Yarra Valley Water

Yarra Valley Water

Report for North Warrandyte Sewerage Backlog

Alternative Options Assessment

March 2012

31/284360/ 4/204335 North Warrandyte Sewerage Backlog Alternative Options Assessment

This North Warrandyte backlog Sewerage Alternative Options Assessment (“Report”):

1. has been prepared by [insert GHD entity which provides the Report – for example that entity may be GHD Pty Ltd or GHD Australia Pty Ltd] (“GHD”) for Yarra Valley water (YVW);

2. may only be used and relied on by [insert name of client];

3. must not be copied to, used by, or relied on by any person other than YVW without the prior written consent of GHD;

4. may only be used for the purpose of alternative options assessment (and must not be used for any other purpose).

GHD and its servants, employees and officers otherwise expressly disclaim responsibility to any person other than YVW arising from or in connection with this Report.

To the maximum extent permitted by law, all implied warranties and conditions in relation to the services provided by GHD and the Report are excluded unless they are expressly stated to apply in this Report.

The opinions, conclusions and any recommendations in this Report are based on assumptions made by GHD when undertaking services and preparing the Report (“Assumptions”).

GHD expressly disclaims responsibility for any error in, or omission from, this Report arising from or in connection with any of the Assumptions being incorrect.

Subject to the paragraphs in this section of the Report, the opinions, conclusions and any recommendations in this Report are based on conditions encountered and information reviewed at the time of preparation and may be relied on until 12 months, after which time, GHD expressly disclaims responsibility for any error in, or omission from, this Report arising from or in connection with those opinions, conclusions and any recommendations.


Contents

1. Introduction 1

1.1 Background 1 1.2 Options 2 1.3 Methodology 4

2. Water and Contaminant Balance 5

2.1 Seasonal Demand 5 2.2 Household Indoor Use 5 2.3 Grey and Black Water Generation 6 2.4 Grey Water Reuse Options 7 2.5 Black Water Reuse Options 7 2.6 Contaminant Balance 9

3. Regulatory Requirements 12

3.1 Legislative Requirements 12 3.2 Recycled Water Class 12 3.3 On-site Treatment Systems 13 3.4 Local STP and Recycled Water scheme 13 3.5 Buffer Distance Requirements 15

4. Options Review 17

4.1 Option 1 - Grey Water Treatment Systems 17 4.2 Option 2 - STEP / STEG 19 4.3 Option 3a - Local STP for Irrigation 20 4.4 Option 3b – Local STP and Recycled Water Plant for Class A Reuse21 4.5 Option 4 - On-Site Wastewater Treatment 24 4.6 Recommendation 26

5. Multi Criteria Assessment 27

5.1 General 27 5.2 TBL Assessment Results 27 5.3 Sensitivity Analysis 28

6. Life Cycle Analysis and Results 30

6.1 Characterisation 31 6.2 Normalisation 32


7. Economic Analysis 33

7.1 On-site Treatment Systems – Grey Water and All Waste 33 7.2 Income from Recycled Water 34 7.3 Net Present Cost and Net Present Value Analysis 35

8. Conclusion 37

Table Index Table 1 Alternative Options 2 Table 2 Key activities of Alternative Options Investigation 4 Table 3 Indoor Water End Use 5 Table 4 Average Daily Wastewater Flows 6 Table 5 Average Daily Residential Class A Demand 8 Table 6 Performance objectives and accepted uses of reclaimed water for

on-site treatment 13 Table 7 Recycled Water Quality Targets 13 Table 8 Class C Recycled Water Quality Targets 15 Table 9 Victorian Buffer Distances for sewerage works (<5000 EP) 15 Table 10 Summary of Grey Water Treatment Technologies Reviewed 17 Table 11 Grey water Unit Cost Summary 18 Table 12 STEP/STEG Cost Assumptions 19 Table 13 Percentage of suitable septic tanks 20 Table 14 STP Parameters 20 Table 15 Class A Treatment Train and Log Removals 22 Table 16 STP Location Comparison 23 Table 17 ‘All waste’ On-site Treatment Technology Summary 25 Table 18 Wastewater Unit Cost Summary 25 Table 19 TBL Assessment Scores 27 Table 20 On-site Wastewater Treatment Systems – Cost Assessment 33 Table 21 STP and Recycled Water Treatment Plant – Cost Assessment 33 Table 22 Recycled Water Storages – Cost Assessment 34 Table 23 Recycled Water Distribution System – Cost Assessment34


Figure Index Figure 1 North Warrandyte 1 Figure 2 Total Wastewater Generated by RAs 6 Figure 3 Grey water demand and produced 7 Figure 4 Contaminant Contribution 10 Figure 5 Average Contaminant Contribution by Option 11 Figure 6 TBL Assessment Scores 28 Figure 7 Sensitivity Analysis: MCA without NPC 29 Figure 8 Graphical Representation of LCA Results (Characterization). 31 Figure 9 LCA Normalisation Per Person 32 Figure 10 NPC / NPV per Property 35 Figure 11 NPC / NPV per Property including Customer Costs 36

Appendices A Greywater Treatment System Schematic B STEP/STEG Schematic C Local STP Schematic D Wastewater Treatment System Schematic E Stakeholder Correspondence F Potential Irrigation Areas in North Warrandyte G Open Space Locality Plan H Grey Water System Cost Summary I All Waste System Comparison J On-Site Systems Issues and Considerations K STP Cost Summary

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1. Introduction

1.1 Background The Yarra Valley Water (YVW) Sewerage Backlog Program aims to provide sewerage services to approximately 17,000 properties within its business area that are not currently connected to the sewerage system. The vast majority of these properties are currently using septic tank systems, many of which are no longer performing to acceptable environmental standards.

North Warrandyte (refer to Figure 1) is a suburban township 30 km north east from the centre of Melbourne with a population of approximately 2,650. North Warrandyte is predominantly a low-density residential area comprising medium and large lots ranging in size from 0.1 to 6 ha. The township is set on the northern banks of the Yarra River amongst hilly terrain densely populated with a wide variety of native and non-native vegetation. The habitat in the area supports a range of fauna, including species listed under the Flora and Fauna Guarantee Act. As well as the Yarra River, other listed features include Stony Creek and Pigeon Bank Gully.

Figure 1 North Warrandyte

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1.2 Options This report investigates alternative wastewater management options that could augment or replace a conventional wastewater collection system. YVW has identified four options that are listed in Table 1 and summarised below.

Table 1 Alternative Options

Option number Description

1 On-site grey water treatment systems for internal and external reuse

2 STEP / STEG system (in combination with conventional reticulated sewerage)

3a Local STP producing Class C water for public open space irrigation

3b Local STP / RWTP producing Class A water for residential use (internal and external) and Class C water for public open space irrigation

4 On-site ‘all waste’ treatment systems for external reuse

1.2.1 Option 1 - On-Site Grey Water Reuse

This option assumes lot scale domestic grey water treatment systems for external (i.e. garden watering) and internal (toilet flushing and laundry) use. The option requires a conventional reticulation system to discharge excess grey water during wet weather, and results in a reduction in potable water consumption and a seasonal reduction in wastewater flows.

Refer to Appendix A for a schematic of the grey water treatment system.

1.2.2 Option 2 - STEP / STEG

A Septic Tank Effluent Pumped (STEP) or Septic Tank Effluent Gravity system (STEG) utilises property septic tanks to provide retention and primary treatment of wastewater onsite prior to transfer to a conventional reticulation system for further treatment downstream. The requirement for maintenance of septic tanks remains, with a key influencing factor on this option’s effectiveness being the condition of existing septic tanks, and the requirement for septic tank upgrades.

Key benefits associated with STEP/STEG systems include a reduction in daily peak flows and the primary treatment of wastewater onsite. Refer to Appendix B for a schematic of the STEP/STEG system.

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1.2.3 Option 3 - Local Sewage Treatment Plant (STP) and Recycled Water

This option considers the construction of a local sewage treatment plant (STP) to provide Class A and Class C recycled water for internal and external reuse (including irrigation of open space). The key issues associated with this option include identification of an appropriate location for the STP and associated storages and identifying an appropriate discharge option for the treated effluent should that be required.

Two sub-options were developed for this option:

a) A recycling scheme supplying Class C water for irrigation of specified public space areas; and

b) A recycling scheme supplying Class A water for residential and commercial areas, as well as irrigation of specified public space areas.

Benefits associated with this option include a reduction in potable water demand, a greening of local open spaces and a reduction in the level of nutrients delivered to the downstream reticulated network.

Refer to Appendix C for a schematic of the local STP.

1.2.4 Option 4 - On-Site Wastewater Treatment

This option assumes that ‘all waste’, being black and grey water, is treated onsite for external use i.e. garden watering. As per the grey water treatment option, this reduces potable water use over the summer months. The main challenge with this option is the ability to retain flows within the property boundary, particularly during winter months and especially given the clay and rocky soil types that are anticipated within these reticulation areas.

The benefits associated with this option include a reduction in potable water demand and a reduction in the level of nutrients delivered downstream.

Refer to Appendix D for a schematic of the wastewater treatment system.

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1.3 Methodology This report details the findings of an investigation into each of these alternatives and the process that was undertaken to determine the feasibility of alternative wastewater methods for North Warrandyte. The key activities undertaken during this investigation are summarised below in Table 2.

Table 2 Key activities of Alternative Options Investigation

Activity Description

1 Completion of a water and contaminant balance for wastewater flows for each reticulation area.

2 Assessment of the system requirements, characteristics and cost of each option.

3 A Multi Criteria Assessment (MCA) of each option with a comparison of the options to the base case (that has been established in Part A of this project).

4 Life Cycle Assessment (LCA) of each option and a comparison of the options to the base case.

5 Economic analysis of each option using Net Present Value (NPV) that included an assessment of the financial impact of each option for YVW.

6 Discussion of outcomes and a recommendation of preferred technologies.

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2. Water and Contaminant Balance

To determine the water and contaminant balance for North Warrandyte a review of water consumption data for the reticulation areas (RA’s) was undertaken to estimate household water use by volume and domestic irrigation rates (to indicate sustainable irrigation rates and potential potable water savings).

Further assumptions were made regarding end use of water to estimate likely sewage loads and the proportion of grey and black water generated by each property.

Further review of demand data identified high water users in the area and potential non-potable irrigation opportunities.

2.1 Seasonal Demand Average household water demand over the year, for the 1,005 households within the North Warrandyte RA’s, is approximately 436 L/household/day based on recent consumption data provided by Yarra Valley Water1.

Analysis of the seasonal variation of water demand over the last 12 months indicates that demand varied between 485 L/household/day in summer and 401 L/household/day in winter. It is therefore assumed that outdoor water demand is up to 84 L/household/day or 17% of summer demand.

2.2 Household Indoor Use It has been assumed that winter water demand approximates indoor water use as irrigation is assumed to be minimal. On this basis, the percentage and volumetric breakdown of end uses shown in Table 3 has been drawn from a recent study undertaken by GHD using YVW data2.

Table 3 Indoor Water End Use

Use Percentage of Household Water Use

Resulting Wastewater Flows (L/household/day)

Shower (Grey Water) 35% 141

Clothes Washer (Grey Water) 19% 76

Total Grey Water 54% 217

Toilet (Black Water) 17% 68

Dishwasher (Black Water) 2% 8

Indoor Miscellaneous 27% 108

Total Black Water 46% 184

Total Water Demand 100% 401

1 Quarterley consumption data supplied by Peter Roberts (YVW) via email on the 16th December 2011 2 Smart Water Fund’s Melbourne Alternative Water Atlas Project (2011)

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2.3 Grey and Black Water Generation The total average daily wastewater flows generated in the RAs is shown in Table 4 based on data provided in Table 3.

Table 4 Average Daily Wastewater Flows

Average Daily Wastewater Flows (kL/day)

All Wastewater Grey water Black water

Combined RAs 401 217 184

Figure 2 below shows the estimated volume of wastewater (black and grey water) generated by each RA. The purpose of this estimation is to identify geographic concentrations of wastewater generation and potential reuse. It is evident that water consumption is concentrated in RA4993 due to the higher number of those lots in RA4993.

Figure 2 Total Wastewater Generated by RAs

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2.4 Grey Water Reuse Options Reuse options for grey water have been assumed to include toilet flushing, laundry and external irrigation. Toilet use and laundry account for 144 L/day (or 36%) of indoor consumption. This leaves an additional 73 L/day of grey water for outdoor use, slightly less than the estimated 84 L/household/day estimated in Section 2.1.

Therefore:

All grey water could potentially be reused on-site during summer months; and

Excess grey water will need to be diverted to sewer during winter months.

Figure 3 Grey water demand and produced

2.5 Black Water Reuse Options Three options for all wastewater reuse have been considered within this report.

1. Lot Scale Treatment and Reuse

Under this option it is assumed that the treatment of wastewater will be to a standard that is fit for external reuse (i.e. irrigation). This is based on past studies and an understanding of the water quality that can be expected from on-site all waste treatment systems (discussed further below). Based on the conclusions of Section 2.1, approximately 73 L/household/day of treated water may be used for irrigation of gardens during summer months; no irrigation is required during winter months due to the predicted rainfall in North Warrandyte. It is also assumed, based on an appreciation of the area’s steep, hilly terrain, clay soil types and historically high rainfall during winter months, that properties within North Warrandyte cannot retain their wastewater on site all year round.

Therefore it is assumed that a reticulation system will be required to collect excess wastewater, reducing the effectiveness of this option.

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2. North Warrandyte Class C Irrigation Scheme

The local irrigation scheme considered the irrigation of public open space, vineyards, parks and gardens within and around North Warrandyte as well as high individual water users (i.e. those consuming 1 ML/year or more).

For the purposes of this study, an area within a 2km radius of any proposed STP location, and on the North side of the Yarra River, was considered for irrigation. Open spaces beyond this area were not considered due to the likely cost and construction issues associated with constructing a pipeline through the hilly and densely vegetated landscape that typifies the North Warrandyte area.

Nillumbik Council was also consulted regarding the appropriateness of irrigation, responding that: “the vegetation in most of the reserves around North Warrandyte, Research and Kangaroo Ground is adapted to dry conditions, so the addition of regular irrigation would have a detrimental effect on the remnant vegetation which the area is known for.” (Refer to Appendix A for full correspondence).

Following the analysis of potential irrigation areas, the following conclusions were made:

No open spaces requiring irrigation were identified within a 2 km radius of the proposed STP location (RA5726, refer to Section 4.4.4 for a discussion regarding the preferred STP location) and on the North side of the Yarra River; and

Four open spaces within a 2 – 4 km radius of the proposed STP location, and on the North side of the Yarra River are noted below for further discussion, should an irrigation network of greater than 2km from the STP be preferred:

– Research Park;

– Eltham College of Education;

– Swipers Gully Vineyard; and

– Evalyn Country Estate.

It should be noted that these open spaces are beyond the RA’s being considered as part of this report.

Refer to Appendix F for irrigation details and Appendix G for an open space locality plan.

On this basis it has been concluded that a local irrigation network is not feasible, or worthy of further detailed investigation, due to the lack of suitable open spaces proximate to the proposed STP location.

3. North Warrandyte Class A Scheme

A North Warrandyte Class A scheme would notionally provide Class A water to satisfy toilet, laundry and garden watering demands. Potential internal use of 144 L/household/day year round plus 84 L/household/day for irrigation during summer months (being the assumed limit of available grey water).

Seasonal Class A demands for North Warrandyte are summarised in Table 5 below.

Table 5 Average Daily Residential Class A Demand

Average Daily Class A Demand (kL/day)

Winter Summer

All North Warrandyte RA’s 145 229

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2.5.1 Water Balance Results Summary

Average daily volume of wastewater generated within North Warrandyte is approximately 403 kL/day (218 kL/day of grey water and 185 kL/day of black water);

Household garden demand is assumed to be up to 84 L/household/day over summer months (or 84 kL/day across North Warrandyte);

Potential grey water or Class A demand is assumed to be 228 L/household/day in summer and 144 L/household/day in winter; and

No potential demand for Class C water for local irrigation areas has been identified.

2.6 Contaminant Balance A contaminant balance was undertaken for each alternative servicing option to determine the relative characteristics of wastewater produced, and the potential for each option to remove contaminants from the waste stream.

Contaminant data was sourced from Table 6 of the 2006 CSIRO report, “Sustainability of Alternative Sewerage and Water Servicing Options – Yarra Valley Water”. This report provides typical contaminant constituents of wastewater sourced from kitchen, bathroom, toilet and laundry, whilst providing removal rates of various treatments such as grey water and black water and on-site septic tanks.

2.6.1 Contaminant Balance Results Summary

The contaminant balance indicates that:

grey water contributes a greater hydraulic load than black water; and

blackwater provides a greater contaminant load than grey water.

Therefore, when the volume of grey water is reduced or removed from the wastewater stream the concentration of the contaminants increases, whereas removal of black water from the system through irrigation provides the greatest contaminant reduction of the options available.

The typical contaminant contribution by household is provided in Figure 4. The typical contaminants that affect the quality of water is:

TN – Total Nitrogen

TP – Total Phosphorus

TSS – Total Suspended Solids

BOD – Biological Oxygen Demand

COD – Chemical Oxygen Demand

K – Potassium

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Figure 4 Contaminant Contribution

Further observations include:

On-site grey water reuse increases contaminant concentrations due to the reduced hydraulic load;

STEP / STEG systems reduce contaminant loads due to the primary treatment provided on-site;

For local sewage treatment and recycled water plants, wastewater is expected to be typical residential wastewater prior to treatment and distribution through the recycled water network; and

On-site wastewater treatment only reduces contaminant loads during summer months, due to the onsite reuse of wastewater. The wastewater cannot be contained on site during winter months due to the rainfall, therefore the wastewater is diverted to sewer.

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The contribution of contaminant loads by household for each of the alternative options is provided in Figure 5. For example, we can observe that STEP/STEG significantly reduces the concentration of TSS discharged to a wastewater transfer system.

Figure 5 Average Contaminant Contribution by Option

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3. Regulatory Requirements

3.1 Legislative Requirements EPA Victoria and the Department of Human Services recommend that the following guidelines are referred to when investigating and implementing projects involving the use of recycled water:

Guidelines for Environmental Management Use of Reclaimed Water, Publication 464.2 (EPA Victoria, June 2003);

Guidelines for Environmental Management Recycling Schemes – Health and Environmental Risk Management, Publication 1015, October 2005;

Guide for the completion of a Recycled Water Quality Management Plan for Class A recycling schemes (DHS, October 2008); and

The Australian Guidelines for Water Recycling: Managing Health and Environmental Risk (Phase 1), (Natural Resource Management Ministerial Council, November 2006).

In addition to the above guidelines, a range of legislation, policies and guidelines are likely to apply to recycled water schemes, including:

Health Act 1958;

Environment Protection Act 1970;

EPA Licensing and Works Approval;

Code of Practice for On-site Wastewater Management Systems; and

Application form for Approval of On-site Wastewater Treatment Systems (http://www.epa.vic.gov.au /forms/default.asp#other).

3.2 Recycled Water Class The required level of treatment and the associated water quality objectives vary depending upon the nature of the end-use scheme. For a local STP and recycled water scheme in North Warrandyte, the appropriate recycled water class for each potential end use was determined. In summary, the potential local reclaimed water users and the associated recycled water class required, have been categorised as follows:

Irrigation of open spaces – Class C.

Residential reuse - Class A.

This section discusses the water quality requirements, and specific controls required for these end uses.

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3.3 On-site Treatment Systems For on-site grey water treatment systems and all waste treatment systems, the Victorian EPA Guidelines recommend treatment to a level as defined in Table 6, for the various end uses.

Table 6 Performance objectives and accepted uses of reclaimed water for on-site treatment

Parameter

(maximum value) Units Sub-surface

irrigation* Surface irrigation* Surface irrigation, toilet flushing and cold water laundry reuse**

Biochemical Oxygen Demand mg/L 20 20 10

Total Suspended Solids mg/L 30 30 10

E. Coli Org/100ml N/A 10 10

Treatment System Type All wastewater All wastewater Grey water only

*Source: EPA Victoria 2003 Publication 891

**Source: EPA ‘Code of Practice of On-site Wastewater Management Systems’.

3.4 Local STP and Recycled Water scheme

3.4.1 Class A Recycled Water – Performance Objectives and Accepted Uses

For recycled water end uses involving dual pipe recycling and unrestricted irrigation of open spaces, the Victorian EPA Guidelines recommend treatment to a level defined as Class A, which is outlined in Table 7. Endorsement of the recycled water scheme by the Department of Human Services (DHS) is also required in the form of endorsement of a Recycled Water Quality Management Plan (RWQMP), which is outlined in DHS’s Guide for the completion of a Recycled Water Quality Management Plan for Class A recycling schemes. The guidelines are designed to assist with selecting suitable treatment processes and treatment trains to achieve the required virus and protozoa log removals before supply to customers. There is also a requirement for on-going validation of each treatment process to provide an indication of the pathogen log removals (i.e. critical control points (CCPs)).

Table 7 Recycled Water Quality Targets

Parameter Victorian Guidelines

(Class A) National Guideline Targets*

Biochemical Oxygen Demand < 10 mg/L (Median)

Suspended Solids <5 mg/L (Median)

Turbidity <2 NTU (Median)

Chlorine Residual 1mg/L (Median)

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Parameter Victorian Guidelines

(Class A) National Guideline Targets*

Pathogen Reduction

E.coli <10 org./ 100mL

<1 Helminth per litre

7-log reduction in viruses

6-log reduction in pathogens

E.coli <1 org/100mL

105 log reduction in viruses

103.5 log reduction in pathogens

104 log reduction in bacteria

Acceptable uses – subject to site controls

Agricultural uses, urban (non-potable), and industrial uses.

Agricultural uses, urban (non-potable), and industrial uses.

Nutrient considerations are not a requirement for Class A water. Nutrient balances should be completed for irrigation applications to confirm that the amount of nutrients (e.g. nitrogen and phosphorus) applied by the reclaimed water application is not in excess of crop requirements.

*(Table 3.8 Municipal use – unrestricted access and application)

The National Guidelines utilise a risk management framework based on the hazard analysis and critical control point (HACCP) system used in the food industry. The framework involves proactively identifying and managing risks to control hazards to public health and the environment. These guidelines outline water quality objectives based on the recycled water use, indicative treatment process, on-site preventative measures and exposure reductions. The National Guidelines do not operate on a class-based system.

Based on the EPA Victoria water quality objectives and microbial criteria for Class A recycled water, the indicative advanced treatment process steps required to achieve the required log reductions include:

Secondary treatment with an activated sludge process;

Membrane Filtration / Ultrafiltration;

UV disinfection; and

Chlorine disinfection.

3.4.2 Class C Recycled Water – Performance Objectives and Accepted Uses

The Use of Reclaimed Water Guidelines (Publication 464.2) describes the level of treatment required for specified uses of reclaimed water, and the controls needed to manage the key risks associated with those uses. For local reuse in open spaces (with controlled public access) in North Warrandyte, Class C recycled water will be required, including secondary and pathogen treatment. If cattle grazing were to occur, helminth reduction would also be needed. Table 8 summarises the water quality targets associated with Class C recycled water.

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Table 8 Class C Recycled Water Quality Targets

Parameter Victorian Guidelines (Class C)

Biochemical Oxygen Demand

<20 mg/L

Suspended Solids <30 mg/L

Pathogen Reduction E.coli <1000 org/100 ml

Pathogen reduction (including Helminth reduction for Cattle grazing)

Acceptable uses

(Subject to site controls)

Agricultural, (except raw human food crops) and industrial uses.

For municipal schemes Class C reclaimed water may be used provided public access can be controlled by measures such as irrigation practices, restricted watering times (i.e. night time watering), fencing and/or withholding periods of at least four hours to ensure the areas are dry before access by humans.

3.5 Buffer Distance Requirements The Victorian guidelines for buffer zones for industrial residual air emissions (including sewage treatment plants) are set out in EPA publication AQ2/86 (EPA Victoria, 1990). The EPA bulletin excludes the following land uses from a buffer zone "residential areas (whether occupied or not), hospitals, schools, caravan parks and other similar uses involving the presence of individual people for extended periods, except in the course of their employment or for recreation”.

AQ2/86 recommends buffer distances for sewerage works related to installation treatment capacities below 1,000 equivalent population (EP); these are detailed in Table 9. The distances specified are subject to consultation with EPA, where wind regimes, topography, waste loading, treatment/disposal methods and design capacity should be taken into account.

Table 9 Victorian Buffer Distances for sewerage works (<5000 EP)

Type of installation (Treatment Capacity <1000 equivalent population)

Buffer distance (m) Distance from sensitive site (m)

Mechanical/Biological wastewater plants 200

Aerobic pondage systems 350

Facultative ponds 700

Disposal areas for secondary treated effluent:

(a) by spray irrigation

(b) by flood irrigation

200

50

Additional buffer distances are indicated in Section 7.1.2 of Publication 464.2 Use of reclaimed water (EPA Victoria, 2003b) for distances between application sites (irrigation area) and surface waters or sensitive developments (residential areas, public parks, schools and shops) in accordance with the class of irrigation water.

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Buffer distances to surface waters of 30m to 100m are recommended for Class C reclaimed water (depending on the irrigation type). It is noted that these buffer distances might be reduced under the following conditions:

Class A or B reclaimed water is used, the surface waters are seasonal or involve a drainage channel;

Best practice measures are implemented to prevent contaminated run-off leaving the site; or

The site is particularly favourable. Conversely the distances might need to be increased if Class D recycled water is used, the site is unfavourable, the surface water is highly sensitive or it is used for potable water supplies.

Buffer distances to the nearest sensitive development are suggested for spray irrigation applications as follows:

Class A reclaimed water quality – no buffer distances are prescribed due to the high microbiological water quality, however, irrigation should ensure no spraydrift or water movement off-site to avoid nuisance aspects of water; and

Class C reclaimed water quality – at least 30m from the edge of the wetted area to the nearest sensitive development.

The buffer distances sensitive to developments may need to be increased if high pressure spraying is conducted. The buffer distances may be reduced if suggested best practice measures are implemented to reduce spray drift.

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4. Options Review

4.1 Option 1 - Grey Water Treatment Systems A similar technology review of grey water treatment systems was undertaken for the Warrandyte Sewerage Backlog Project. Since that time one new system, ultraGTS Grey water Treatment System, has received EPA approval. We compared the new system to the Nubian Oasis grey water system and the NovaGrey treatment system (i.e. the preferred systems within the Warrandyte study).

In reviewing each system, the following is assumed:

Each grey water treatment system meets Victorian EPA regulatory performance objectives for surface irrigation and indoor use for toilet flushing and cold laundry washing;

Each system utilises a fixed media to enhance biological growth with the ability to cope with varying hydraulic loads;

The three grey water treatment system options do not require chemicals for disinfection, as they disinfect via UV; and

Each of the treatment systems provides visual and audible alarms to indicate failure of the electrical equipment and an overflow to sewer.

A summary of each unit’s characteristics is provided in Table 10 below.

Table 10 Summary of Grey Water Treatment Technologies Reviewed

Technology Advantages Disadvantages

Novagrey Domestic Grey water Treatment System

No commissioning fee

Chemical free process

Disinfection via flat sheet membranes and UV

Higher energy consumption

Requires an in ground sump

Nubian Oasis GT600 Disinfection via UV


Higher operational cost due to high annual servicing fee

Higher NPC

UltraGTS Grey water Treatment System

Disinfection via UV


Power cost reduced by ~25% since EPA approval

Requires an in-ground collection well

Higher service fee

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A summary cost comparison analysis has been undertaken and the results of the comparison are shown in Table 11. A more detailed breakdown is provided in Appendix H.

Table 11 Grey water Unit Cost Summary

Capital Cost (including installation but not customer plumbing)

Annual Service Charge

Electricity Cost NPC (assuming 25 year NPC period)

NovaGrey Treatment System $12,000 $270 $185 -$17,785

Nubian Grey water Treatment System $13,735 $462 $122 -$19,835

UltraGTS Greywater Treatment System $13,000 $848 $152 -$24,290

It has been assumed all systems have a service life of 15 years and all mechanical and electrical parts within these systems have an expected life of 5 years.

The Net Present Cost (NPC) is greater for the UltraGTS due to a larger annual service fee.

4.1.1 Recommended Grey Water Unit

The NovaGrey treatment system is the preferred option, based largely on the lower annual service charge associated with this system, as they all have a similar approximate capital cost.

4.1.2 Impact of Grey water use on Collection System

As part of the investigations into grey water reuse, the impact on the collection system was considered. Grey water reuse reduces volumes to sewer year round, and particularly during summer months. However, it is not possible to reduce the diameter of sewer mains in the collection system because:

During winter grey water will be discharged to sewer due to a reduction in the amount of grey water required for watering gardens;

The volume of water retained on-site for toilet flushing and laundry use is deemed to have negligible impact on sewer main requirements, so sewer mains need to continue to be able to cater for maximum flows from each property; and

It is possible that households may discontinue or reduce grey water reuse on-site meaning a collection system should be designed to cater for total wastewater flows from each property.

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4.2 Option 2 - STEP / STEG The first step in assessing the applicability of STEP/STEG systems across North Warrandyte was to estimate the condition of existing septic tanks. Data is yet to be received from Nillumbik City Council, regarding type and installation date of septic tanks. The average percentage of septic system failure in North Warrandyte RAs is therefore unknown.

Common reasons for septic tank failure include:

overland flow;

roots in pipes;

not desludged in the last 3 years;

outlet drain blockage;

leaking distribution pits; and

having greater than the required ecoli level.

If the outflow from the septic tank is contained on site via subsurface irrigation there is no testing of E.coli or BOD levels.

It is considered that septics installed greater than 20 years ago to be unsuitable for a STEP/STEG system, unless the septic tank was lined or replaced. In any case, it is difficult to test the integrity of the tank and the best (although expensive) alternative would be to line all septic tanks connected to a STEP/STEG system. The age of the septic system is a key consideration in assessing their suitability for a STEP/STEG system.

Costs associated with the STEP/STEG option have been developed with particular reference to the Kinglake West project, with a 2.5% inflation rate to factor in inflation between 2010 and 2012. Table 12 shows the cost estimate when 60% of the septic tanks require replacement.

Table 12 STEP/STEG Cost Assumptions

Item Number of Units Cost per Unit Total Cost

New Septic Tank - new tank for the STEP/STEP system 603 $10,250 $9,271,125

STEP/STEG Unit – Electricals/ pumps/ connection of STEP/STEG 1,005 $5,125 $5,150,352

Retrofitting – connecting existing septic tank to utilise a STEP/STEG system 402 $1,538 $618,075

TOTAL $11,949,450

For the purposes of this report, and assessing the STEP/STEG option, several scenarios were considered, as shown in Table 13.

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Table 13 Percentage of suitable septic tanks

Scenario Suitable septic tanks Percentage (%) Total Cost

1 201 20% $8,447,025

2 402 40% $10,198,238

3 603 60% $11,949,450

4 804 80% $13,700,663

5 1,005 100% $15,451,875

Further it is assumed that maintenance of the system is similar to that of a septic tank, requiring a service visit or desludging once every three years.

4.3 Option 3a - Local STP for Irrigation Option 3a consists of a local STP producing Class C recycled water for the irrigation of local parks, sports fields and open spaces with the excess treated effluent discharged to waterway. This option would require:

STP designed to achieve TN and TP removal;

Class C recycled water storage;

Recycled Water Pump Station; and

Distribution network to irrigation areas.

This option assumes that treated effluent in excess of recycled water demands can be discharged to the Yarra River. The adopted licence limits are the same as for other YVW STPs that already discharge to the Yarra River as outlined in Section 4.4.5. The activated sludge process has therefore been designed to achieve nitrogen removal with chemical dosing to remove phosphorus. Similar to other YVW plants discharging to the Yarra River, a sand filtration step (or equivalent) may also be required.

Table 14 STP Parameters

Parameter Median 90%ile

BOD (mg/L) 10 20

SS (mg/L) 10 20

Ammonia-N (mg/L) 5

Total N (mg/L) 10

Total P (mg/L) 1

E.coli (org/100ml) 200 1000

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4.3.1 Class C Irrigation Demand

Potential irrigation supply would be calculated based on:

Average inflow of wastewater of 403 kL/day;

Average rainfall data over year 2010 (from the BOM);

Crop irrigation factors appropriate for sports fields or equivalent; and

Potential irrigation areas as listed in Appendix F.

Variables in determining an irrigation volume include the actual area that could be irrigated (with the available water) and the winter storage volume. A sensitivity analysis would be performed using these variables with the aim of minimising both the number of days that the storage was empty and the number of days that storage capacity was exceeded.

There are no potential irrigation areas within a 2 km radius on the North side of the Yarra River, as described in Section 2.5 . Therefore there is no irrigation demand in Option 3a, consequently, a local STP producing Class C water for irrigation is not considered feasible within the scope of this investigation. The treatment requirements associated with Option 3a are expected to occupy a similar footprint to those of Option 3b described in Section 4.4.3.

4.4 Option 3b – Local STP and Recycled Water Plant for Class A Reuse This option includes additional treatment of the Class C effluent to a Class A standard to satisfy residential reuse demands (e.g. toilet flushing, cold laundry washing and garden watering). This option assumes that supply of Class A recycled water for reuse in a residential dual-pipe scheme is prioritised over Class C demands. This requires:

STP with ultrafiltration and UV disinfection to meet Class A water quality objectives;

Class A and Class C storages;

Recycled Water Pump Stations, for both Class A and Class C transfer; and

Distribution network to irrigation areas and residential areas.

This option also assumes that treated effluent in excess of recycled water demands can be discharged to the Yarra River as per Option 3a.

4.4.1 Demand

Residential recycled water demand for North Warrandyte was assumed to be 229 kL/day (summer) and 145 kL/day (winter) on average (as per Table 5). Assuming this is the priority and consistent demand, the remainder would be assigned to irrigation, via a similar methodology to that employed under Option 3a.

The results indicate that since there is no potential irrigation areas, Option 3b would require:

No winter storage;

No Class C treatment and storage tank;

No distribution network to irrigation areas;

A buffer storage of approximately 0.5ML; and

Approximately 70 ML/year of Class A recycled water being reused.

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4.4.2 Wastewater Treatment

The wastewater treatment requirements for Option 3b are similar to Option 3a, with the addition of an ultrafiltration step and chlorine disinfection for the removal of virus and protozoa required to achieve Class A (7-log virus and 6-log protozoa removal). The adopted Option 3b (Class A) treatment train is outlined in Table 15 below.

Table 15 Class A Treatment Train and Log Removals

Process Step Virus Removal (Log) Protozoa Removal (Log)

Inlet Works 0 0

ASP - Extended Aeration 0.5 0.5

Ultrafiltration 4 6

Ultra violet 1 3

Chlorine 2 0

Total Log Reduction 7.5 9.5

4.4.3 Footprint

A key constraint for this option (and Option 3a) is the siting of a STP and storage, and the associated social and environmental impacts of that location. Based on a concept prepared for a 0.35 ML/day (ADWF) treatment plant, a footprint of 4,000 m2 (62.5m x 62.5m) is assumed3. A storage volume of 0.5ML is required based on 53% of 3 x daily summer supply4.

This is based on budget proposals, and associated example photos provided to GHD for the construction of Class A UF treatment plants.

4.4.4 Option 3b – Preferred Treatment Location

Based on the footprints assumed above, possible sites for a treatment plant were investigated with the aim of locating it within open space, with a suitable buffer from residents and proximate to the Yarra River.

This proved a difficult task as undeveloped areas in and around North Warrandyte tend to be vegetated National Park or open space with significant community value. With this in mind, a notional site was identified, in Professors Hill Reserve to the south of RA5726. Constructing a STP in this reserve will be very challenging as it is full of vegetation, is used vastly by the community and therefore stringent planning permits will be required. A second proposed location would be on the Melbourne Water Depot site, however the shape of the land and steep terrain may prove difficult for construction. A plan showing the STP location and other open spaces is provided in Appendix G. The footprints shown in the plan are inclusive of both STP and storage footprint assumptions.

3 Based on a concept design for a 350kL/d MBR plant that has been recently constructed at Cradle Mountain. 4 As per Smart Water tank sizing assumptions

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Some pros and cons of each site considered are provided in Table 16.

Table 16 STP Location Comparison

Professors Hill Reserve Melbourne Water (MWC) Depot

Pros Proximate to residential water users

Relatively high compared to rest of study area

Proximate to residential water users

Near center of study area

May have less permits as it is MWC land

Cons Close to residents

Steep grade

Extremely vegetated

Close to residents

Steep grade

Extremely vegetated

Long and narrow property boundary

Following a review of each location, including a desktop review of the site conditions and restraints, the MWC depot location is considered too narrow to locate the STP within its boundary and it will pose significant construction and design issues. For that reason the Professors Reserve is preferred.

As a general comment, neither location stands out as being suitable. There are a number of reasons for this including limited buffer, private ownership of land or state park, nearby environmental values or steep slopes. For these reasons it is assumed to be unlikely that consideration of a treatment plant would progress to the next stage of planning and therefore no further discussion with Council has taken place regarding this option.

4.4.5 Environmental Risk

A land capability assessment should be undertaken to help identify the specific environmental hazards associated with recycled water schemes and to assist with the development of an environmental risk assessment. Key environmental risks that need to be considered include the impact of nutrients and salinity/sodicity.

The risk of over application of nutrients (e.g. nitrogen and phosphorus) is considered to be low because the WWTP process proposed for Options 3a and 3b includes nutrient removal to meet discharge requirements to the Yarra River (median concentration of 10 mg/L TN and 1 mg/L TP).

EPA Victoria Publication 464.2 advises that there is a risk of salinity impacts to groundwater, soil and crops when recycled water has a TDS concentration greater than 500 mg/L. The North Warrandyte catchment is primarily residential, and therefore the TDS is not expected to exceed this concentration.

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4.5 Option 4 - On-Site Wastewater Treatment Four ‘all waste’ treatment systems have received EPA approval since the Warrandyte backlog project recommended the Envirocycle Model 10NR as the preferred on-site wastewater treatment system. The four new systems are Aqua-Nova2000, FUJI Clean CE1500EX, WorkSmart and Wet Innovations Domestic.

This project compares the 10NR to all new EPA approved waste systems, based on the following criteria:

Footprint area (including any necessary buffer distances);

Chemical requirements;

Effluent quality achieved, including nutrient reduction;

Energy consumption; and

Capital and operating costs.

In considering this review the following should be noted:

long-term performance is difficult to assess, as there is very little data available on the effluent qualities achieved after a long period of use;

costs are for comparison purposes only and therefore should not be interpreted as complete; and

information relating to asset life is not definitive as yet, however, suppliers have been contacted directly to determine the life expectancy of the major parts of each unit where possible.

4.5.1 All Waste Treatment Technology Review

This section sets out the findings of the treatment technology review. In general:

Each of the ‘all waste’ systems reviewed is capable of achieving the EPA water quality requirements for surface irrigation. However, the processes for the ‘all waste’ systems reviewed vary from a conventional activated sludge plant, to an advanced membrane system, to a worm farm system. Therefore the effluent quality achieved varies;

Each of the systems require regular maintenance (up to 3-4 service calls per year) except WormSmart which requires maintenance once a year;

FUJI Clean CE1500EX and Aqua Nova 2000 treatment systems have chemical requirements for final chlorine disinfection;

Envirocycle Model 10NR, Wet Innovations Domestic and WormSmart systems achieve their final clarification without the use of chemicals; and

All of the treatment systems include visual and audible alarms to indicate failure of the electrical equipment; however the systems are not equipped with alarms or controls to identify water that does not meet its target water quality requirements.

‘All waste’ systems are intended for non-sewered areas and therefore are not intended to divert wastewater to the sewerage reticulation network during system failure or a high rainfall event. However, each manufacturer, except the WormSmart system, advised that their systems can be configured to overflow surplus wastewater (or treated wastewater).

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A comparison of the technologies is presented in Table 17.

Table 17 ‘All waste’ On-site Treatment Technology Summary

Technology Advantages Disadvantages

Envirocycle Model 10NR

Anaerobic digestion reduces biomass, and therefore the volume of sludge to be pumped out.

Final disinfection via UV.

Requires only 3 service calls per year.

Management of activated sludge system required.

Potential odour issues from the primary anaerobic processes.

Aqua Nova 2000

Completely automatic treatment process

System relies on physical, biological and chemical treatment

Requires upgrade every 2 years (High NPC)

FUJI Clean CE1500EX

UV – stabilised System relies on chemical treatment

WormSmart Aerobically decomposed by worms and micro-organisms

Annual inspection / service call

Lowest CAPEX and OPEX

Only installed in non-sewered areas

Try to use 100% biodegradable products

Additional drains to divert ground and stormwater

Wet Innovations Domestic

No chemical treatment

Lower BOD (g/day)

Unlimited life span

System to be desludged every 5 years (or as deemed necessary after inspection)

Appendix I provides further details on the all waste water treatment technologies reviewed.

Table 18 Wastewater Unit Cost Summary

Capital Cost (including installation but not customer plumbing)

Annual Service Charge

Electricity Cost NPC (assuming 25 year NPC period)

Envirocycle Model 10NR $23,000 $140 $ 300 -$28,264

Aqua Nova 2000 $14,000 $320 $175 -$23,797

FUJI Clean CE1500EX $12,800 $480 $108 -$19,910

WormSmart $11,600 $120 $21 -$14,105

Wet Innovations Domestic $13,390 $330 $184 -$17,716

Note: Envirocycle Model 10NR cost estimate is from the Warrandyte backlog project.

26


It has been assumed all systems have a service life of 15 years and all mechanical and electrical parts within these systems have an expected life of 5 years, unless otherwise specified by the supplier.

The Net Present Cost (NPC) is high for the AquaNova 2000 due to a more frequent electrical service requirement (every 2 years). The NPC is smallest for the WormSmart system due to the CAPEX and annual low service charge and energy use. The NPC for Wet Innovations Domestic is low due to the unlimited life span of the system.

4.6 Recommendation Based on the information tabled above, the WormSmart system is less costly than the other systems, however it is only to be installed in un-sewered areas and it is assumed that North Warrandyte residents may not favour this type of system as there is no simple overflow to sewer setup and failure of the system will possibly kill the worms if it is not rectified quickly. The preferred treatment technology is the Wet Innovations Domestic all waste treatment system as it involves low energy consumption, does not require chemicals for disinfection (final UV disinfection) and has an unlimited life span.

A further discussion on on-site treatment systems issues and considerations is provided in Appendix J.

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5. Multi Criteria Assessment

5.1 General A Multi Criteria Assessment (MCA) was undertaken for each alternative wastewater management option to identify a preferred option. The assessment was based on YVW’s TBL template produced for the Middle Yarra Backlog Strategy and considered the following assessment categories, consistent with YVW’s strategic intent:

Customer;

Environment;

Culture/Social; and

Efficiency (or NPC).

Sub-measures were considered under each of these categories, which were scored and weighted to enable comparison of the options considered.

The alternative option MCA scores range from +5 to –5 (with +5 being the best outcome) with 0 being assigned to the base case. The base case is the full pressure sewer system, which is the preferred concept design option.

GHD populated the MCA template initially with review and comments provided by Yarra Valley Water at the Value Management Workshop (VMW) on the 28th of February 2012.

5.2 TBL Assessment Results The TBL assessment was completed following YVW comments at the workshop using the agreed template together with information collected during the options assessment phase. Table 19 and Figure 6 present a summary of the results for each option, noting that the results for each option are relative to the Base Case (Pressure Sewer network as identified in Concept Design Report).

Table 19 TBL Assessment Scores

Category Option

1 2 3b 4 Base case

Customer -0.288 -0.212 -0.194 -0.370 0

Environment -0.122 0.000 -0.156 -0.342 0

Culture/Social -0.127 0.000 -0.107 -0.191 0

Efficiency -0.480 -0.240 -0.720 -0.480 0

Total Weighted Score -1.017 -0.452 -1.176 -1.383 0

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The MCA results indicate that Option 2, a STEP/STEG system is the preferred alternative option, followed by Options 1, 3b and 4. Option 2 scored the highest for the following reasons:

CO2 equivalent emitted per annum: The same amount and size of pumps as the ‘base case’, other options have a negative score due to large transfer pumps and treatment systems;

Construction Impact: construction of the STEP/STEG system is the same as ‘base case’;

Reduced risk to public health: Connection rate to the sewerage system is the same as ‘base case’, no extra risk of spill

Figure 6 TBL Assessment Scores

5.3 Sensitivity Analysis Given the negative influence of the Efficiency category on the final outcome, a sensitivity analysis removing the Efficiency category was undertaken, thus showing the preferred option when considering the customer, environment and culture/social categories.

Figure 7 shows the revised scores with Efficiency omitted.

Based on this scenario, Option 2 is again the preferred option. The improved performance of Option 2 under this scenario can largely be attributed to its high service level.

Base Case, 0.0

Option 1, -1.02

Option 2, -0.45

Option 3b, -1.18

Option 4, -1.38

-1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0

TBL Score

Opt

ion

29


Figure 7 Sensitivity Analysis: MCA without NPC

5.3.1 Summary

The results of the MCA indicate that the STEP/STEG system is the preferred alternative option with or without the inclusion of the efficiency category as shown in Figure 6 and Figure 7.

None of the alternative options are viable options. Options 1, 2 and 4 all require a reticulated sewerage system to be constructed (such as the Pressure Sewer System that has been identified as the Base Case), as well as their onsite systems to transfer excess wastewater off the property.

Option 3b, also requires a reticulation sewage system, such as the base case, along with a duplicate recycled water system to return the Class A water from the STP to the residents. Therefore all the alternative options result in more costly options; environmentally and socially.

Base Case, 0.000

Option 1, -0.537

Option 2, -0.212

Option 3b, -0.456

Option 4, -0.903

-1.0 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0.0

Score

Opt

ion

30


6. Life Cycle Analysis and Results

Life Cycle Analysis (LCA) considers the environmental impacts of each option from material sourcing and manufacture through construction and operation to enable a comparison that can assist the selection of the more environmentally sustainable option.

YVW uses Sima-Pro software and the Eco-Indicator 95 impact assessment method. Each option was broken down into its relative materials and construction methods used to build the option. This information was entered into the software program “SimaPro”, which split the option into the following categories:

Global warming;

Acidification

Eutrophication;

Heavy metals

Carcinogens;

Photo oxidant. Formation;

Pesticides;

Cumulative energy demand;

Water use; and

Solid waste.

The inputs of the different categories above were “characterised” to compare the impact of each option and demonstrate the impact that each option had on the environment.

The inputs were then “normalised” to compare the annual impact that each person in each option has against the average Australian person’s annual impact. This shows, in relative terms, which environmental indicator out of the list above is the most serious in relation to the project.

This contains the environmental indicators that YVW traditionally report on, namely:

Global warming. This is measured by the amount of carbon dioxide (Kg CO2) that is produced;

Eutrophication (Kg PO4). This is a measure of the degree of pollutant transfer to aquatic receiving waters and ecosystems;

Water Use. The volume of water (kL H20) used is also a key indicator of environmental impact; and

Solid Waste. The mass (kg) of solid waste that is produced is one of YVW’s measures of environmental impact.

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6.1 Characterisation The inputs were ‘characterised’ to illustrate the comparative impact of each option and the magnitude of each option’s impact on the environment. The graphs below provide a summary of the results where:

100% represents the “worst performing” option for that indicator; and

-100% is the “best performing” option.

Remaining options are assigned a percentage based on their impact relative to the “worst performing option”.

Figure 8 Graphical Representation of LCA Results (Characterization).

It can be observed that the All Waste system performs poorly in all but the ‘Water Use’ category. The STEP / STEG option, considering both a predominantly pressure and gravity network, performs best across all categories.

In general, the outcomes for each indicator of the LCA characterization can be attributed to the following aspects:

Global warming was influenced by on-site treatment plant energy consumption (for both grey and all waste systems) and wastewater treatment energy requirements;

Eutrophication was impacted by energy use, through the eutrophication impacts of brown coal excavation and combustion;

Water use results were due to volumes of water reused annually, and therefore the volumes of potable water assumed to be saved; and

Waste outcomes are due to the volume of excavation required and the size and depth of sewers.

-100.000

-80.000

-60.000

-40.000

-20.000

0.000

20.000

40.000

60.000

80.000

100.000

Global Warming Eutrophication Water Use Solid waste

Perc

enta

ge (%

)

Impact Category

On-Site Greywater

STEP / STEG - Pressure Network

STEP / STEG - Gravity Network

Option 3b - Warrandyte Class ANetworkAll Waste

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6.2 Normalisation The data outputs were also ‘normalised’ to compare the annual impact of each option to the impact that an average Australian has annually. This demonstrates, in relative terms, which environmental indicator out of the four is the most significant, or impactful, for each option.

Figure 9 LCA Normalisation Per Person Based on the normalised results for each option, the relative importance of each indicator to the overall environmental sustainability of the project is listed below in order of decreasing importance:

global warming,

eutrophication,

solid waste, and

water use.

-6.000

-5.000

-4.000

-3.000

-2.000

-1.000

0.000

1.000

2.000

3.000

4.000

Global Warming Eutrophication Water Use Solid waste

Perc

enta

ge (%

)

Impact Category

On-Site Greywater Treatment

STEP / STEG - Gravity network

STEP / STEG - Pressure network

Option 3b - Warrandyte Class ANetworkAll Waste

33


7. Economic Analysis

7.1 On-site Treatment Systems – Grey Water and All Waste Past backlog studies have shown that lot scale on-site treatment systems are often cost prohibitive with the main benefit being increased reuse of grey and black water and reduced potable water demand. Based on the two preferred on-site treatment systems reviewed in Section 4, the capital, operating and net present costs associated with installation of either a grey or ‘all waste’ treatment system are shown in Table 20 below.

Table 20 On-site Wastewater Treatment Systems – Cost Assessment

Option Capital Cost including installation ($,000)

Operational Cost ($,000 / annum)

NPC ($,000)

Grey water System

NovaGrey

$12.0 $0.46 -$17.8

All Waste System

Wet Innovations Domestic

$13.4 $0.51 -$17.3

As identified by the water and contaminant balance, installation of on-site wastewater treatment systems will also require collection systems as it is assumed that, particularly during wet periods, excess wastewater will need to be transferred from properties.

The preferred collection system was assessed and costed separately.

7.1.1 Centralised Treatment System

Cost estimates for the construction of a centralised STP were prepared for Options 3a (for information) and 3b. The outcomes are summarised in Table 21 below.

Table 21 STP and Recycled Water Treatment Plant – Cost Assessment

Option Treatment Plant Capital Cost ($,000)

Operational Cost ($,000 / annum)

3a Class C recycled water with nutrient reduction for discharge of treated effluent to the Yarra River

$2,900 $120

3b Class A recycled water with nutrient reduction for discharge of treated effluent to the Yarra River

$3,600 $150

A more detailed breakdown of this cost estimate is presented in Appendix K.

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7.1.2 Recycled Water Storage

A cost estimate was developed for the construction of a recycled water storage for Option 3b. These costs were based on previous GHD projects documented within GHD’s cost database. A conservative approach to costing storages was taken considering the limited space available, likely slope and rocky soil conditions.

Table 22 Recycled Water Storages – Cost Assessment

Option Storage Capacity (ML)

Capital Cost ($,000) Maintenance Cost ($,000 / annum) (@ 1% of capital)

3b 0.5 $250 (Class A) $2.5

7.1.3 Recycled Water Distribution System

Option 3a has no potential irrigation areas and therefore water distribution mains are not required.

Option 3b required a full Class A distribution network that was assumed to be equivalent to the length of pressure sewer mains, or approximately 83km. The cost of construction has been assumed to be $250/m based on estimates within GHD’s cost database.

Table 23 Recycled Water Distribution System – Cost Assessment

Option Capital Cost Operational Cost (@ 1% of capital) ($ / annum)

3b $20,750,000 $207,500

7.2 Income from Recycled Water Based on communications with YVW, we have assumed the following prices for recycled water in relation to Option 3b, where recycled water will be provided to the community:

Class A water: $1.53 / kL;

Annual Class A service charge of $21.08.

The income associated with these prices has been incorporated into the NPV for Option 3b, and was equivalent to annual income of $128,000.

35


7.3 Net Present Cost and Net Present Value Analysis A Net Present Cost (NPC) analysis was undertaken for Options 1, 2, 3b and 4, where there is no associated income to Yarra Valley Water. Also, customer costs e.g. on-site property plumbing, associated energy costs and maintenance costs have not been considered as part of the YVW NPC. Where revenue streams are created, an NPV calculation has been prepared.

The NPC and NPV assessments include the following:

NPC – capital and operating costs

NPV (options 3b) – capital, operating and revenue streams generated via the local recycled water scheme

Figure 10 below summarises the per lot NPV and NPC for each option.

Figure 10 NPC / NPV per Property

(25)

(20)

(15)

(10)

(5)

-

Opt

ion

1 - G

reyw

ater

- U

ltraG

TS

Opt

ion

2 - S

TEP

/ ST

EG

Opt

ion

3b -

STP

prod

ucin

g C

lass

A w

ater

Opt

ion

4-W

et In

nova

tion

Dom

estic

NP

V /

NP

C p

er lo

t ($,

000)

36


The results show the STEP/STEG option as being preferred.

An NPC and NPV analysis was undertaken that included costs borne by the customer, namely energy and service charges. The results are presented in the table below.

Figure 11 NPC / NPV per Property including Customer Costs This shows that the customer costs associated with Option 1, Option 2 and Option 4 that are associated with on-site treatment are significant.

The STEP/STEG option would be preferred, whether or not the customer costs are to taken into account, as shown in Figure 10 and Figure 11.

(30)

(25)

(20)

(15)

(10)

(5)

-O

ptio

n 1

- Gre

ywat

er -

Ultr

aGTS

Opt

ion

2 - S

TEP

/ S

TEG

Opt

ion

3b -

STP

pro

duci

ng C

lass

A w

ater

Opt

ion

4-W

et In

nova

tion

Dom

estic

NP

V /

NP

C p

er lo

t ($,

000)

37


8. Conclusion

An analysis of alternative wastewater management options has been undertaken to complement the design of a conventional collection system, and to investigate the potential to improve on the delivery of sustainable water and wastewater services in the Sewerage Backlog Areas of North Warrandyte.

Whilst each option exhibits some level of benefit, particularly from the point of view of reuse of wastewater, they all bring with them a significant financial cost that is unlikely to be warranted based on the volumes of water saved.

Some options, such as Option 3b proposing a local treatment plant, also bring significant community and environmental issues associated with siting that scale of infrastructure within, what is essentially, a small rural township.

Based on the analysis undertaken, the STEP/STEG option provides the greatest benefit, as assessed within the MCA, with the lowest NPC. This may suggest that the STEP/STEG option may be viable, particularly where there are not a large number of septic tanks requiring replacement. However given the nature of backlog works this is often not the case.

Based on the outcomes of the analysis, options 1, 3a and 4 are not recommended for implementation in North Warrandyte, due to:

Implementation of a collection system is required in all alternative options;

Higher cost than the base case as the alternative options are an addition to the base case; and

No suitable location for STP or local reuse areas;

Further investigation of the STEP/STEG option is recommended once the condition of the existing septic tanks and the ground conditions are confirmed. Installation of the pressure system would require excavation in rock on a slope or hilly surface, with difficult construction access to each property. The septic tanks are already in the ground and therefore minimal extra excavation will be required. The feasibility of installing the pressure system into the existing septic tank is also recommended to be investigated as this could decrease the excavation cost and construction difficulty of implementing the pressure system.

The results, and indeed previous work for Warrandyte, offer an insight into the conditions that will influence the likelihood of these alternatives being viable, acceptable and ultimately implemented. With this in mind it is proposed that in future the viability of alternative options could be assessed relatively quickly via a high level analysis looking at key factors that effectively rule in or out, individual options. More detailed analysis may then be dedicated to the ‘more’ viable options. This may also provide time to investigate options outside of those alternative options traditionally considered. For example, stormwater and rainwater harvesting, groundwater resources and integrating these with preferred sewerage servicing options.


Appendix A

Greywater Treatment System Schematic

Greywater from Bathroom and Laundry

Recycled water to House, Garden and Car washingWashing Machine Bath/Shower and

Handbasin

Process Line from Control Box

Toilet and Kitchen to SewerOverflow to Sewer

Toilet Kitchen Sink andDishwasher

RoadReserve

Sewer

Greywater Unit

Option 1 Onsite Greywater Reuse

BUILD

ING

LINE


Appendix B

STEP/STEG Schematic

Wastewater from Bathroom and Laundry

Washing Machine Bath/Shower andHandbasin


All Wastewater to SewerOverflow to Sewer


BUILD

ING

LINE

RoadReserve

Sewer

Option 2 STEP/STEG

Septic Tank

Toilet and Kitchen to Sewer

STEP Unit Pumps to Sewer STEG Unit Gravitates to Sewer


Appendix C

Local STP Schematic


Wastewater from Toilet and Kitchen

Pumps to Sewer

Kitchen Sink andDishwasher

BUILD

ING

LINE

RoadReserve

Sewer

Option 3 Recycled Water

On Site PressurePump Unit

Recycled water to House, Garden and Car washingToilet


Recycled Water



Appendix D

Wastewater Treatment System Schematic

Recycled water to House, Garden and Car washing



RoadReserve

Option 4 Onsite Wastewater Treatment Plant

BUILD

ING

LINE


WastewaterTreatment Unit

Wastewater from Toilet and Kitchen



Appendix E

Stakeholder Correspondence

Hi Camilla,

Of the list of reserves below, Research Park is the only one that is irrigated. It uses approximately 3500 kL each year. Professors Hill, Yarramie and Chase Reserves are environmental reserves so no irrigation is required. Kangaroo Ground oval is not irrigated and there are no plans for this to change.

Eltham College, Swipers Gully Vineyard and Evalyn Country Estate are not managed by Nillumbik Shire so you would probably need to approach them individually.

The vegetation in most of the reserves around North Warrandyte, Research and Kangaroo Ground is adapted to dry conditions so the addition of regular irrigation would have a detrimental effect on the remnant vegetation which the area is known for.

Regards,

Simon BonwickOpen Space Maintenance CoordinatorPhone: 9433 3501 Mobile: 0407 996 012

From: [email protected] [mailto:[email protected]] Sent: Tuesday, 20 December 2011 5:02 PMTo: Simon BonwickSubject: North Warrandyte Reserves

Hi Simon,

I'm working on a high level Alternative water reuse options assessment on behalf of Yarra Valley Water for the North Warrandyte backlog area.One of the options looks into irrigating open spaces with recycled water.Can you please send me some information on the uses and activities of the reserves and other open spaces in that area. The open spaces in the area I have been able to locate on google maps are:

RE: North Warrandyte ReservesSimon Bonwick to:[email protected]/12/2011 08:02 AMHide Details From: Simon Bonwick <[email protected]>

To: "[email protected]" <[email protected]>

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Professors Hill Reserve;Chase Reserve.Yarramie Park;Research Park; Etham College of Education;Kangaroo Ground Community Oval;Swipers Gully Vineyard; and Evalyn Country Estate.

If there are any I have missed, please feel free to add them to the list.

If the areas are currently being irrigated, what is the irrigation rate of the open spaces?If you have any information of the irrigation rate in the North Warrandyte area can you please advise me..

Regards

Camilla Bachet Civil Engineer - Wastewater & Recycling Systems

GHDT: 61 8687 8492 | V: 318 492 | [email protected] Lonsdale Street, Melbourne VIC 3000 Australia | http://www.ghd.com/

Water | Energy & Resources | Environment | Property & Buildings | Transportation

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This email, including any attachments, is confidential and intended only for the individual or the entity named. If you received this email in error please advise the sender immediately by return email and delete it and all copies from your system. If you are not the intended recipient of this email, you must not use, print,distribute,copy or disclose its contents to anyone.

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Appendix F

Potential Irrigation Areas in North Warrandyte

North Warrandyte Sewer Backlog ProjectAlternative Options AssessmentPotential Irrigation Areas

Name Unique Features Address Land Type Property Area (ha) Distance from Proposed STP

Research Park Park, Natural Features, Garden Products Main Rd Open Space, sports oval, Reserve 3.0 2km - 4kmEtham College of Education school ovals Main Rd 2 sports ovals, open space 4.0 2km - 4km

Swipers Gully Vineyard vineyard Main Rd vineyard 2.0 2km - 4kmEvalyn Country Estate Crops Main Rd crops 5.3 2km - 4km


Appendix G

Open Space Locality Plan

PROFFESSORS HILL RESERVE

RESEARCH PARK

ETHAM COLLEGE OF EDUCATION

SWIPERS GULLY VINEYARD

EVELYN COUNTRY ESTATE

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OPTION 3A AND 3BSTP AND IRRIGATION LOCALITY PLAN

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LEGENDPOTENTIAL IRRIGATION AREARECOMMENDED STP LOCATIONMWC DEPOTPOTENTIAL STP

mailto:[email protected]

http://www.ghd.com/


Appendix H

Grey Water System Cost Summary

GHD www.ghd.com.auTel. (03) 8687 8000 Fax. (03) 8687 8111180 Lonsdale Street Melbourne Vic 3000

North Warrandyte Park Backlog Sewerage On-site Greywater Treatment Systems Cost Estimate

Grey water System

NovaGrey Treatment System

Nubian Oasis UltraGTS

$9,735$2,000 $3,000

$12,000 $12,735 $13,000$270 $462 $848

$185 $122 $152$455 $584 $1,000

17,785-$ 19,835-$ 24,290-$

Electricity Cost0.15 $/kWh

kWh/yr Cost, $/yr kWh/yr Cost kWh/yr Cost473 $71 23 $3 8 $123 $3 14 $2 58 $9

422 $63 550 $83 650 $98237 $36 62 $9 140 $2131 $5 164 $25 160 $2445 $7

$185 $122 $152

Electricity costAnnual Operation and Maintenance Cost ($/annum)NPC (assuming 25 year NPC period)

NovaGrey Treatment System Nubian Oasis UltraGTS

Cost

Treatment system suppliedInstallation and CommissioningTotal Estimated Capital Cost per HouseMaintenance (by an approved maintenance contractor)

Option 1-GreywaterG:\31\2843604\Tech\Alternative Options\Cost Estimate\Cost Estimate_North Warrandyte.xls

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Appendix I

All Waste System Comparison

North Warrandyte Park Backlog Sewerage On-site Wastewater Treatment Systems Comparison

Wastewater SystemCriteria EnviroCycle 10NR AquaNova 2000 Fuji Clean WormSmart Wet Innovations Domestic

Description of Process

Anaerobic digestion, anaerobic filtration, aeration and fixed media

biological treatment and UV disinfection

Primary sedimentation, anareobic digestion, aerobic digestion, final

clarification and disinfection.

Primary sedimentation, anareobic filtration,

clarification and chlorine disinfection.

UV-stabilised, aerobically decomposed by worms

and micro-organisms

Primary sedimentation, ozofractionation, biological

aeration, foam fractationation, clarification.

BOD (mg/L) 10 20 20 - 20SS (mg/L) 10 30 30 - 30E-Coli (cfu/100ml) 1.6 10 10 - -Free residual chlorine (mg/L) - 0.2 - - -Footprint (m2) 4.7 9.46 3.61 - 5.76Energy Consumption (kWh/day) 2.5 3.2 2 0.4 3.4Operating controls to indicate failure of electrical equipment? yes yes yes yes yesService Calls per year 3 4 4 1 4COSTCAPEX 23,000$ 14,000$ 12,800$ 11,600$ 13,390$ OPEX 440$ 495$ 588$ 141$ 514$ NPC 28,264-$ 20,125-$ 19,910-$ 13,627-$ 17,716$

Cost EnviroCycle Model 10NR AquaNova 2000 FUJI Clean CE1500EX WormSmart Wet Innovations DomesticTreatment system supplied $12,000 $11,800 $8,000 $7,590Installation and Commissioning $2,000 $1,000 $3,600 $5,800Total Estimated Capital Cost per House

$23,000 $14,000 $12,800 $11,600 $13,390

Maintenance (by an approved maintenance contractor)

$320 $480 $120 $330

Electricity cost $175 $108 $21 $184Annual Operation and Maintenance Cost ($/annum)

$440 $495 $588 $141 $514

NPC (assuming 25 year NPC period) 28,264-$ 20,125-$ 19,910-$ 13,627-$ 17,716-$ Note: EnviroCycle 10NR details are from the Warrandyte Backlog project


Appendix J

On-Site Systems Issues and Considerations


On-site Treatment System Issues and Considerations

General There are a number of issues associated with the introduction of on-site grey water or “all waste” treatment systems in backlog areas. This section discusses these issues for the following systems, which were identified in this study as the preferred on-site wastewater treatment systems:

NovaGrey Treatment System; and

Wet Innovation Domestic All Waste Treatment System.

Ownership Scenarios One of the most important decisions YVW has to make is whether or not they should own and/or maintain these units. Two potential ownership models were considered:

YVW own and maintain units; or

Customers own and YVW maintain units.

YVW owns and/or maintains units: An opportunity exists for YVW to enter into a long-term supply arrangement with NovaGrey or Wet Innovations (or suppliers of an alternative system), which could also involve a reduced rate per unit depending on the number of units supplied. A decision would also be required in relation to who maintains them, and options may include:

Train YVW Sewer Operations Staff to maintain the units (a “maintenance trailer”, similar to the Pressure Sewer Spare Parts Trailer, could also be assembled and equipped with spare parts and tools);

Prepare a contract and provide training to YVW maintenance contractor, Bilfinger Berger Services (BBS) or an independent Plumbing Contractor; or

Develop an arrangement with NovaGrey and/or Wet Innovations who can provide local authorised representatives as required. This is the current maintenance arrangement for units that have been installed.

In accordance with the “EPA Publication 935 - Guidance on Applying for EPA Approval of an On-site Wastewater System”, municipal councils currently administer a permit system which regulates the installation, maintenance and monitoring of individual units at specific sites.

Furthermore, under these conditions, it is recommended that YVW’s GIS captures the properties that have installed on-site treatment units, the type and location. This will assist with YVW planning (e.g. future strategy work that may be required), sewer operations and maintenance crews.


Customer owns and maintains units Alternatively, YVW may prefer the customer to own and/or maintain these units. In this case YVW may recommend to customers that NovaGrey or Wet Innovations is their preferred supplier, and in doing so could develop a long-term agreement to supply the units at a reduced rate and also maintain them.

Under this model, the relevant Council’s GIS system would capture properties with on-site treatment units, as well as the type and location. YVW could request this information from Council, which would then assist YVW planning (e.g. future strategy work that may be required), sewer operations and maintenance crews.

Maintenance and Warranty Issues

NovaGrey Treatment System This system is accredited by the EPA, and the treated water may be used for surface irrigation, toilet flushing and cold water supply to washing machine. A condition of accreditation in Victoria is that this system receives regular maintenance by an approved service agent. Maintenance of the treatment and irrigation system is required every three months (as well as annual UV light bulb replacement).

If any component of the system fails during the warranty period then the owner can receive all labour/materials free of charge from the manufacturer provided the unit was installed and serviced by NovaGrey authorised representatives in accordance with the installation and servicing manuals.

The components of the treatment system at greatest risk of failure are:

Electrical components;

UV disinfection;

Pumps;

Blowers; and

Treatment column.

The unit has an audible and visual alarm system to indicate any electrical, blower and pump failures that may occur. The systems are also equipped with necessary controls for overflow to sewer, are independent of normal power supply and can be remotely monitored. By collecting data at some of these units YVW could gain a greater understanding of the unit reliability, how frequently they are used and the water use of certain fixtures in the household. However, this telemetry could be costly for YVW and/or the customer. In the absence of remote monitoring, the customer would be required to report any problems/failures etc.

Wet Innovations Domestic All Waste Treatment Unit This unit is approved by the EPA (up to 1,690L/day) which enables it to be installed in environmentally sensitive areas e.g. water catchment areas, rivers etc. Under the EPA guidelines, Wet Innovations Domestic treatment systems require inspection and maintenance every three months in accordance with the manufacturer’s specifications. Wet Innovations has the equipment and personnel available to maintain these systems and they are required to regularly check and service systems (under Wet Innovation’s ongoing maintenance agreement). Emergency call facilities are also available as part of this service. If effluent from the system is to be dispersed to land via subsurface irrigation, infiltration trenches, evapo-transpiration beds/trenches or a mound and samples of the effluent must be taken


where deemed necessary from the local council. Reports are delivered annually to the regulating bodies and local councils to comply with their conditions of approval.

At certain times of the year (wet, dry, power outages etc.) the customer will have to alter the valve configuration of the unit (i.e. divert to sewer or irrigation system depending on rainfall, climate and power outage). An irrigation area on the property is required to disperse the treated effluent and normally the customer is expected to maintain this area. Depending on lot size and slope, the pump operating levels can be set to ensure the volume reused for garden watering does not exceed the “sustainable volume” identified for the individual property size and slope and surplus treated wastewater will overflow to sewer.

The unit also contains a visual and audible alarm to indicate blower, pump and UV failure. Components of the system at greatest risk of failure include the anaerobic septic chamber, filter media, chambers, pump well and UV disinfection.

The Wet Innovations unit has a manufacturer’s warranty period of:

10 years guaranteed against structural default;

2 years for pumps; and

10 years for subsurface irrigation system against root intrusion or failure.

Therefore, if any of these components fail during the warranty period then the owner can receive all labour/materials free of charge from the manufacturer provided the unit was installed and serviced by Wet Innovations authorised representatives in accordance with the installation and servicing manuals.

Additional Regulatory Requirements (DHS, EPA, Council) Copies of the warranties and system service lives of these units have been provided to the EPA so that they could assess the ability of the systems to sustainably protect public health and environmental values over the operating life. Both of the units investigated have achieved accreditation.

According to EPA Publication 935 (Guidance on Applying for EPA Approval of an On-site Wastewater System) owners must also demonstrate to the EPA that they have developed operating and maintenance procedures that will allow their system to achieve the appropriate performance levels over its service life. To do this the installation manual, householder operating manual and serving manual must be provided so the EPA can assess whether appropriate procedures have been adopted.

DHS believe that “all waste” on-site wastewater systems are particularly high risk, as they have not undergone rigorous validation assessment to confirm that the system consistently meets the required water quality standard. DHS indicated that treated grey water (i.e. quality produced by UltraGTS system) is appropriate and may be used for toilet flushing and cold water supply to the laundry.

The EPA does not usually recommend the use of on-site systems where reticulated sewerage is available. However, an exception to this exists for wastewater schemes that incorporate a combination of on-site treatment and reuse, as well as a central collection and transfer systems (as investigated in this study), as this is a potentially sustainable solution to wastewater management in unsewered areas.


There are a number of publications covering further details on these issues, the application process, what the EPA have published or are planning to publish. Some of these documents are listed below:

Code of Practice for On-site Wastewater Management Systems

– This will cover dispersal methods, the review and approval process and that surface irrigation should be via drip or low-rise sprinklers only.

– Councils will be required to comply with these requirements when deciding whether an on-site system (EPA approved treatment system plus associated irrigation system) is appropriate to be used on a specific site.

EPA Publication 935 – Guidance on Applying for EPA Approval of an On-site Wastewater Treatment System.

EPA Publication 746.1 – Land Capability Assessment for On-site Wastewater Management

EPA Publication 747 – Approving Household On-site Wastewater Systems

EPA Publication 748 – EPA's Certificate of Approval System

EPA Publication 812.2 – Reuse Options for Household Wastewater

EPA Publication 760 – Guidelines for Aerated On-site Wastewater Treatment Systems

Application form for Approval of On-site Wastewater Treatment System

Construction Issues YVW should be aware of a number of risks associated with construction (e.g. possible cross connections) and ensure that necessary quality assurance measures are taken during construction to minimise the likelihood of these issues occurring. YVW must also ensure that customers, plumbers and suppliers are aware of these risks.

NovaGrey water Treatment System Installation is usually completed within one to two days and must be carried out by a trained accredited plumber. This ensures proper utility for the homeowner and meets Council regulations. During construction, the internal plumbing will also have to be reconfigured to separate treated grey water inflow to the house from the potable water inflow, and separate the grey water outflow to be treated from the raw sewage discharged to sewer. The system is designed to overflow to sewer, via an automatic diversion device, during periods of extreme flows or system failure, which reduces the required storage capacities. When demand is greater than supply an external control device coordinates the delivery of potable water to supplement the grey water supply. An approved irrigation system would also need to be installed to apply the treated grey water to the garden safely and appropriately. For each property installing these units a detailed land capability assessment is also recommended to avoid/minimise possible water logging and surface runoff. This assessment would involve an investigation of topography, soil features, groundwater, surface waters, climate etc. More information of the NovaGrey water treatment system is located on the website http://www.watergurus.com.au/novagrey

Wet Innovations Domestic All Waste Treatment Unit A flat site should be chosen and the tank should be placed on top of a 10cm layer of sand, located inside a hole in the ground (approximately: 1.8m deep and 3.2m2). Generally, the unit should be located no closer than 3m from the building and 3m from boundaries. Irrigation beds should be no closer than 1.5m from the unit and 1.5m from buildings and boundaries.


During construction the internal plumbing will have to be reconfigured to connect all property drains to the treatment unit. An approved irrigation system will also need to be installed to apply the treated “all waste” to the garden safely and appropriately. For each property installing these units a detailed land capability assessment is also recommended to avoid/minimise possible water logging and surface runoff. This assessment would involve an investigation of topography, soil features, groundwater, surface waters, climate etc. More information of the Wet Innovations Domestic “all water” treatment system is located on the website http://www.wetinnovations.com.au

Customer Education It is recommended that a customer information session be conducted and/or information packs provided prior to installing any units to ensure awareness of the risks associated with installing, maintaining and operating these units. YVW employees, UltraGTS and/or Wet Innovations representatives, Council representatives, prospective treatment unit owners and possibly licensed plumbers and irrigation company representatives would be encouraged to attend.

A number of topics should be discussed at the session, and also included in an information pack. Items to be addressed include:

A list of licensed plumbers for the customers to use. These plumbers should have had experience in the installation/maintenance of on-site treatment systems;

The treatment process applied in each unit;

The different materials, life expectancy and parts making up each unit;

The upfront and ongoing cost for each unit;

Why overflow to sewer is required and how the unit handles this feature;

What can and can’t be discharged from the household into the treatment units (e.g. rubbish, objects, certain hydraulic loads, chemicals, liquids, solids, detergents etc);

The operation and maintenance requirements (including estimated costs);

Advantages and disadvantages associated with the treatment units;

EPA and DHS guidelines and regulations;

Issues to consider in construction and installation (e.g. units, overflow to sewer, irrigation system, on-site plumbing, location, cross connections, decommissioning, construction footprint, likely timing, access requirements etc);

The manufacturer’s warranty details;

Service agreement details with the manufacturer or a service contractor acceptable to Council; and

Industrial and commercial applications which may require a higher frequency of maintenance, depending on the application.

Recommendation A common concern among sewer backlog customers is that decommissioning their septic tank means they won’t have wastewater to reuse on their garden anymore. Installing one of these units not only alleviates this concern but also means that a much higher quality of effluent is reused for garden watering. Depending on the nature of the agreement developed between YVW and the supplier there might also be an opportunity to discount the cost of the units. A reduction in unit price in conjunction with


a number of residents installing these units may also compel other residents in the township to do the same. It is likely that customers committed to the reuse of recycled water will also commit to the appropriate management and maintenance of the on-site treatment systems.

To meet EPA requirements, avoid complications and accelerate the process of installing and maintaining the units, it is recommended that YWV develop an agreement with an approved supplier for the installation and routine maintenance of the grey water units in North Warrandyte.

The option of installing systems for each property in all RAs considered in this project is not viable because the total cost is prohibitive and it is unlikely that all customers would be willing to pay for or maintain the units and there is no guarantee that all customers would use and maintain the on-site treatment units responsibly.


Appendix K

STP Cost Summary

GHD www.ghd.com.auTel. (03) 8687 8000 Fax. (03) 8687 8111180 Lonsdale Street Melbourne Vic 3000

YVW - Warrandyte Backlog - Alternative OptionsSTP Class A Cost Estimates

Plant Capacity ADWF 0.38 ML/dCAPITAL COST ESTIMATEDescription Quantity Unit Rate AmountSite establishment 80,000$ Inlet Works 1 Item -$ Package ASP 382 kL/d 740,000$ 740,000$ Clarifier 13 kL 100,000$ 100,000$ Sludge Tank 30 kL 5,000$ 10,000$ Chemical Dosing

CIP 1 Item 50,000$ 50,000$ Alum 2 kL 50,000$ 50,000$ MHL 10 L/d 50,000$ 50,000$

Ultrafiltration 0.38 ML/d 270,000$ 270,000$ UV Disinfection 10 L/s 65,000$ 65,000$ Hypo Dosing System 1 Item -$ Operations Building 1 Item 250,000$ 250,000$ Odour Control 780 L/s 140,000$ 140,000$ InvestigationsGeotech 20,000$ Planning/Approvals 50,000$ Building and civil works 1 No $170,000 170,000$ Commissioning + O&M 1 No $30,000 30,000$ Electrical 1 No $400,000 400,000$ Storage 1 No $250,000 250,000$ Distribution system 1 No $20,750,000 20,750,000$ Subtotal Estimated Capital Costs $23,480,000Project Contingency (30%) 30% $7,040,000Design and documentation (15%) 15% $3,520,000TOTAL ESTIMATED PROJECT COST $34,100,000OPERATIONAL COSTElectricity

Aeration 58,000 kWh/a 0.14$ 8,000$ Ultra-Filtration 15,000 kWh/a 0.14$ 2,000$ UV Disinfection 6,000 kWh/a 0.14$ 1,000$

Membrane Replacement 20,000$ 20,000$ Chemical Dosing (Alum + MHL) 11,000$ CIP 2,000$ 2,000$ Sludge Management 104 trips/a 120$ 25,000$ Civil Maintenance 1% % 18,314,400$ 180,000$ M&E Maintenance 5% % 12,209,600$ 610,000$ Storage 1% % 2,500$ 2,500$ Distribution system 1% % 207,500$ 207,500$

Subtotal Estimated Operating and Maintenance Costs $860,000NPC @ 2.5% over 25 years $39,600,000

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GHD

180 Lonsdale Street Melbourne, Victoria 3000 T: (03) 8687 8000 F: (03) 8687 8111 E: [email protected]

© GHD 2012

This document is and shall remain the property of GHD. The document may only be used for the purpose for which it was commissioned and in accordance with the Terms of Engagement for the commission. Unauthorised use of this document in any form whatsoever is prohibited.

Document Status

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Reviewer Approved for Issue

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S Tucker

19/3/12

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