Source Options Assessment for the Metropolitan Supply
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In association with | Introduction |
Source Options Assessment for the
Metropolitan Supply
Purified Recycled Water Scheme Concept Report
Prepared for Watercare Services Ltd
Prepared by Beca Limited
8 December 2020
Creative people together transforming our world
| Source Options Assessment for the Metropolitan Supply |
Revision History
Revision Nº Prepared By Description Date
0 Francesca Nicklin Draft for client review 10/11/2020
With inputs from:
Vasu Veerapaneni and
Ian Law (process)
Dan Dwyer / Logan
Thomson (civil)
Do Van Toan / Bevan
Hill (geotechnical)
Leon Keefer / Jenny
Vince (planning)
Stephen Salmon
(power)
Carl Viljoen (cost)
1 Lorraine Marais Updated with 1/12/2020
comments received
from WSL and
Simpson Grierson
2 Francesca Nicklin Final 8/12/2020
Document Acceptance
Action Name Signed Date
Prepared by Francesca Nicklin / 8/12/2020
Lorraine Marais
Reviewed by Andrew Watson 8/12/2020
Jon Reed
Approved by Clive Rundle 8/12/2020
on behalf of Beca Limited
© Beca 2020 (unless Beca has expressly agreed otherwise with the Client in writing).
This report has been prepared by Beca on the specific instructions of our Client. It is solely for our Client’s use for the purpose for which it is intended in accordance
with the agreed scope of work. Any use or reliance by any person contrary to the above, to which Beca has not given its prior written consent, is at that person's own
risk.
Waikato River Water Take and Discharge Proposal – Board of Inquiry | i
| Source Options Assessment for the Metropolitan Supply |
Contents
1 Introduction ................................................................................................ 1
1.1 Introduction ............................................................................................................................ 1
1.2 Background............................................................................................................................ 2
1.3 Purpose of this report ............................................................................................................ 4
2 Regulatory Framework .............................................................................. 5
2.1 New Zealand Context ............................................................................................................ 5
2.2 Global Application .................................................................................................................. 5
2.3 Validated Pathogen Log Removal Values (LRVs)................................................................. 8
2.4 Observations and Conclusions .............................................................................................. 9
3 Indirect Potable – Campbell Road Storage Lake Option 3 (No
Surface Abstraction) Scheme................................................................. 11
3.1 Scheme Overview ............................................................................................................... 11
3.2 Rosedale AWTP Process Design Basis .............................................................................. 12
3.3 Campbell Road WTP Process Design Basis ....................................................................... 17
3.4 Transmission Design Basis ................................................................................................. 18
3.5 Site Summary – AWTP ........................................................................................................ 23
3.6 Site Summary – Campbell Road Storage Lake ................................................................... 31
3.7 Site Summary - Campbell Road WTP ................................................................................. 36
3.8 Transmission Routes and Schnapper Rock Reservoir ....................................................... 42
4 Direct Potable – Rosedale Scheme ........................................................ 44
4.1 Scheme Overview ............................................................................................................... 44
4.2 Process Design Basis .......................................................................................................... 45
4.3 Transmission Design Basis ................................................................................................. 45
4.4 Site Summary ...................................................................................................................... 48
5 Direct Potable – Mangere Scheme ......................................................... 49
5.1 Scheme Overview ............................................................................................................... 49
5.2 Process Design Basis .......................................................................................................... 50
5.3 Transmission Design Basis ................................................................................................. 51
5.4 Site Summary ...................................................................................................................... 51
6 Operating costs ....................................................................................... 56
7 Capital cost .............................................................................................. 57
7.1 Summary ............................................................................................................................. 57
7.2 S2: Indirect potable - Campbell Rd Storage Lake Option 3 (no surface abstraction) ......... 58
7.3 O2: Direct potable - Rosedale ............................................................................................. 60
7.4 O2: Direct potable - Mangere .............................................................................................. 61
8 Risk and assumptions ............................................................................. 63
Waikato River Water Take and Discharge Proposal – Board of Inquiry | ii
| Source Options Assessment for the Metropolitan Supply |
Appendices
Appendix A – Recycled Water Literature References
Appendix B – Transmission Concept Long Sections
Appendix C – Rosedale WWTP Population and Flow Forecasts
Tables
Table ES-1: AWTP plant capacity ........................................................................................................... ix
Table ES- 2: CAPEX cost estimate for 75MLD and 150MLD Facilities. Values in NZD millions
($,000,000) ............................................................................................................................................ ix
Table ES- 3: OPEX Cost Estimate ($/annum)..........................................................................................x
Table 2-1: Validated Pathogen LRVs ...................................................................................................... 8
Table 3-1: Rosedale AWTP Capacity .................................................................................................... 13
Table 3-2: Feed effluent parameters ..................................................................................................... 15
Table 3-3: Pipe Route Conveyance Options ......................................................................................... 19
Table 3-4: Pipe Route Conveyance Options ......................................................................................... 22
Table 3-5: Example AWTP footprints .................................................................................................... 23
Table 3-6: Planning assessment – key matters .................................................................................... 27
Table 3-7: Campbell Road storage lake planning assessment - key issues ......................................... 33
Table 3-8: Future considerations for the design of the Campbell Road WTP ....................................... 37
Table 3-9: Campbell Rd WTP planning assessment ............................................................................ 39
Table 5-1: Mangere AWTP Capacity ..................................................................................................... 50
Table 5-2: Mangere AWTP – expected planning requirements ............................................................ 53
Table 6-1: OPEX Cost Estimates for 75MLD and 150MLD Facilities - S2: Indirect potable - Campbell
Rd Storage Lake Option 3 (no surface abstraction) .............................................................................. 56
Table 6-2: OPEX Cost Estimates for 75MLD and 150MLD Facilities - O2: Direct potable - Rosedale 56
Table 6-3: OPEX Cost Estimates for 75MLD and 150MLD Facilities - O2: Direct potable - Mangere . 56
Table 7-1: CAPEX cost estimate for 75MLD and 150MLD Facilities. Values in NZD millions
($,000,000) ............................................................................................................................................ 57
Table 7-2: CAPEX cost estimate for 75MLD and 150MLD Facilities - S2: Indirect potable - Campbell
Rd Storage Lake Option 3 (no surface abstraction) .............................................................................. 58
Table 7-3: CAPEX cost estimate for 75MLD and 150MLD Facilities - O2: Direct potable - Rosedale . 60
Table 7-4: CAPEX cost estimate for 75MLD and 150MLD Facilities - O2: Direct potable – Mangere . 61
Waikato River Water Take and Discharge Proposal – Board of Inquiry | iii
| Source Options Assessment for the Metropolitan Supply |
Figures
Figure ES-1: Proposed Scheme for indirect potable purified recycled water Rosedale AWTP to
Campbell Rd Storage Lake (no surface abstraction) – Block Diagram .................................................. vii
Figure ES-2: Proposed Scheme for direct potable purified recycled water at Rosedale – Block
Diagram ................................................................................................................................................. viii
Figure ES-3: Proposed Scheme for direct potable purified recycled water at Mangere– Block Diagram
............................................................................................................................................................... viii
Figure 1-1: How this Purified Recycled Water Scheme Concept Report feeds into the overall options
assessment process in the “Water Source Options Alternative Assessment for the Metropolitan
Supply” report .......................................................................................................................................... 4
Figure 2-1: Purified Recycled Water Scenarios ...................................................................................... 6
Figure 2-2: Examples of AWTP Treatment Trains. Note all product streams are chlorinated. .............. 7
Figure 3-1: Proposed Scheme for Rosedale AWTP to Campbell Rd Storage Lake – Block Diagram . 11
Figure 3-2: Proposed Scheme for Rosedale AWTP to Campbell Rd Storage Lake – Aerial ................ 12
Figure 3-3: Typical RO based process flow diagram for an AWTP ...................................................... 14
Figure 3-4: Proposed Pipe Route – Rosedale AWTP to Campbell Rd Storage Lake........................... 18
Figure 3-5: Option 1 – 1 Pump Station .................................................................................................. 19
Figure 3-6: Option 2 – 2 Pump Stations ................................................................................................ 19
Figure 3-7: Proposed Pipe Route – Campbell Rd WTP to Schnapper Rock Reservoir ....................... 21
Figure 3-8: Option 1 – 1 Pump Station at start of pipe route................................................................. 22
Figure 3-9: Option 2 – 1 Pump Station midway along pipe route.......................................................... 22
Figure 3-10: Proposed Site – Aerial ...................................................................................................... 23
Figure 3-11: Proposed Site – Considerations ....................................................................................... 24
Figure 3-12. Planning map with overlays and aerials taken from Auckland Council’s GeoMaps
(October 2020). Watercare-owned land is outlined in yellow. .............................................................. 26
Figure 3-13: Transpower transmission network October 2020 ............................................................. 30
Figure 3-14. Planning map with overlays and aerials taken from Auckland Council’s GeoMaps
(October 2020). ..................................................................................................................................... 32
Figure 3-15. Water Supply Management Area (dark blue overlay) with underlying streams and flow
paths (light-blue). ................................................................................................................................... 33
Figure 3-16: Locality Plan - Campbell Road WTP ................................................................................ 36
Figure 3-17: Campbell Rd WTP potential sites - Contours ................................................................... 36
Figure 3-18: Campbell Rd WTP potential sites - Aerial ......................................................................... 37
Figure 3-19. Potential WTP locations shown with relevant planning overlays from AUP:OP. ............. 39
Figure 4-1: Proposed Scheme for direct potable purified recycled water at Rosedale – Block Diagram
............................................................................................................................................................... 44
Waikato River Water Take and Discharge Proposal – Board of Inquiry | iv
| Source Options Assessment for the Metropolitan Supply |
Figure 4-2: Proposed Scheme for direct potable purified recycled water at Rosedale WWTP – Aerial 45
Figure 4-3: Proposed Pipe Route – Rosedale AWTP to Schnapper Rock ........................................... 46
Figure 4-4. Proposed pipeline alignment (in yellow) between Rosedale Plant and the future
Schnapper Rock Reservoir (Designation 9301). Significant Ecological Areas (SEAs) identified under
the AUP:OP are shown in green hatching. ............................................................................................ 48
Figure 5-1: Proposed Scheme for direct potable purified recycled water at Mangere – Block Diagram
............................................................................................................................................................... 49
Figure 5-2: Proposed Scheme for direct potable reuse at Mangere RRF – Aerial ............................... 50
Figure 5-3: Mangere AWTP potential sites - Aerial ............................................................................... 52
Waikato River Water Take and Discharge Proposal – Board of Inquiry | v
| Source Options Assessment for the Metropolitan Supply |
Abbreviations and Definitions
Abbreviations Definitions
AUP:OP Auckland Unitary Plan: Operative in Part
AGWR Australian Guidelines for Water Recycling
AWTP Advanced Water Treatment Plant
CCPP Calcium Carbonate Precipitation Potential
CIP Clean in Place
DAF Dissolved Air Flotation
DWSNZ Drinking Water Standards for New Zealand
ECBF East Coast Bays Formation
GL Giga Litres
LSI Langelier Saturation Index
MAV Maximum Acceptable Value
MF Microfiltration
MLD Mega Litres per Day
OC Onerahi Chaos Series
RO Reverse Osmosis
RRF Resource Recovery Facility
SH State Highway
SWRO Seawater Reverse Osmosis
TBM Tunnel Boring Machine
TG Puketoka Formation Tauranga Group
UF Ultrafiltration
WTP Water Treatment Plant
WWTP Wastewater Treatment Plant
Waikato River Water Take and Discharge Proposal – Board of Inquiry | vi
| Executive Summary |
Executive Summary
This study was carried out as part of an options assessment to understand alternative water resources
that could be available to meet the future demand for Auckland’s drinking water supply. Based on the
options assessment review process, purified recycled water for either direct or indirect use were
considered.
The purpose of this report is to present a high-level concept design of three purified recycled water
schemes, including capital and operating cost estimates1. This is to enable a ‘like for like’ comparison
with other similar schemes, such as a desalination scheme located at Rosedale Wastewater
Treatment Plant, and a new water treatment plant to treat water abstracted from the Waikato River.
The estimates are for the purposes of option assessment only, and further work would be required
before establishing project budgets.
Purified recycled water can either be used by directly putting treated drinking water from the AWTP
into the water supply transmission network (commonly referred to as direct potable reuse), or indirectly
by putting the treated drinking water from an AWTP into a raw water source (e.g. storage lake) from
where it is taken and subsequently treated by a second water treatment plant and then into the
transmission network (indirect potable reuse).
This report summarises the concept design of the following three schemes for an Advanced Water
Treatment Plant (AWTP) process at either Rosedale Wastewater Treatment Plant (WWTP) or
Mangere Resource Recycling Facility (RRF), and transmission of treated water to connect into the
wider Auckland transmission system. These are summarised below.
• S2: Indirect potable - Campbell Rd Storage Lake (no surface abstraction): Purified recycled
water from the Rosedale WWTP would be stored in an off-line storage lake at Campbell Road and
then treated to potable standard before being put into supply at Schnapper Rock (a form of
indirect potable re-use as shown in Figure ES-1).
Figure ES-1: Proposed Scheme for indirect potable purified recycled water Rosedale AWTP to Campbell Rd
Storage Lake (no surface abstraction) – Block Diagram
1
Costs have been scaled from global examples of advanced water treatment plants
Waikato River Water Take and Discharge Proposal – Board of Inquiry | vii
| Executive Summary |
• O2: Direct potable - Rosedale: Purified recycled water from the Rosedale WWTP would be
pumped directly into the bulk supply network at new reservoirs at Schnapper Rock (a form of
direct potable re-use as shown in Figure ES-2.
Figure ES-2: Proposed Scheme for direct potable purified recycled water at Rosedale – Block Diagram
• O2: Direct potable - Mangere: Purified recycled water from the Mangere WWTP would be
pumped directly into the bulk supply network via the Hūnua 4 watermain (a form of direct potable
re-use as shown in Figure ES-3).
Figure ES-3: Proposed Scheme for direct potable purified recycled water at Mangere– Block Diagram
Table ES-1 shows the expected net product flows from an AWTP at Rosedale and Mangere, based on
expected effluent flow.
For the purposes of this report and comparison with other schemes, the infrastructure capacity and
investment for recycled water schemes are split into two stages:
• 75MLD: New treatment facility with a maximum sustainable daily average capacity of 75MLD
(average across 12 months).; followed by
• Upgrade to 150MLD: Addition of another maximum sustainable daily average capacity of 75MLD,
totalling 150MLD (average across 12 months).
Waikato River Water Take and Discharge Proposal – Board of Inquiry | viii
| Executive Summary |
The Mangere RRF can achieve both the first stage of 75MLD and second stage of 150MLD based on
the dry weather effluent flow conditions for 2020.
The Rosedale WWTP can achieve the first stage in 2038 based on the average effluent flow
conditions but not during dry weather flow periods 2. The Rosedale WWTP would not be able to
achieve the 150MLD until after 2038 based on average effluent flow. The 150MLD scheme would
need to either be delayed until sufficient flow is available at the Rosedale WWTP or a smaller scheme
could be installed at Rosedale to match the North Shore effluent flows. Further analysis would be
required to evaluate the impact of the dry weather flows for the Rosedale WWTP option.
Table ES-1: AWTP plant capacity
Description Rosedale 2038 Rosedale 2058 Mangere 2020
WWTP Effluent
Dry weather flow (MLD) 86 104 259
Average flow (MLD) 144 174 330
Peak flow (MLD) 433 520 875
AWTP
Influent (gross) Av. Daily Flow 144 174 192
(MLD)(1)
Reject Flows (20% of influent) 17 (dry weather) 21 (dry weather) 39
(MLD) 29 (average) 35 (average)
Dry Weather Net Product Flows 69 83 150
(MLD)
Average Net Product Flows (MLD) 115 139
(1) As Mangere RRF has sufficient effluent flow to achieve the 150MLD AWTP capacity with the dry weather flow, the influent
flow is what is required to achieve 150MLD net product flow. For Rosedale WWTP, the influent flow is equal to average
effluent flow.
The CAPEX cost estimate summary for the recycled water schemes is summarised in Table ES- 2
and is considered to have an accuracy of -25% to +50% at this level of design development. These
high level estimates are an indication of cost only for comparison to other options and should not be
used for budgeting purposes.
Table ES- 2: CAPEX cost estimate for 75MLD and 150MLD Facilities. Values in NZD millions ($,000,000)
Option Stage AWTP Reservoir Transmission(1) Indirect Total Total scheme
and WTP Costs
S2: Indirect 75MLD $415 $335 $360 (2) $462 $1,600 $1,900
potable - 150MLD $180 $70 $0 $105 $350
Campbell Rd
Storage Lake
Option 3 (no
surface
abstraction)
2
Dry weather is defined as a consecutive period of seven days or longer with total rainfall lass than or
equal to 1mm
Waikato River Water Take and Discharge Proposal – Board of Inquiry | ix| Executive Summary |
Option Stage AWTP Reservoir Transmission(1) Indirect Total Total scheme
and WTP Costs
O2: Direct 75MLD $415 n/a $65 $200 $680 $940
potable - 150MLD $180 n/a $0 $76 $260
Rosedale
pumped
O2: Direct 75MLD $380 n/a $50 $180 $610 $840
potable - 150MLD $150 n/a $0 $63 $210
Mangere
pumped
(1) Includes treated water storage and pipelines
(2) Includes pipeline from AWTP to Campbell Road Storage Lake
(3) Rounded to the nearest 2 significant figures
(4) An AWTP at Rosedale WWTP is assumed to be more expensive than one at Mangere RRF as Rosedale WWTP has less
treatment at the existing WWTP than at Mangere RRF, so an additional treatment process is assumed to be needed at the
Rosedale AWTP.
The OPEX cost estimate summary is summarised in Table ES- 3. These are based on examples of
reported operation costs from existing AWTPs ranging from 0.3 – 0.6 NZD/m3 and are suitable for
option comparison purposes only. An estimate of 0.24NZD/m3 has been used for the Campbell Road
WTP, based on the Waikato A WTP operating cost estimates.
Table ES- 3: OPEX Cost Estimate ($/annum)
Operating Cost ($/yr)
75MLD 150MLD
S2 – Indirect potable - Campbell Rd Storage Lake $15 million to $29 million
Option 3 (no surface abstraction) $23 million $45 million
O2: Direct potable - Rosedale pumped $8 million to $16 million to
$16 million $33 million
O2: Direct potable - Mangere pumped $8 million to $16 million to
$16 million $33 million
While purified recycled water (direct and indirect) are technically feasible, they are unlikely to be
achievable in the short term in New Zealand. This is because a change to the existing regulatory
framework for drinking water in New Zealand would be required to enable direct or indirect potable
purified recycled water use. There is currently no certainty about the willingness of central
government to progress such a change, and the timeframe in which this could be achieved,
particularly given the likelihood of community resistance and cultural concerns in relation to purified
recycled water as a drinking water source. As an example, Perth’s scheme outreach programme ran
for approximately 10 years (which included political support) before agreement to implement a purified
recycled water scheme was reached.
Based on overseas experience, community resistance would seem particularly likely if purified
recycled water was pumped directly into the treated water network as with option O2, and is also likely
to be significant with option S2. A direct scheme (O2) is likely to require more time to gain community
acceptance, particularly as the size of the schemes proposed in this report (up to 150MLD purified
Waikato River Water Take and Discharge Proposal – Board of Inquiry | x| Executive Summary |
recycled water) are larger than direct purified recycled water plants that are currently operational,
which range from 2 – 27MLD.
The lead time is therefore expected to be considerable as Watercare would need to develop pilot
plants, influence changes to legislation and develop a community engagement programme. Therefore,
it is not expected that a full-scale recycled water scheme could be implemented (constructed and
commissioned) within the next 15 years. It could take 15 years just to get community acceptance and
a regulatory framework in place, then potentially a further 5 – 10 years to implement a full-scale plant.
This report concludes with a number of assumptions and risks that need to be addressed if any of the
options in the report are carried forward.
Waikato River Water Take and Discharge Proposal – Board of Inquiry | xi| Introduction |
1 Introduction
1.1 Introduction
Watercare Services Limited (“Watercare”) is a lifeline utility providing water and wastewater services
to a population of 1.7 million people in Auckland. Its services are vital for life, keep people safe and
help communities to flourish. More specifically, Watercare is the council-controlled organisation of
Auckland Council responsible for municipal water supply within Auckland, and the provider of bulk
water supply services to Pokeno and Tuakau in the Waikato District 3.
Watercare supplies approximately 440,000 cubic metres of water per day (“m3/day”) on average
across the year, derived from a range of sources and treated to the Ministry of Health Drinking Water
Standards for New Zealand 2005 (revised 2018).
Watercare’s three main water supply sources are:4
• Water dams in the Hūnua and Waitākere ranges;
• A groundwater aquifer in Onehunga; and
• The Waikato River.
The exact proportion supplied from each source varies daily, depending on a range of factors
including the levels in the dams, forecast rainfall, treatment plant capacity, and maintenance
requirements.
In December 2013, Watercare applied to the Waikato Regional Council (“WRC”) for resource consents
to authorise abstracting an additional 200,000 m3/day (net) of water from the Waikato River, a new
water intake structure and discharges from a new water treatment plant. Since that time, Watercare’s
water take application (and the associated applications) have been on hold while the WRC processes
and determines other applications to take water from the Waikato River Catchment that were lodged
before Watercare’s application.
During the period from late 2019 through to mid-2020, the Auckland region experienced one of the
most extreme drought events in modern times with rainfall for the period between January and May
2020 being approximately 30% of what would normally be expected for that period. At Watercare’s
recommendation, in May 2020 Auckland Council imposed water use restrictions in Auckland for the
first time since the early 1990s. Watercare also took additional steps to improve security of supply
during the drought by exercising emergency powers under section 330 of the Resource Management
Act 1991 (RMA),5 and by re-establishing supply from previously decommissioned sources. 6
While the above steps have been taken to ensure Auckland’s short-term water supply requirements
are met, the focus has now turned to the future. Watercare focus remains planning for water demand
over the long term by securing sustainably sourced water to achieve:
3
Under a bulk supply agreement with Waikato District.
4
Watercare also operates individual water supplies from various sources including groundwater and
surface water for several other communities such as Muriwai, Algies Bay, Snells Beach, Bombay,
Waiuku, Warkworth, Helensville and Wellsford.
5
Reduced environmental flows from the Waitakere, Wairoa and Cosseys dams, and a short term
take from the Waikato River.
6
Groundwater bores at Pukekohe and the Hays Creek dam in Papakura.
Waikato River Water Take and Discharge Proposal – Board of Inquiry | 1| Introduction |
• Certainty of supply in up to a 1:100-year drought with 15% residual dam storage; and
• Certainty of supply to meet the peak demand.
On 30 June 2020, after considering advice provided by the Environmental Protection Authority, the
Minister for Environment issued a direction under section 142(2) of the RMA to call in Watercare’s
2013 application and refer the matter to a Board of Inquiry to determine the application. The Minister
direction recognised Watercare’s application as a proposal of national significance.
Given the passage of time since the 2013 application was lodged, Watercare has updated the
application to address a range of matters including updates to population and demand assessments,
changes to the policy framework within which the application is to be considered, consultation that has
taken place, reassessment of potential water supply sources and intake options, and updated
assessments of environmental effects including the effect that granting Watercare’s application would
have on the allocation available to other users. The updated application will be heard by the Board of
Inquiry.
The most significant revision to the 2013 application, resulting directly from Watercare’s ongoing
engagement with Waikato-Tainui is a reduction in the volume of the proposed water take from 200,000
m3/day (net) to 150,000 m3/day (net). This reduction reflects Waikato-Tainui’s special relationship with
the Waikato River as outlined in the Waikato-Tainui Raupatu Claims (Waikato River) Settlement Act
2010. It recognises Waikato-Tainui’s relationship with the Waikato River and its respect for the River
lies at the heart of Waikato-Tainui’s spiritual and physical wellbeing, tribal identity and culture.
Watercare currently holds three resource consents authorising the abstraction of water from the
Waikato River adjacent to the Waikato Water Treatment Plant (“Waikato WTP”) near Tuakau as
follows:
a) Resource consent 960089.01.04 authorising a net take rate of up to 150,000 m 3/day at any time
of the year.
b) Resource consent 141825.01.01 (referred to as the “Seasonal Water Take” consent)
authorising a net take rate of up to:
i) 100,000 m3/day during the period 1 May to 30 September (inclusive); and
ii) 100,000 m3/day during the period 1 October to 30 April (inclusive) when the 7-day rolling
average flow of the Waikato River at Rangiriri exceeds 330.03 m3/second.
c) Resource consent 142090.01.01 (referred to as the “Hamilton City Council Water Allocation”
consent), authorising a net take rate of up to 25,000 m 3/day (or such lesser volume as
determined by Hamilton City Council as being available for any given day) during the period 1
October to 30 April (inclusive). This is a short-term consent till 1 May 2023.
In the event that the consent sought through the Board of Inquiry process is granted for the volume
sought, Watercare proposes that its Seasonal Water Take Consent and Hamilton City Council Water
Allocation consent would be surrendered. Watercare’s combined take from the Waikato River under
its existing resource consent 960089.01.04, and the new water take consent sought through the Board
of Inquiry would not exceed a year round net take volume of 300,000 m3/day.
This report provides an assessment of three purified recycled water schemes, prepared to support the
application to be considered by the Board of Inquiry.
1.2 Background
Watercare Services Ltd (Watercare) appointed Beca Ltd (Beca) to prepare an assessment of the
potential water resource options for Auckland and to identify one or more options that would enable
Waikato River Water Take and Discharge Proposal – Board of Inquiry | 2| Introduction |
Watercare to meet demand on its drinking water supply. This assessment is part of Watercare’s
analysis of alternatives to an additional surface water take from the Waikato River, which was the
subject of a resource consent application lodged with the Waikato Regional Council in 2013 and is
now to be determined by a Board of Inquiry in 2021.
This report specifically looks at the option of purified recycled water as a strategic water source for
Auckland. Purified recycled water can either be used by directly putting treated drinking water into the
water supply (commonly referred to as direct potable reuse), or indirectly by putting the treated
drinking water into a raw water source (e.g. storage lake) from where it is taken and subsequently
treated by a second water treatment plant (indirect potable reuse).
Several purified recycled water options have been considered in the past (in particular in CH2M
Beca’s 2015 report “Cost Estimate for a Desalination Plant and Wastewater Reuse Scheme”) and
several options were reviewed in October 2020 (reference numbers are from Beca’s “Water Source
Options Alternative Assessment for the Metropolitan Supply” 2020 report):
• S3: Indirect potable - Campbell Rd Storage Lake Option 4 (purified recycled water & surface
abstraction): Surface abstraction from the Ararimu Stream, Rangitopuni Stream, and
Kaukapakapa River, supplemented by purified recycled water from the Rosedale Wastewater
Treatment Plant (WWTP), stored in an off-line reservoir at Campbell Road (indirect potable re-
use).
• S2: Indirect potable - Campbell Rd Storage Lake Option 3 (no surface abstraction): Purified
recycled water from the Rosedale WWTP would be stored in an off-line reservoir at Campbell
Road and then treated to a potable standard before being put into supply (indirect potable re-use).
• O3: Indirect potable - Mangere source augmentation or substitution (generic location): purified
recycled water from the Mangere WWTP would be stored in the Lower Huia and Lower Nihotupu
dams then treated at a new water treatment plant at Huia (indirect potable re-use).
• O2: Direct potable - Rosedale or Mangere pumped: Purified recycled water from the Rosedale or
Mangere WWTP would be pumped directly into the bulk supply network
• O24: Indirect potable - Mangere and Wairoa to Rautawhiti Dam (purified recycled water & surface
abstraction): Surface abstraction from the Wairoa River, supplemented by purified recycled water
from the Mangere WWTP, stored in an off-line reservoir, the Rautawhiti Dam.
• O22: Direct potable - Pukekohe pumped or tankered: Purified recycled water from the Pukekohe
WWTP would be pumped directly into the bulk supply network or made available by tanker
• O5, O5, O6 and O23: Recycled water for non-drinking purposes
Three options were selected to be developed further (refer to Beca’s “Water Source Options
Alternative Assessment for the Metropolitan Supply” 2020 report for the shortlisting process):
• S2: Indirect potable - Campbell Rd Storage Lake Option 3 (no surface abstraction)
• O2: Direct potable - Rosedale pumped
• O2: Direct potable - Mangere pumped
This report allows Watercare to understand the costs, benefits and potential impacts for a
representative purified recycled water scheme. These options have therefore been developed for the
purpose of enabling different types of water resource options to be compared with each other.,.
Waikato River Water Take and Discharge Proposal – Board of Inquiry | 3| Introduction |
1.3 Purpose of this report
The purpose of this report is to:
• Review the regulatory framework required to implement a purified recycled water facility in
Auckland; and
• Present a high-level concept design of three purified recycled water schemes, including capital
and operating cost estimates, enabling a ‘like for like’ comparison with other water resource
options.
The location of the treatment plant, transmission and storage into the network has a bearing on the
cost of the scheme, and therefore ‘location specific’ factors like Power, Consenting and Geotechnical
are important to the feasibility and cost of the identified solution, and therefore key to the comparison
of options.
This report forms an input to the wider options selection process. The general approach to this
process is summarised as Figure 1-1. This shows a number of different technical reports being used
to support the wider options assessment process. This recycled water report is one of these inputs.
The options assessment process considers the positive and negative aspects of these potential water
resources schemes to enable a preferred option to be recommended.
Figure 1-1: How this Purified Recycled Water Scheme Concept Report feeds into the overall options assessment
process in the “Water Source Options Alternative Assessment for the Metropolitan Supply” report
Waikato River Water Take and Discharge Proposal – Board of Inquiry | 4| Regulatory Framework |
2 Regulatory Framework
2.1 New Zealand Context
There is no New Zealand regulation or guidance on purified recycled water for potable (drinking water)
use. A change to the existing regulatory framework for drinking water in New Zealand (DWSNZ)
including in particular an update to the Drinking-Water Standards for New Zealand 2005 (Revised
2018), would be required to enable direct or indirect purified recycled water use.
While purified recycled water (direct and indirect) are technically feasible, they are unlikely to be
achievable in the short term. This is because a change to the existing regulatory framework for
drinking water in New Zealand would be required to enable direct or indirect purified recycled water
use. There is currently no certainty about the willingness of central government to progress such a
change, and the timeframe in which this could be achieved, particularly given the likelihood of
community resistance and cultural concerns in relation to purified recycled water as a drinking water
source. As an example, Perth’s scheme outreach programme ran for approximately 10 years (which
included political support) before agreement to implement a purified recycled water scheme was
reached.
In the absence of any New Zealand regulation or guidance documentation, Watercare would need to
work with Taumata Arowai to establish acceptable regulation and guidelines for New Zealand. This is
likely to be based on the Australian Guidelines for Water Recycling: Augmentation of Drinking Water
Supplies (AGWR 2008)7, and/or the World Health Organisation’s 2017 Potable Reuse: Guidance for
Producing Safe Drinking Water, and would include developing a framework and standards for potable
purified recycled water use in New Zealand.
Under the Water Services Bill, which has not yet been enacted (expected in the second half of
2021), Taumata Arowai must review the DWSNZ within 5 years after the commencement of the
Water Services Act. A framework for purified recycled water could be developed as part of this
review of the DWSNZ. Following this review, if the responsible Minister decides the DWSNZ need
to be updated, Taumata Arowai will undertake a public consultation process, which includes the
opportunity to make submissions. After that, an Order in Council made on the recommendation of
the Minister is required in order to amend or update the DWSNZ.
As community opposition is highly likely, particularly for a direct scheme, it is expected that the lead
time would be considerable. Watercare would need to develop pilot plants, influence changes to
legislation and develop a community engagement programme. Therefore, it is not expected that a full-
scale recycled water scheme could be implemented (constructed and commissioned) within the next
15 years. It could take 15 years just to get community acceptance and a regulatory framework in
place, then potentially a further 5 – 10 years to implement a full-scale plant.
2.2 Global Application
The number of purified recycled water applications is increasing around the world with operational
facilities currently in the US, Australia, South Africa, Namibia, Singapore and Belgium, ranging in
capacity from 2 – 490MLD. This increase in application has resulted in regulators in many countries
7
Australian Guidelines for Recycling (AGWR): Managing Health and Environmental Risks (Phase 2)
(2008); Augmentation of Drinking Water Supplies. Environment Protection and Heritage Council,
National Health and Medical Research Council & Natural Resource Management Ministerial Council
ISBN 1 921173 20 3 (Print copy), ISBN 1 921173 19 X (Web copy), May.
Waikato River Water Take and Discharge Proposal – Board of Inquiry | 5| Regulatory Framework |
investigating standards and monitoring requirements for such schemes – the most recent being the
World Health Organisation’s publication in October 2017; “Potable Reuse – Guidance for Producing
Safe Drinking Water”8.
Potable purified recycled water schemes generally take one of four forms, as shown in Figure 2-1.
Common to all four is the wastewater treatment plant (WWTP) and the Advanced Water Treatment
Plant (AWTP). The differences are in how the AWTP product water is handled.
This section of this report addresses the technologies commonly applied in the AWTPs, noting that
there will be multiple process units in line with the ‘multiple barrier’ requirement outlined in the 2008
AGWR7 document.
Figure 2-1: Purified Recycled Water Scenarios
8
World Health Organisation (2017). Potable Reuse: Guidance for Producing Safe Drinking Water.
ISBN 978-92-4-151277-0, July.
Waikato River Water Take and Discharge Proposal – Board of Inquiry | 6| Regulatory Framework |
The AWTP treatment trains adopted for purified recycled water applications can be grouped into
‘membrane-based’ (incorporating Reverse Osmosis (RO) and ‘non-membrane based’ (incorporating
ozone and activated carbon), with or without a form of environmental buffer (e.g. surface reservoir or
groundwater aquifer).
Figure 2-2 summarises examples of international potable recycled water schemes currently in
operation (WHO 2017)8 and highlights the technologies adopted in each of the AWTPs in question.
Figure 2-2: Examples of AWTP Treatment Trains. Note all product streams are chlorinated.
The efficient removal of dissolved solids, dissolved organic carbon, pathogens and trace organics by
RO has resulted in more than half of all purified recycled water AWTPs worldwide, and 80% of those
in California, adopting this process unit in their treatment trains (Horstmeyer, N et al, 2017) 9. It is still
the most widely implemented process around the world.
However, RO does come with two disadvantages: high energy use and the production of a brine or
concentrate flow that can account for 15-20% of the inflow to the unit.
Brine disposal in coastal areas is generally not a problem as it can be discharged to the ocean. For
inland communities, disposal of the brine may be an issue if there is not enough wastewater flow to
blend the brine with and dispose of it. It is mainly for this reason that inland communities have been
considering the Ozone-BAC-based treatment trains that incorporate ozonation, activated carbon
filtration, low pressure membrane filtration and either the UV/AOP process or natural treatment
processes such as wetlands, riverbank filtration, aquifer recharge or soil aquifer treatment (SAT).
9
Horstmeyer, N., Weibach, M., Koch, K. and Drewes, J.E. (2017). A novel concept to integrate energy
recovery into potable water reuse treatment schemes. Journal Water Reuse & Desalination.
Waikato River Water Take and Discharge Proposal – Board of Inquiry | 7| Regulatory Framework |
The Rosedale WWTP currently discharges to the Rangitoto Channel via a 2.3km pipeline to Mairangi
Bay and a 2.1km long ocean outfall. The brine could potentially be discharged through the existing
ocean outfall, by blending with the treated wastewater. It is noted that any brine discharge would need
to comply with the future wastewater discharge limits.
The most significant quality difference between the RO-based and Ozone-BAC- based AWTP
treatment trains will be that of total dissolved solids (TDS). However, the impact of the higher TDS is
generally mitigated by blending the product water with other water supplies in reservoirs, aquifers and
the distribution systems or by side-stream RO treatment if the blending is not adequate. Further
comment on the Ozone-BAC- based AWTP performance can be found in the paper entitled
“Performance and Validation of Non-RO Treatment Trains for Potable Reuse” that was presented at
the IWA Asia Pacific Water Recycling Conference in Brisbane by Law et al in July 2013 10 and which
covered details of work carried out in South Africa, Australia and Namibia.
There is currently a clear majority throughout the world favouring indirect with the direct option slowly
gaining in the US (California and Texas mainly) as costs and sustainability considerations come to the
fore. The direct plants in operation currently have capacities of 2-27MLD, while operating indirect
schemes are up to 490MLD.
Further reading and references can be found in Appendix A.
2.3 Validated Pathogen Log Removal Values (LRVs)
A log removal value (LRV) is a measure of the ability of a treatment processes to remove pathogenic
microorganisms.
Table 2-1 identifies the minimum log reductions for producing drinking water from sewage defined in
the AGWR (2008)7, WHO (2017)8 and in California and Texas.
Validated LRVs for the individual process units that make up a RO-based and Ozone-BAC based are
also summarised in Table 2-1. The sum of the LRVs for each pathogen exceeds the LRV
requirements of the Australian and WHO requirements.
Table 2-1: Validated Pathogen LRVs
Process Barriers Bacteria Viruses Protozoa
Campylobacter Norovirus Cryptosporidium
Guidelines:
AGWR (2008) 8.1 9.5 8 (Crypto)
WHO (2017) 8.5 9.5 8.5 (Crypto)
California ns 12 10 & 10
Texas ns 8 5.5 & 6
Note: AGWR, WHO & California LRVs are from Raw Sewage, while Texas values are
from WWTP effluent to product water
RO-based:
WWTP 1 0.5 0.5
10
Law, I., Menge, J., Reungoat, J. and Mieog, J. (2013). Performance and Validation of Non-RO based
Treatment Trains for Potable Reuse. Paper presented at Asia Pacific Water Recycling Conference
2013, Brisbane, Australia, 1-4 July.
Waikato River Water Take and Discharge Proposal – Board of Inquiry | 8| Regulatory Framework |
Process Barriers Bacteria Viruses Protozoa
Campylobacter Norovirus Cryptosporidium
Chemical Clarification & 1.5 1 1.5
Filters
UF 4 0 4
RO 2 2 2
UV/AOP 4 4 4
Chlorination 3 3 0
TOTAL LRV 15.5 10.5 12
Ozone-BAC-based:
WWTP 1 0.5 0.5
Chemical Clarification & 1.5 1 1.5
Filters
Ozone 2 2 0.5
BAC 0 0 0
GAC11 0 0 0
UF 4 0 4
UV/AOP 4 4 4
Chlorination 3 3 0
TOTAL LRV 15.5 10.5 10.5
2.4 Observations and Conclusions
There is now clear evidence from around the world that a safe and wholesome water can be
recovered from municipal wastewaters through the application of a ‘multiple barrier’ approach (AGWR
(2008)7, WRF (2015)12 and WHO (2017)8); starting with the trade waste control program and then
moving through the WWTP, which should preferably be operated to achieve high levels of nitrogen
removal, to the AWTP which can be either RO-based or Ozone-BAC- based.
As part of a trade waste control program, the trade waste regulations are likely to need a review to
include more stringent assessment of hazards, risk assessments, operational monitoring and controls
and incident management.
While the RO-based treatment train is most commonly used, there is increasing interest in the Ozone-
BAC-based trains because of lower energy consumption and less brine disposal issues.
At this stage of preliminary evaluation, the most commonly used RO based treatment train is
assumed, because it represents a conservative position at this early stage for comparison against
other options. Other non-RO based alternatives should be evaluated during next phase of
While GAC can achieve some log removal of pathogens, typically no credit is taken since the GAC is
11
designed for removal of organics and not particulates in this application.
12
Water Reuse, American Water Works Association, Water Environment Association, National Water
Research Institute. (2015). Framework for Direct Potable Reuse. Water Reuse Project Number: 14-20,
ISBN: 978-1-941242-30-8.
Waikato River Water Take and Discharge Proposal – Board of Inquiry | 9| Regulatory Framework |
development if a purified recycled water scheme is identified as a potential water resource for
Auckland.
Waikato River Water Take and Discharge Proposal – Board of Inquiry | 10| Indirect Potable – Campbell Road Storage Lake Option 3 |
3 Indirect Potable – Campbell Road Storage Lake Option 3
(No Surface Abstraction) Scheme
3.1 Scheme Overview
The treatment process for this scheme would be to treat effluent from the Rosedale WWTP. Purified
recycled water from the Rosedale WWTP would be stored in an off-line storage lake at Campbell
Road and then treated to potable standard before being put into supply at Schnapper Rock.
The indirect potable purified recycled water scheme is based on the schemes in Australia in
accordance with AGWR 2008. According to these regulations, the outlet from the AWTP plants is
required to be to drinking water quality, even if the water is subsequently stored in a lake and then
treated further.
The proposed indirect potable purified recycled water scheme is as follows:
• Effluent from Rosedale WWTP is treated by an advanced water treatment plant (AWTP) on the
Rosedale site;
• The purified recycled water from the outlet of the AWTP is suitable for drinking;
• A 25ML reservoir and pump station located at the AWTP site
• The purified recycled water is pumped to a new 27million m3 storage lake at Campbell Road; and
• A new 150MLD water treatment plant at Campbell Road treats the reservoir water and is pumped
to new treated water reservoir at Schnapper Rock.
Figure 3-1 shows the indirect potable purified recycled water scheme in block diagram form.
Figure 3-2 shows schematically how this could be achieved at Rosedale WWTP and Campbell Road.
Figure 3-1: Proposed Scheme for Rosedale AWTP to Campbell Rd Storage Lake – Block Diagram
Waikato River Water Take and Discharge Proposal – Board of Inquiry | 11| Indirect Potable – Campbell Road Storage Lake Option 3 |
Figure 3-2: Proposed Scheme for Rosedale AWTP to Campbell Rd Storage Lake – Aerial
The infrastructure capacity and investment for recycled water scheme are split into two stages:
• 75MLD: New treatment facility with a maximum sustainable daily average capacity of 75MLD
(average across 12 months). This stage includes the Campbell Road Storage Lake, power supply
and transmission pipework for a 150MLD plant and an AWTP and WTP with the 75MLD capacity.;
followed by
• Upgrade to 150MLD: Addition of another maximum sustainable daily average capacity of 75MLD,
totalling 150MLD (average across 12 months).
3.2 Rosedale AWTP Process Design Basis
3.2.1 WWTP process
The Rosedale wastewater treatment plant (WWTP) is 12 km north of the Auckland CBD and based at
the intersection of State Highway 1 and the Upper Harbour Highway (SH18) in the North Shore of the
Auckland region.
The Rosedale WWTP liquid stream process consists of:
• Primary sedimentation;
• Secondary biological treatment (MLE) and clarification;
• Peak flow treatment (chemically assisted sedimentation – CAS);
• Tertiary pond; and
• UV disinfection.
The effluent from the Rosedale WWTP currently discharges to the Rangitoto Channel via a 2.3km
pipeline to Mairangi Bay and a 2.1km long ocean outfall. The outfall is designed for 6m³/s which is the
WWTP predicted peak capacity in 2058. Appendix C contains the Rosedale WWTP population and
flow forecast from 2018 – 2063.
Waikato River Water Take and Discharge Proposal – Board of Inquiry | 12| Indirect Potable – Campbell Road Storage Lake Option 3 |
Table 3-1 shows the expected capacity of an AWTP at Rosedale, based on the expected effluent flow.
For the purposes of this report, the net production capacity of the proposed AWTP is 150MLD, for
comparison with the Mangere recycled water option, desalination at Rosedale option and the
proposed Waikato A WTP.
The Rosedale WWTP can achieve the first stage in 2038 based on the average effluent flow
conditions but not during dry weather flow periods. Rosedale would not be able to achieve the desired
150MLD capacity until after 2058 based on average effluent flow; at 2058 it is expected that the
average AWTP net product flow would be 139MLD. The 150MLD scheme would need to either be
delayed until sufficient flow is available at the WWTP or a smaller scheme could be installed at
Rosedale to match the North Shore effluent flows.
Further analysis would be required to evaluate the impact of the dry weather flows for the Rosedale
WWTP option. The capacity of the potential yield at the Rosedale site is further discussed in the
report “Water Source Options Alternative Assessment for the Metropolitan Supply – Waikato River
Water Take Application”.
Table 3-1: Rosedale AWTP Capacity
Description 2038 2058 Future
Rosedale WWTP Effluent
Dry weather flow (MLD) 86 104
Average flow (MLD) 144 174
Peak flow (MLD) 433 520
Rosedale AWTP
Influent (gross) Av. Daily Flow 144 174 192
(MLD)
Reject Flows (20% of influent) 17 (dry weather) 21 (dry weather) 39
(MLD) 29 (average) 35 (average)
Dry Weather Net Product Flows 69 83
(MLD)
Average Net Product Flows (MLD) 115 139 150
3.2.2 Advanced Water Treatment Plant Process
While section 2 of this report notes that there is increasing interest in the Ozone-BAC-based trains
because of lower energy consumption and brine disposal issues, at this stage of preliminary
evaluation, the most commonly used RO based treatment train is assumed. This is shown as Figure
3-3 and is used because it represents a conservative position at this early stage for comparison
against other options.
Waikato River Water Take and Discharge Proposal – Board of Inquiry | 13| Indirect Potable – Campbell Road Storage Lake Option 3 |
Figure 3-3: Typical RO based process flow diagram for an AWTP
Waikato River Water Take and Discharge Proposal – Board of Inquiry | 14| Indirect Potable – Campbell Road Storage Lake Option 3 |
3.2.3 Filtered WWTP Effluent quality
The PFD in Figure 3-3 requires a minimum treatment level to be supplied from the existing
Wastewater Treatment Plant.
The typical required feed effluent (i.e. feed stream into the AWTP) parameters and how they compare
to current effluent from Rosedale WWTP and Mangere Resource Recovery Facility (RRF) are shown
in Table 3-2 Effluent quality figures, including any expected future trade waste, should be confirmed by
Watercare.
Table 3-2: Feed effluent parameters
Parameters Typically required Mangere RRF effluent Rosedale WWTP effluent
(2)
TOC 8-11mg/L Unknown / TBC Unknown / TBC
BOD| Indirect Potable – Campbell Road Storage Lake Option 3 |
3.2.4 Strainer upstream of ultra-filtration (UF)
The UF feed pumps will feed a set of automatic strainers operated in parallel. Automatic strainers
protect the UF membranes from particles in the 100-300 micron size range. These strainers
automatically backwash when the headloss threshold or backwash timer duration is met. The
backwash procedure usually lasts less than a minute and only a small amount of waste is generated.
3.2.5 UF
UF is a preferred pre-treatment system for AWTP processes that include RO as it provides high
quality water consistently to the downstream RO process. It also provides verifiable means of
achieving log-removal of pathogens through use of integrity testing. UF systems do however require
periodic chemical cleaning.
These include frequent maintenance wash cleans several times a week, and more rigorous clean-in-
place every 30 days or so. They also require use of strainers upstream, membrane replacement every
7 to 10 years and have the potential for fibre breaks. However, given the high quality water UF
provides and the log- removal of pathogens it achieves, UF is standard in AWTP facilities. Downtime
for cleaning and maintenance is factored into the design such that the scheme is able to achieve the
required net production capacity.
3.2.6 Cartridge Filters
The cartridge filters provide a safety barrier upstream of the RO membranes for any particles or debris
that may have accumulated in the MF/UF-RO buffer tank.
3.2.7 Three (3) stage Reverse Osmosis
The effluent from the RO cartridge filters feeds the RO trains where the high-pressure RO pumps
increase the water pressure and the water enters the RO vessels. The RO vessels contain several
elements that contain the spiral wound, semi-permeable RO membranes. The RO membranes
selectively allow water through the membranes while rejecting dissolved organic and inorganic
contaminants, bacteria, and viruses. The purified water that passes through the RO membranes is
collected as permeate and flows to the UV-AOP system. The remaining water containing the rejected
contaminants, referred to as concentrate, is directed to the brine collection wet-well.
To achieve a recovery of 85%, a three stage system is required. An interstage booster pump coupled
with an energy recovery device is provided to pressurise the feed water to the second stage to help
balance the fluxes between the first and second stage. In addition to balancing the fluxes, which
minimizes higher rate of fouling of 1st stage, it also helps reduce overall energy consumption of the
RO system.
The ancillary systems for the RO system include a flush system and a clean-in-place system. The
flush system consists of a permeate tank and a pump. Whenever the RO train goes down, it is flushed
with permeate. The cleaning system is used to clean the membranes in-situ periodically as they foul.
The system consists of a chemical makeup tanks, neutralisation tank, cartridge filter and pumps.
3.2.8 UV AOP
Ultraviolet (UV) advanced oxidation processes (AOPs) provide treatment via three different pathways:
(1) Microbial disinfection via direct photolysis ( i.e., Giardia, Cryptosporidium and virus); (2) Chemical
contaminant destruction via direct photolysis ( i.e., NDMA); and (3) Chemical contaminant destruction
via advanced oxidation ( i.e., 1-4-Dioxane).
The UV-AOP system will need to be designed to treat the maximum combined flow from all RO trains,
and the effluent from the UV-AOP system will flow to the decarbonation system.
Waikato River Water Take and Discharge Proposal – Board of Inquiry | 16You can also read
