

forced through membranes that remove salt and microorganisms, including viruses,

bacteria, and most chemicals of emerging concern.” (Millan, Tennyson, & Snyder, 2015)

Provide examples of successful potable reuse projects (both DPR and IPR) to demonstrate that

potable reuse has been successfully and safely implemented in the past (Khan & Gerrard, 2006;

Millan, Tennyson, & Snyder, 2015; WateReuse Association Webinar, 2016). [Safety,

Information, & Education]

Example message: “Purified water is currently used to supplement drinking water in

many communities in the United States and around the world. There have been no

problems from using purified water to augment drinking water supplies.” (Millan,

Tennyson, & Snyder, 2015)

Educate the public about the urban and natural water cycle to show that all water is recycled,

and that the treatment process is merely a replication of the nature's own water treatment

process (Millan, Tennyson, & Snyder, 2015; Khan & Gerrard, 2006). [Emotional Response]

Example message: “The amount of fresh water on the planet does not change, so

through nature all water has been used and reused since the beginning of time. Using

advanced technology to purify recycled water merely speeds up a natural process. In


fact, potable reuse provides a needed water supply that is of higher quality than what

occurs naturally.” (Millan, Tennyson, & Snyder, 2015)

Compare DPR water’s treatment process, its environmental impacts, and its economic

benefits to those of conventional and/or more trusted water sources (i.e. imported water,

desalinated water). (Khan & Gerrard, 2006; Dolnicar & Schäfer, 2008; Dolnicar, Hurlimann, &

Grün, 2011; Millan, Tennyson, & Snyder, 2015; WateReuse Webinar, 2016). [Safety,

information & Education]

Example message: "The DPR treatment process includes reverse osmosis, which is the

same filtration technology used in the desalination and bottled water processes.”

Example message: “The more recycled water we use for whatever purpose, the less we

have to take out of rivers, streams, and our scarce groundwater supplies. This is good

for rivers and streams and the fish, plants, and wildlife that rely upon them. We all

recycle as often as we can— glass, plastic, paper, and even yard waste—which is the

right thing to do. For the same reason, we should recycle and reuse as much of our

limited water supplies as we possibly can—water is too valuable to be used just once.”

(Millan, Tennyson, & Snyder, 2015)

Leverage words like "pure" and "advanced purified", which are more reassuring to the public

than other technical reuse terms such as "reuse", "recycled", and "wastewater" (MacPherson,

2010; WateReuse Association Webinar, 2016; Millan, Tennyson, & Snyder, 2015). [Emotional

Response]

Promote safety as the water treatment organization's highest priority in order to bolster and

grow their reputation (Khan & Gerrard, 2006; Chan, 2014; Millan, Tennyson, & Snyder, 2015).

[Safety, Information & Education]

Emphasize that the DPR process was developed with guidance from regulators, scientists, and

health services, and that the health and safety of advanced purified water will be overseen by

health services and regulatory authorities (Khan & Gerrard, 2006; Crook, 2010; Yousef, 2011;

Millan, Tennyson, & Snyder, 2015). [Information & Education]

Long‐Term Implementation

This is a set of recommendations which should be implemented throughout the duration of the

planning and implementation process. They focus less on immediate messages, and more on

building trust, transparency, and a space for public interaction in the long term.


Emphasize the quality tests that must be conducted and water standards that must be met

prior to distributing water to customers. A key message should be that water is rigorously and

reliably tested for drinking safety before distribution (Chan, 2014; WateReuse Association

Webinar, 2016). [Safety, Information, & Education]

Example message: “Purified water is tested, in real‐time, with online sensors and will be

strictly monitored by the Department of Health.” (Millan, Tennyson, & Snyder, 2015)

Continually compare the treatment process and water quality of DPR to trusted water

sources. Bottled water is viewed by many community members as the safest source of drinking

water, so it is useful to compare the quality of bottled water to the quality of water produced

through the DPR process (Dolnicar & Schäfer, 2008; WateReuse Association Webinar, 2016). [Emotional Response]

Example message: “The purification process produces water that is more pure than

most bottled waters.” (Millan, Tennyson, & Snyder, 2015)

Provide transparent water quality and monitoring reports, which include potential impacts of pharmaceuticals and fail‐safe guards used in the treatment process (Yousef, 2011; WateReuse Association Webinar, 2016). [Trust, Safety] Clearly define water "safety" criteria, such as commonly tested contaminant levels (Russell &

Hampton, 2005). [Safety]

Emphasize the quality and reliability of advanced purified water, while minimizing the focus

on the source of the water (Chan, 2014). [Emotional Response]

Provide a space for public participation in the planning of potable reuse projects. Community

members must view the process as fair, so water utilities should provide detailed information

about the safety procedures and possible risks associated with potable reuse projects and

incorporate community feedback into their finalized plans (Stenekes et al., 2006; Ross, Fielding,

& Louis, 2014; Hurlimann, 2008; Hartley, 2006). [Trust]

Conduct potable reuse facility tours. Tours can be used to demonstrate the treatment process

and safeguards that are in place. They also allow community members to see the quality of

advanced purified water with their own eyes and taste the water for themselves (Dolnicar,

Hurlimann, & Grün, 2011; Dolnicar & Grun, 2011; Millan, Tennyson, & Snyder, 2015; Goetz,

2015). [Safety, Information & Education]

Understand oppositional groups: who/where they are, what their interests are, what

acceptance barriers are (Institute for Participatory Management and Planning, 1994).


Continue to survey residents to obtain a more representative sample of the Ventura

community. Continued sampling will help Ventura to develop a better understanding of

resident needs and concerns, improving statistics on community acceptance levels.

Evaluate the effectiveness of proposed strategies. It is important to continually re‐evaluate

communications strategies to refine which messages are having the greatest impact in the

Ventura community.

Evaluation 34

Evaluation

It will be important for Ventura to monitor the success of their outreach strategies, and

although there is limited research into the quantitative methods for this evaluation, we

recommend the following next steps:

1. Continue to distribute the Ventura Resident Survey, and reevaluate the percent of

residents that are supportive of DPR annually to track any changes in this trend (Chan,

2014). See Sample Sizes section below for more detail.

2. Test the effectiveness of chosen education and outreach materials with surveys before

and after outreach is conducted.

3. Adjust outreach materials over time to ensure relevance to the community.

4. Engage key community groups to hold in‐depth and open discussions about DPR to

highlight new and emerging concerns around potable reuse. This can help Ventura

better tailor its outreach material, strategy, and message (Rowe & Frewer, 2000).

Sample Sizes

Continuous surveying throughout the lifespan of the project will be critical for accurately

gauging public acceptance of DPR. A representative sample is needed and will be more

reflective of demographic distributions in Ventura. In order to determine the sample size

needed, Ventura Water will need to decide the desired accuracy (confidence level) and

precision (margin of error) values for survey results. Results from Table 2 reflect ideal sample

sizes. Moderate values to pick are a 3% margin of error with a 95% confidence level.

Furthermore, minimum sample sizes to obtain an appropriate power of 80% for statistical tests

used in this report have been listed in Table 3. An 80% power reflects the minimum sample size

needed to greatly reduce the chance of incorrectly finding the results of a statistical analysis to

be insignificant.

Evaluation 35

Table 2. Sample sizes needed for representative sample based on confidence level and margin of

error. Results based on a Ventura population size of 107,231 (US Census Bureau, 2015).

Confidence Level: 95% Confidence Level: 99%

Margin of Error 1% 3% 5% 1% 3% 5%

Sample Size 8,815 1,057 383 14,366 1,812 660

Table 3. Minimum sample size needed for a power of 80% for various statistical analyses.

Test Min. Sample Size

Chi‐Squared 151

Wilcoxon Signed‐Rank 38

Conclusion 36

Conclusion

The goal of this project was to develop a tailored DPR outreach strategy to increase

public awareness and acceptance rates in Ventura, enough to enable successful project

implementation within 5‐10 years. Though technical and regulatory hurdles have the potential

to delay implementation, public opposition remains the biggest factor in the derailment of DPR

projects. An effective outreach strategy aimed at increasing public acceptance of DPR is critical

to mitigate public opposition and set the stage for successful implementation.

A structured literature review of studies focused on public perceptions,

communications, and outreach of recycled water projects was used to design a Ventura‐specific

public opinion survey (Ventura Resident Survey, Appendix 1). In addition, the literature review

was used in conjunction with survey results to distill best practices and outreach strategies that

most accurately fit the needs of Ventura. The theoretical constructs used to categorize public

perceptions and concerns were emotional response, trust, water safety and quality, and

information/education dissemination. The consultant‐designed Demonstration Facility Survey

was used to supplement the findings of the Ventura Resident Survey, and study the role of a

demonstration facility tour in shaping perceptions of DPR.

Key survey findings:

22% of respondents were unsure about whether they would support adding APW to

Ventura’s drinking water supply while 9% of respondents were somewhat or moderately

opposed to the idea.

64% of respondents stated they somewhat or highly trust Ventura Water to provide safe

drinking water.

Top concerns around APW include the idea of drinking recycled water, trust in Ventura

Water to provide transparent information about water quality, the potential presence of

pharmaceuticals and other contaminants in the water, and the reliability of monitoring

process.

The majority of respondents didn’t understand the treatment process, and want more

information on it before developing an opinion.

64% of survey respondents feel that APW is clean enough to drink.

Top three trusted sources of information on APW include scientists (73%), medical

researchers (71%), and independent lab researchers (70%).

Conclusion 37

Education about the treatment process and potable reuse in general (Demonstration

Facility tours) significantly increased support of adding recycled water to Ventura’s

drinking water supply.

Key outreach recommendations:

1. Develop a clear explanation of the need for DPR.

2. Develop a clear explanation of the DPR treatment process.

3. Highlight the role of external experts in developing, implementing, and overseeing the

DPR process.

4. Promote examples of potable reuse success stories.

5. Provide opportunities for public participation early in the DPR planning process.

6. Evaluate effectiveness of proposed strategies.

7. Continue to survey to obtain a more representative sample.

The outreach recommendations in this report target some of the major concerns and perceived

risks around DPR use. If implemented in advance, with special attention paid to identifying

characteristics of oppositional groups, these strategies will increase awareness and acceptance

rates in the city to allow for smoother implementation of DPR.

References 38

References

Arceneaux, K., & Kolodny, R.. (2009). Educating the Least Informed: Group Endorsements in a Grassroots Campaign. American Journal of Political Science, 53(4), 755–770. Retrieved from http://www.jstor.org/stable/20647949

B. E. Nancarrow, Z. Leviston and D. I. Tucker. (2009). Measuring the predictors of communities’

behavioural decisions for potable reuse of wastewater. Water Science & Technology.

Carollo Engineers. (n.d.). Carollo Engineers Supports California Direct Potable Reuse Initiative.

Retrieved from http://www.carollo.com/sites/default/files/news/DrinkinWaterSupport.pdf

Casitas Municipal Water District. (2016). Lake Level. Casitas Municipal Water District. Retrieved

from http://www.casitaswater.org/lower.php?url=lake‐level

Chan, A. (2014, December 12). The Future of Direct Potable Reuse in California Overcoming

Public Acceptance Barriers. University of San Francisco.

Claritas Tech Support (2009). City of Ventura Demographic Snapshot Report. (2016, 11 March).

Retreived from http://www.cityofventura.net/.

Crano, W., & Prislin, R. (2006). Attitudes and Persuasion. Annual Review of Psychology, 57, 345–

374. http://doi.org/10.1146/annurev.psych.57.102904.190034

Crook, J. (2010). Regulatory Aspects of Direct Potable Reuse in California. National Water

Research Institute.

Dishman, C. M., Sherrard, J. H., Member, ASCE, & Rehun, M. (1989). Gaining Support for Direct

Potable Water Reuse. Journal of Professional Issues in Engineering, 115(2), 154–161.

http://doi.org/10.1061/(ASCE)1052‐3928(1989)115:2(154)

Dolnicar, S., & Schäfer, A. I. (2009). Desalinated versus recycled water: Public perceptions and

profiles of the accepters. Journal of Environmental Management, 90(2), 888–900.

http://doi.org/10.1016/j.jenvman.2008.02.003

Fink, A. (2003). The Survey Handbook. SAGE. Goetz, M.K. (2015). Risky Business: Factoring in Public Perceptions. Journal AWWA, 107:3:77.

Product No. JAW_0081663.

Groundwater Replenishment System 2014 Annual Report. (2015, May 17). Orange County

Water District. Retrieved from

http://www.ocwd.com/media/3488/2014_gwrs_annual_report_final.pdf

Hartley, T. W. (2006). Public perception and participation in water reuse. Desalination, 187(1–

3), 115–126. http://doi.org/10.1016/j.desal.2005.04.072

Holbrook, T. M., & McClurg, S. D.. (2005). The Mobilization of Core Supporters: Campaigns, Turnout, and Electoral Composition in United States Presidential Elections. American Journal of Political Science, 49(4), 689–703. http://doi.org/10.2307/3647691

Hoskin, Rob (2012). The dangers of self‐report ‐ Science Brainwaves. Retrieved from

http://www.sciencebrainwaves.com/the‐dangers‐of‐self‐report/

References 39

Hurlimann, A. C. (2007). Is recycled water use risky? An Urban Australian community’s

perspective. The Environmentalist, 27(1), 83–94. http://doi.org/10.1007/s10669‐007‐9019‐

6

Institute for Participatory Management and Planning. (1994). Citizen Participation Handbook

(Eighth Edition). Monterey, California: IPMP.

Khan, S. J., & Gerrard, L. E. (2006). Stakeholder communications for successful water reuse

operations. Desalination, 187(1–3), 191–202. http://doi.org/10.1016/j.desal.2005.04.079

Mankad, A., & Tapsuwan, S. (2011). Review of socio‐economic drivers of community

acceptance and adoption of decentralised water systems. Journal of Environmental

Management, 92(3), 380–391. http://doi.org/10.1016/j.jenvman.2010.10.037

Marks, J., Martin, B., & Zadoroznyj, M. (2008). How Australians order acceptance of recycled

water National baseline data. Journal of Sociology, 44(1), 83–99.

http://doi.org/10.1177/1440783307085844

Martin, L. (2013, November 4). Direct Potable Reuse Vs. Indirect: Weighing The Pros And Cons.

Water Online. Retrieved from http://www.wateronline.com/doc/direct‐potable‐reuse‐vs‐

indirect‐weighing‐the‐pros‐and‐cons‐0001

Millan, M., Tennyson, P., & Snyder, S. (2015). Model Communication Plans for Increasing

Awareness and Fostering Acceptance of Direct Potable Reuse (p. 260). WateReuse Research

Foundation.

Muilenberg, T. (2000, December 28). Microfiltration: How Does it Compare?

[Information/Articles]. Retrieved from

http://www.wwdmag.com/desalination/microfiltration‐how‐does‐it‐compare

Nemeroff, C., & Rozin, P. (1994). The contagion concept in adult thinking in the United States:

transmission of germs and interpersonal influence. Ethos, 22, 158–186.

Po, M., Nancarrow, B. E., Leviston, Z., Porter, N. B., Syme, G. J., & Kaercher, J. (2005, May).

Predicting Community Behaviour in Relation to Wastewater Reuse. Natural Heritage Trust.

Retrieved from

http://www.clw.csiro.au/publications/consultancy/2005/WfHC_Predicting_Reuse_Behavio

ur.pdf

Probe Research Inc. (2014). 2014 Water Issues Public Opinion Poll. San Diego County Water

Authority. Retrieved from http://www.sdcwa.org/sites/default/files/files/news‐

center/2014‐public‐opinon‐poll.pdf

Rowe, G., & Frewer, L. J. (2000). Public Participation Methods: A Framework for Evaluation. Science, Technology, & Human Values, 25(1), 3–29.

Rozin, P., Haddad, B., Nemeroff, C., & Slovic, P. (2015). Psychological aspects of the rejection of

recycled water: Contamination, purification and disgust. Judgment and Decision Making,

10(1), 50–63.

References 40

Rozin, P., & Nemeroff, C. J. (1990). The laws of sympathetic magic: a psychological analysis of

similarity and contagion. Cultural Psychology: Essays on Comparative Human Development,

205–232.

Rozin, P., Spranca, M., Krieger, Z., Neuhaus, R., Surillo, D., Swerdlin, A., & Wood, K. (2004).

Natural preference: instrumental and ideational/moral motivations, and the contrast

between foods and medicines. Appetite, 43, 147–154.

Russell, S., & Hampton, G. (2006). Challenges in understanding public responses and providing

effective public consultation on water reuse. Desalination, 187(1–3), 215–227.

http://doi.org/10.1016/j.desal.2005.04.081

Russell, S., & Lux, C. (2009). Getting over yuck: moving from psychological to cultural and

sociotechnical analyses of responses to water recycling. Water Policy, 11(1), 21–35.

http://doi.org/10.2166/wp.2009.007

Schneider, A., & Ingram, H.. (1993). Social Construction of Target Populations: Implications for

Politics and Policy. The American Political Science Review, 87(2), 334–347.

http://doi.org/10.2307/2939044

Schultz, T., & Fielding, K. (2014). The common in‐group identity model enhances

communication about recycled water. Journal of Environmental Psychology, 40, 296–305.

http://doi.org/10.1016/j.jenvp.2014.07.006

Stanford, B., Walker, T., & Alexander, K. (2015, April 29). Engineering Trust in Direct Potable

Reuse. Hazen and Sawyer. Retrieved from

http://www.hazenandsawyer.com/publications/engineering‐trust‐in‐direct‐potable‐reuse/

Stenekes, N., Colebatch, H. K., Waite, T. D., & Ashbolt, N. J. (2006). Risk and Governance in

Water Recycling: Public Acceptance Revisited. Science, Technology, & Human Values, 31(2),

107–134.

Tchobanoglous, G., Leverenz, H., Nellor, M., & Crook, J. (2011). Direct Potable Reuse: A path

forward (p. 103). WateReuse Foundation.

United States Census Bureau (2015). QuickFacts: San Buenaventura (Ventura) city,

California, 2010. http://www.census.gov/quickfacts/table/PST045215/0665042.

UV Disinfection. (n.d.). Retrieved March 15, 2016, from http://www.water‐

research.net/index.php/water‐treatment/water‐disinfection/uv‐disinfection

Wade Miller, G. (2006). Integrated concepts in water reuse: managing global water needs.

Desalination, 187(1–3), 65–75. http://doi.org/10.1016/j.desal.2005.04.068

WateReuse Association. (n.d.). Managing Water Supply Replenishment. Water Reuse

Association. Retrieved from https://www.watereuse.org/water‐

replenish/pdf/Executive%20Summary.pdf

WateReuse Association. Potable Reuse Communications: A Specialty Workshop for Agencies and

Public Information Professionals. Attended January 28, 2016.

References 41

Yousef, A. (2011). An Analysis of the Communication Process between the Orange County Water

District and the Public Regarding the Water Supply. University of California, Irvine.

Retrieved from

http://ppd.soceco.uci.edu/sites/ppd.soceco.uci.edu/files/users/jsumcad/2011%20Yousef%

20PR%20(Communicating%20H20%20science)_0.pdf

Appendix 42

Appendix

Appendix 1: Ventura Resident Survey

Appendix 43

Appendix 44

Appendix 45

Appendix 46

Appendix 47

Appendix 48

Appendix 2: Ventura Resident Survey Consent Form Bren School Research Consent Form, Ventura Potable Reuse Survey

PURPOSE:

You are being asked to participate in a research study. The purpose of the study is to determine public barriers, perceived risks,

and best practices that may be used to identify criteria for an effective strategy for promoting advanced purified water as a

water source in Ventura.

PROCEDURES:

The meeting will involve a brief introduction to our study, a 10‐minute anonymous survey, and a <15‐minute discussion (if time

permits) about the topic of potable reuse in Ventura. You must be at least 18 years of age and a resident of the city of Ventura

to participate.

RISKS:

There are no risks, discomforts and/or inconveniences that may result to you for participation in this study.

BENEFITS:

There may be no direct benefit to you anticipated from your participation in this study, however, your responses to this survey

may help the City of Ventura to pursue an additional water source that may be more reliable and/or drought resistant for the

residents and/or water customers in the City of Ventura.

CONFIDENTIALITY:

This survey will be completely anonymous. The data we collect will not be linked to your identity in any way.

RIGHT TO REFUSE OR WITHDRAW:

You may refuse to participate and still receive any benefits you would receive if you were not in the study. You may change

your mind about being in the study and quit after the study has started.

By completing this survey, you are consenting to have your anonymous responses included in our study analysis.

QUESTIONS:

If you have any questions about this research project or if you think you may have been injured as a result of your participation,

please contact:

[email protected] or visit VenturaPotableReuse.weebly.com

If you have any questions regarding your rights and participation as a research subject, please contact the UCSB Human

Subjects Committee at (805) 893‐3807 or [email protected].

Appendix 49

Appendix 3: Demonstration Facility Survey

Appendix 50

Appendix 51

Appendix 52

Appendix 4: Additional Analyses ‐ Ventura Resident

Survey Data

Segmented Analyses: evaluating the differences between groups within Ventura community

Q9 Segmented analyses

All data

0% 20% 40% 60% 80% 100%










Helpful to Both


Helpful to me

Helpful toNeither

Appendix 53

General

Community

0% 20% 40% 60% 80% 100%










Respondents from the General Public community segment

Helpful to Both

Helpful to thecommunityHelpful to me

Helpful to Neither

0% 20% 40% 60% 80% 100%










Respondents from the Community/Volunteer community segment

Helpful to Both

Helpful to thecommunityHelpful to me

Helpful to Neither

Appendix 54

Education

Environmental/science

0% 20% 40% 60% 80% 100%






Economic benefits as compared to other watersupply options (16)




Respondents from the Educator community segment

Helpful to Both


Helpful to me

Helpful to Neither

0% 20% 40% 60% 80% 100%










Respondents from the Science/Environmental community segment

Helpful to Both


Helpful to me

Helpful to Neither

Appendix 55

______________________________________________________________________________

Question 9: How helpful would each of the following be for improving your perceptions and your

community’s perceptions of drinking advanced purified water in Ventura?

Segmented by support for adding advanced purified water to the water supply versus opposition.

Question Proportion selecting helpful to

me, community, or both

Significant difference? (p ≤ 0.05)

How helpful would each of the

following be for improving your

perceptions and your community’s

perceptions of drinking advanced

purified water in Ventura?

Support adding APW

Oppose adding APW

9a: Education about the treatment process

100% 84% Yes

(p < 0.001)

9b: Scientists report that the treatment process is clean and safe

96% 89% No

(p = 0.49)

9c: State Water Regulators report that the treatment process is clean and safe

88% 80% No

(p = 0.48)

9d: Support from community leaders/professionals (e.g. elected or health officials, etc.)

86% 65% Yes

(p = 0.04)

9e: The opportunity to taste the advanced purified water

85% 63% Yes

(p = 0.04)

9f: A positive track record showing the success and safety of potable reuse water in other areas

99% 75% Yes

(p < 0.001)

9g: Economic benefits as compared to other water supply options

97% 74% Yes

(p < 0.001)

9h: Environmental benefits as compared to other water supply options

97% 70% Yes

(p < 0.001)

Appendix 56

Support

Neutral

0% 20% 40% 60% 80% 100%










Respondents who support adding advanced purified water to Ventura's drinking water supply

Helpful to Both


Helpful to me

Helpful to Neither

0% 20% 40% 60% 80% 100%










Respondents unsure about adding advanced purified water to Ventura's drinking water supply

Helpful to Both


Helpful to me

Helpful to Neither

Appendix 57

Opposed

0% 20% 40% 60% 80% 100%



Environmental benefits as compared to other watersupply option (n=20)







Respondents opposed to adding Advanced Purified Water to Ventura's drinking water supply

Helpful to Both


Helpful to me

Helpful to Neither

Appendix 58

Q10 Segmented analyses

All data

0% 20% 40% 60% 80% 100%













Residents of a community that have already implementedpotable reuse (n=80)






Scientists (n=80)

The following is a list of people and organizations that may provide information about advanced purified water. Please tell us who you would generally trust or distrust.

Trust Neutral Distrust

Appendix 59

General

0% 20% 40% 60% 80% 100%













Residents of a community that have already implemented potablereuse (n=80)






Scientists (n=80)


Respondents from the General Public community segment


Appendix 60

Community

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

















Scientists (n=69)




Respondents from the Community/Volunteer community segment


Appendix 61

Education

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%



















Scientists (n=16)


Respondents from the Educator community segment


Appendix 62

Environment/Science

___________________________________________________________________________________

Question 10: The following is a list of people and organizations that may provide information about

advanced purified water. Please tell us whether you would generally trust or distrust each on this issue.

Segmented by support for adding advanced purified water to the water supply versus opposition.

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%



















Scientists (n=53)


Respondents from the Science/Environmental community segment


Appendix 63

Question Proportion selecting trust or

neutral

Significant difference? (p ≤ 0.05)

The following is a list of people and

organizations that may provide information

about advanced purified water. Please tell us

whether you would generally trust or distrust

each on this issue.

Support adding APW

Oppose adding APW

10a: Department of Public Health 92% 85% No (p = 0.48)

10b: Local Business Owners 78% 79% No (p = 1)

10c: Nutritionists 93% 84% No (p = 0.37)

10d: Environmental Protection Agency (EPA)

88% 74% No (p = 0.20)

10e: Residents of a community that have already implemented potable reuse

95% 95% No (p = 1)

10f: Environmental organizations 86% 80% No(p = 0.75)

10g: Independent lab researchers 95% 95% No (p = 1)

10h: Ventura Water Department 86% 74% No (p = 0.28)

10i: Medical researchers 95% 95% No (p = 1)

10j: The local newspapers 70% 70% No (p = 1)

10k: Mayor of Ventura 77% 70% No (p = 0.66)

10l: Local community leaders 79% 70% No (p = 0.53)

10m: City Council members 74% 70% No (p = 0.94)

10n: Scientists 97% 100% No (p = 1)

10o: Taxpayer advocate organizations 63% 70% No (p = 0.72)

10p: Medical doctors 93% 90% No (p = 0.95)

10q: The agricultural community 78% 65% No (p = 0.29)

10r: The local radio stations 73% 75% No (p = 0.21)

10s: Professors at local universities 92% 75% No (p = 0.052)

Appendix 64

Support

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%





Taxpayer advocate organizations














Scientists (n=146)


Respondents who support adding Advanced Purified Water to Ventura's drinking water sup


Appendix 65

Neutral

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%


















Scientists (n=46)



Respondents unsure about adding advanced purified water to Ventura's drinking water su


Appendix 66

Opposed

Ordered Logistic Regression: determining whether survey responses help to predict respondent’s

support for adding APW to Ventura’s drinking water supply

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%


















Scientists (n=20)



Respondents who oppose adding advanced purified water to Ventura's drinking water supp


Appendix 67

An ordered logistic regression on the Ventura Resident Survey results revealed that the frequency that

respondents consider the quality of their drinking water, the frequency that respondents take action to

conserve water, and trust in the water utility did not significantly predict a respondent's level of support

for potable reuse (Table 1).

Table 1.

Term Coefficient Standard Error p‐value Odds Ratio 95% Confidence Interval

Safety ‐0.016 0.094 0.87 0.98 [0.82, 1.18]

Conservation ‐0.035 0.160 0.83 0.97 [0.70, 1.32]

Trust 0.197 0.124 0.11 1.22 [0.96, 1.55]

An ordered logistic regression on the Ventura Resident Survey results revealed that Education level

significantly predicted a respondent’s level of support for potable reuse (Table 2). The respondent’s age,

gender, and status as a parent of children under 18 did not significantly predict the respondent’s

support for potable reuse (Table 2).

As education level increases, the odds of having a higher support level for potable reuse increase. As the

level of education increases, the odds of being somewhat supportive or extremely supportive; as

opposed to somewhat opposed, extremely opposed, or neutral; increases by 27% (with a confidence

interval between 5‐53% increase) (Table 2).

Table 2.

Term Coefficient Standard Error p‐value Odds Ratio 95% Confidence Interval

Age ‐0.249 0.141 0.077 0.78 [0.59, 1.03]

Gender ‐0.470 0.276 0.088 0.66 [0.36, 1.07]

Kids ‐0.299 0.322 0.354 0.74 [0.39, 1.40]

Education 0.237 0.097 0.014 1.27 [1.05, 1.53]

Chi‐square results? Q5xQ4, Q5xQ1, Q4xQ1

Appendix 68

Figure 9. Shows the perceived community acceptance for potable reuse as a water source alternative by

survey takers. This is question six in the Ventura Resident Survey.

Appendix 69

Appendix 5: Survey Rational Table

Theoretical Construct Related Survey Questions

Social Norm Perceptions

3. How often do you conserve water in your own home? (e.g. taking shorter showers, not watering your lawn, capturing the cool water while you shower heats up for other household uses).

6. How do you think your local community would feel about adding advanced purified water to Ventura’s drinking water supply if it was treated to the same quality (or higher) as regular tap water?

7d. Please rate the extent to which you agree/disagree with the following statements about blending advanced purified water with Ventura’s existing water supply: The source of the water does not impact my comfort in drinking it.

9. How helpful would each of the following be for improving your perceptions and your community’s perceptions of drinking advanced purified water in Ventura?

Emotional Response 7d. Please rate the extent to which you agree/disagree with the following statements about blending advanced purified water with Ventura’s existing water supply: The source of the water does not impact my comfort in drinking it.

7. Please rate the extent to which you agree/disagree with the following statements about blending advanced purified water with Ventura’s existing water supply: Free response.

Trust 4. How much would you say you trust Ventura Water to provide safe drinking water?

10a. The following is a list of people and organizations that may provide information about advanced purified water: Department of Public Health

10b. The following is a list of people and organizations that may provide information about advanced purified water: Local Business Owners

10c. The following is a list of people and organizations that may provide information about advanced purified water: Nutritionists

10d. The following is a list of people and organizations that may provide information about advanced purified water: Environmental Protection Agency (EPA)

10e. The following is a list of people and organizations that may provide information about advanced purified water: Residents of a community that have already implemented potable reuse

10f. The following is a list of people and organizations that may provide information about advanced purified water: Environmental organizations

10g. The following is a list of people and organizations that may provide information about advanced purified water: Independent lab researchers

Appendix 70

10h. The following is a list of people and organizations that may provide information about advanced purified water: Ventura Water Department

10i. The following is a list of people and organizations that may provide information about advanced purified water: Medical researchers

10j. The following is a list of people and organizations that may provide information about advanced purified water: The local newspapers

10k. The following is a list of people and organizations that may provide information about advanced purified water: Mayor of Ventura

10l. The following is a list of people and organizations that may provide information about advanced purified water: Local community leaders

10m. The following is a list of people and organizations that may provide information about advanced purified water: City Council members

10n. The following is a list of people and organizations that may provide information about advanced purified water: Scientists

10o. The following is a list of people and organizations that may provide information about advanced purified water: Taxpayer advocate organizations

10p. The following is a list of people and organizations that may provide information about advanced purified water: Medical doctors

10q. The following is a list of people and organizations that may provide information about advanced purified water: The agricultural community

10r. The following is a list of people and organizations that may provide information about advanced purified water: The local radio stations

10s. The following is a list of people and organizations that may provide information about advanced purified water: Professors at local universities

Safety 1. What water source do you consider the safest?

2. How often do you think about the safety of your drinking water?

7a. Please rate the extent to which you agree/disagree with the following statements about blending advanced purified water with Ventura’s existing water supply: I feel the water is clean enough to drink.

7c. Please rate the extent to which you agree/disagree with the following statements about blending advanced purified water with Ventura’s existing water supply: I feel satisfied that there is reliable monitoring throughout the treatment process.

Information 7b. Please rate the extent to which you agree/disagree with the following statements about blending advanced purified water with Ventura’s existing water supply: I feel other alternative water sources (e.g. desalination or imported water supplies) are preferable.

8a. How much would you support adding advanced purified water to Ventura's water supply if it would lead to the following benefits?:

Appendix 71

Advanced purified water will increase Ventura's overall drinking water supply.

8b. How much would you support adding advanced purified water to Ventura's water supply if it would lead to the following benefits?: Advanced purified water has a lower environmental impact than other alternative water supplies (e.g. desalination or imported water).

8c. How much would you support adding advanced purified water to Ventura's water supply if it would lead to the following benefits?:

8d. How much would you support adding advanced purified water to Ventura's water supply if it would lead to the following benefits?: Advanced purified water will improve Ventura's overall drinking water quality. 9a. How helpful would each of the following be for improving your perceptions and your community's perceptions of drinking advanced purified water in Ventura?: Education about the treatment process. 9b. How helpful would each of the following be for improving your perceptions and your community's perceptions of drinking advanced purified water in Ventura?: Scientists report that the treatment process is clean and safe.9c. How helpful would each of the following be for improving your perceptions and your community's perceptions of drinking advanced purified water in Ventura?: State Water Regulators report that the treatment process is clean and safe.9d. How helpful would each of the following be for improving your perceptions and your community's perceptions of drinking advanced purified water in Ventura?9e. How helpful would each of the following be for improving your perceptions and your community's perceptions of drinking advanced purified water in Ventura?: The opportunity to taste the advanced purified water.9f. How helpful would each of the following be for improving your perceptions and your community's perceptions of drinking advanced purified water in Ventura?: A positive track record showing the success and safety of potable reuse water in other areas.9g. How helpful would each of the following be for improving your perceptions and your community's perceptions of drinking advanced purified water in Ventura?: Economic benefits as compared to other water supply options.9h. How helpful would each of the following be for improving your perceptions and your community's perceptions of drinking advanced purified water in Ventura?: Environmental benefits as compared to other water supply options.

Demographic Correlations

11. What is your age? 12. You are: (M/F)13. Are there children (under 18 years) in your household? 14. Please specify you you ethnicity15. What is your combined annual household income? 16. What is your education level?17. What is your ZIP code?

Appendix 72

Appendix 6: Example Recommendation Synthesis

The following is an excerpt from the recommendation synthesis table, showing the number of themes the recommendation covers, the number of sources that stated the recommendation, which themes the recommendation covers, and the citations for each piece of literature that states that recommendation.

Appendix 73

Appendix 7: Ventura Demographics