Pilot Testing for Hexavalent Chromium Report - Pilot Testing for Chrome 6... · Pilot Testing for Hexavalent…

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<p>Pilot Testing for Hexavalent Chromium Removal</p> <p>Prepared for</p> <p>Cadiz, IncOctober 2016</p> <p> CH2M III </p> <p>Contents Section Page </p> <p>Acronyms and Abbreviations ............................................................................................................. vi </p> <p> Executive Summary ............................................................................................................. 1-1 1.1 What is the Cadiz Water Project? .................................................................................... 1-1 1.2 How Widespread is Hexavalent Chromium in Water? .................................................... 1-1 1.3 How is Chromium Removed from Drinking Water? ........................................................ 1-1 1.4 How does the RCF process work? .................................................................................... 1-2 1.5 Is there much experience with the RCF Process? ............................................................ 1-2 1.6 What is the treatment technology being investigated at Cadiz? .................................... 1-3 1.7 What does the Treatment System Cost for Hexavalent Chromium and Arsenic </p> <p>Removal? ......................................................................................................................... 1-5 </p> <p> Cadiz Water Project ............................................................................................................ 2-1 2.1 Introduction and Background .......................................................................................... 2-1 2.2 Conceptual Project Overview .......................................................................................... 2-1 2.3 Groundwater Quality ....................................................................................................... 2-2 </p> <p> Hexavalent Chromium and Arsenic in Groundwater ............................................................. 3-4 3.1 Introduction ..................................................................................................................... 3-4 3.2 Hexavalent Chromium Occurrence .................................................................................. 3-4 3.3 Hexavalent Chromium Water Quality Regulations .......................................................... 3-5 </p> <p>3.3.1 Federal Regulations ............................................................................................ 3-5 3.3.2 California Regulations ......................................................................................... 3-5 </p> <p>3.4 Treatment Alternatives for Hexavalent Chromium ......................................................... 3-5 3.4.1 In Situ Treatment .............................................................................................. 3-5 3.4.2 Ex-Situ Treatment ............................................................................................... 3-6 </p> <p>3.5 Arsenic Occurrence .......................................................................................................... 3-8 3.5.1 Arsenic Removal Treatment Alternatives ........................................................... 3-8 3.5.2 Conventional Filtration for Arsenic Removal ...................................................... 3-9 3.5.3 Potential for Simultaneous removal of Hexavalent Chromium and Arsenic .... 3-10 3.5.4 Proposed Treatment System for Pilot Testing .................................................. 3-11 3.5.5 Water Treatment Residuals .............................................................................. 3-17 </p> <p> Pilot Testing methods and Materials Groundwater Quality .................................................. 4-1 4.1 ATEC Pilot Equipment ...................................................................................................... 4-1 </p> <p> Pilot Testing Results ............................................................................................................ 5-1 5.1 ATEC Testing Objectives and Findings ............................................................................. 5-1 </p> <p>5.1.1 ATEC Testing Scenario 1 ...................................................................................... 5-1 5.1.2 ATEC Testing Scenario 2 ...................................................................................... 5-2 5.1.3 ATEC Testing Scenario 3 ...................................................................................... 5-4 5.1.4 ATEC Testing Scenario 4 ...................................................................................... 5-4 </p> <p>5.2 ATEC Overall Testing Results ........................................................................................... 5-6 5.2.1 Arsenic and Chromium Removal ........................................................................ 5-7 5.2.2 Iron Removal ..................................................................................................... 5-14 </p> <p>5.3 Filter Run Lengths .......................................................................................................... 5-15 5.4 ATEC Backwash Water Results ....................................................................................... 5-16 </p> <p>CONTENTS </p> <p>Section Page </p> <p> CH2M IV </p> <p> Conceptual Design of Facilities ............................................................................................ 6-1 6.1 Summary .......................................................................................................................... 6-1 </p> <p>6.1.1 Treatment System Options ................................................................................. 6-1 6.1.2 Water Delivery Options ...................................................................................... 6-1 </p> <p>6.2 Water Quality Standards.................................................................................................. 6-2 6.3 Conceptual Design Using ATEC System............................................................................ 6-3 </p> <p>6.3.1 ATEC System Operation and Design Criteria ...................................................... 6-4 6.4 Backwash Waste Flow Handling ...................................................................................... 6-5 </p> <p> Cost Estimates .................................................................................................................... 7-1 7.1 Costs for ATEC Systems Treatment .................................................................................. 7-1 7.2 Cost per Acre Foot ........................................................................................................... 7-2 </p> <p> References .......................................................................................................................... 8-1 </p> <p>Tables </p> <p>Table 1-1. Pilot Testing Treatment Results for ATEC Treatment System................................................... 1-5 Table 2-1. Summary of General Water Quality Parameters from Cadiz Wells .......................................... 2-3 Table 2-2. Preliminary Water Treatment Target Constituents .................................................................. 2-3 Table 3-1. Treatment Alternatives for Hexavalent Chromium .................................................................. 3-6 Table 3-2. Comparison of Arsenic Removal Technologies ......................................................................... 3-8 Table 3-3. Surveyed Systems ATEC Iron and Manganese Facilities ......................................................... 3-11 Table 3-4. Comparison of Pilot Removal Efficiency and Full Scale Removal Efficiency in Manganese Dioxide Media Filters ............................................................................................................................... 3-12 Table 3-5. Project Construction Components for Surveyed ATEC Water Treatment Systems ................ 3-14 Table 3-6. Capital Costs of ATEC Water Treatment Surveyed Systems, Escalated to 2016 Dollars ........ 3-15 Table 3-7. Annual Operations and Maintenance Costs Report for ATEC Systems, in 2016 dollars ......... 3-16 Table 4-1. Physical Characteristics of Filter Tanks and Media ................................................................... 4-3 Table 4-2. Pipe Configurations for Varying Contact Times ........................................................................ 4-4 Table 5-1. Pilot Testing Treatment Results for ATEC Treatment System................................................... 5-7 Table 6-1. Maximum Design Flow Rates .................................................................................................... 6-2 Table 6-2. Estimated Backwash Waste Volumes, mgd .............................................................................. 6-5 Table 6-3. Dry Weight Solids Produced Per Year ....................................................................................... 6-5 Table 7-1. CAPEX Estimates for ATEC System for 10-month Operating Period ......................................... 7-1 Table 7-2. CAPEX Estimates for ATEC System for 11-month Operating Period ......................................... 7-1 Table 7-3.OPEX Comparison for Treatment Systems................................................................................. 7-1 Table 7-4: Cadiz Treatment Costs Per Acre-Foot ....................................................................................... 7-2 </p> <p>Figures </p> <p>Figure 1-1. Hexavalent Chromium Removal with Reduction/Coagulation/Filtration (RCF) Process ......... 1-2 Figure 1-2. Hexavalent and Total Chromium Concentrations from 2005 through 2012 after Microfiltration ............................................................................................................................................ 1-3 Figure 1-3. ATEC Pilot Filter Schematic ...................................................................................................... 1-4 Figure 2-1. Google Earth Image Showing Conceptual Location of Water Treatment, Ag Wells, High Wells and Transmission Route to the Colorado River Aqueduct. ........................................................................ 2-2 Figure 3-1. Hexavalent Chromium Removal with Reduction/Coagulation/Filtration Process .................. 3-7 </p> <p>CONTENTS </p> <p>Section Page </p> <p> CH2M V </p> <p>Figure 3-2. Hexavalent and Total Chromium Concentrations from 2005 through 2012 after Microfiltration. ........................................................................................................................................... 3-7 Figure 3-3. Influence of Coagulant Dose, Arsenic Type and pH on Arsenic Removal .............................. 3-10 Figure 4-1. ATEC Pilot Filter Schematic ...................................................................................................... 4-1 Figure 4-2. ATEC Pilot Filters within the Trailer ......................................................................................... 4-2 Figure 4-3. Pipe Line Reactor Segments .................................................................................................... 4-2 Figure 4-4. Venturi Eductor and Bypass Pipe ............................................................................................. 4-3 Figure 4-5. A 47 mm Diameter Filter Shows the PrecipitatedIiron Collected from a Prefilter Ssample during the Pilot Test at Cadiz, 8/25/2015 .................................................................................................. 4-5 Figure 5-1. ATEC Pilot Testing August 25, 2015 Time Series ...................................................................... 5-2 Figure 5-2. ATEC Pilot Testing Hexavalent Chromium and Arsenic Removal at Various Ferrous Chloride Doses, August 25, 2015 .............................................................................................................................. 5-2 Figure 5-3. ATEC Pilot Testing August 27, 2015, Time Series ..................................................................... 5-3 Figure 5-4. ATEC Pilot Testing September 9, 2015, Time Series ................................................................ 5-3 Figure 5-5. ATEC Average Hexavalent Chromium Removal at Varied Contact Times ............................... 5-4 Figure 5-6. ATEC Run 1, November 19, 2015, Time Series ........................................................................ 5-5 Figure 5-7. ATEC Run 2, November 19 to 20, 2015, Time Series ............................................................... 5-5 Figure 5-8. ATEC Hexavalent Chromium and Arsenic Removal at Various Ferrous Chloride Doses, November 19 to 20, 2015 .......................................................................................................................... 5-6 Figure 5-9. Hexavalent Chromium and Arsenic Removal at Various Ferrous Chloride Doses ................. 5-14 Figure 5-14. Run 1, November 19, 2015 Iron Removal ............................................................................ 5-15 Figure 5-12. September 9, 2015 Iron Removal ........................................................................................ 5-15 Figure 5-10. August 25, 2015 Iron Removal ............................................................................................. 5-15 Figure 5-11. August 27, 2015 Iron Removal ............................................................................................. 5-15 Figure 5-13. September 10, 2015 Iron Removal ...................................................................................... 5-15 Figure 5-15. Run 2, November 19, 2015 Iron Removal ............................................................................ 5-15 Figure 5-16 Floating Decant with Plate Settlers, used for backwash clarification. ............................... 5-17 </p> <p> CH2M VI </p> <p>Acronyms and Abbreviations g/L micrograms per liter </p> <p>AF acre feet </p> <p>AFY acre feet per year </p> <p>As arsenic </p> <p>ATEC ATEC Water Treatment Systems </p> <p>ARZC Arizona and California Railroad </p> <p>CH2M CH2M Engineers, Inc. </p> <p>Cr chromium </p> <p>Cr+6 hexavalent chromium </p> <p>CRA Colorado River Aqueduct </p> <p>Fe iron </p> <p>GMMMP groundwater management, monitoring and mitigation plan </p> <p>gpm gallons per minute </p> <p>gpm/sf gallons per minute per square foot </p> <p>MAF million acre feet </p> <p>mgd million gallons per day </p> <p>mg Fe2+ milligrams of ferrous iron </p> <p>mg/L milligrams per liter </p> <p>mg O2 milligrams of oxygen </p> <p>Mn manganese </p> <p>MET Metropolitan Water District of Southern California </p> <p>psi pounds per square inch </p> <p>RCF reduction, coagulation, filtration </p> <p>slpm standard liters per minute </p> <p>TCLP toxicity contaminant leachate potential </p> <p>WET waste extraction test </p> <p>SECTION 1 </p> <p> CH2M 1-1 </p> <p> Executive Summary The State of California has developed a maximum contaminant level (MCL) for hexavalent chromium, also referred to as chromate or Chrome (VI) in dri...</p>

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