The Council needs to upgrade Akaroa’s wastewater system, which reflects our commitment to ensure the Akaroa community is provided with a high quality wastewater system.

Akaroa HarbourA new site has been chosen for technical and operational reasons, and recognises the historical importance of the Takapūneke Historic Reserve, where the current plant is located.

The new plant will be a compact modern facility, making use of recent improvements in wastewater treatment and attractively landscaped to limit visual impact. It will be quiet and will not cause odour. This will minimise the new plant’s impact on the environment and the community.

Please email the project team if you have any questions or would like to sign up for our Akaroa wastewater scheme project e-newsletter.

Benefits of the Akaroa wastewater scheme

  • The scheme recognises the historic and cultural importance of Takapūneke Historic Reserve to all New Zealanders and particularly to Ngāi Tahu.
  • The modern plant will produce extremely clean treated wastewater, which could eventually be used as a non-potable water supply (e.g. for watering public parks and flushing toilets).
  • The plant contributes to higher water quality that supports water sports, recreation, tourism and aquaculture in the region.
  • The new site is closer to more potentially suitable land for irrigation.

Latest news

In June 2017, the flow meter at the Akaroa wastewater treatment plant was found to be faulty. The flow data from the flow meter had been used in the design of the Akaroa wastewater scheme and for the reuse and disposal options. New flow meters were installed in July 2017 and the data from these shows that the flow is much higher than previously thought. Due to seasonal variations in visitor numbers, flow data was gathered over summer and new design flows will be determined in June 2018. 

In addition to the areas previously considered for irrigation of treated wastewater to land, two new areas are being considered (Redcliffe Point and Hickory Bay). Deep well injection is also being considered and more work is being done on non-potable reuse. Work to reduce groundwater infiltration and stormwater inflow into the wastewater network is also underway.

A briefing to the Banks Peninsula Community Board on the Akaroa Wastewater Scheme was given on 30 October 2017 [PDF, 327 KB]. The community board decided to reconvene the Akaroa Treated Wastewater Working Party to consider reuse options in light of the new flow data.

The Environment Court has granted an extension to the appeal and a progress report needs to be provided to the court by 1 March 2019. The Council expects to consult on options in late 2018 and hopes to make a decision on which option to pursue in 2019. 

A public meeting was held in the Gaiety Hall in Akaroa on 4 April 2018 to update the community about what has been happening on the project over the previous few months and to introduce a new option of deep bore injection that is being considered. Two presentations were given:

Resource consents

The Council has obtained resource consents for building and operating the new Akaroa Wastewater Treatment Plant on Old Coach Road and a new pump station in the boat park at Childrens Bay, and for upgrading wastewater mains and the three existing pump stations. However, the Council's applications for consents to construct a new pipe outfall to Akaroa Harbour, and discharge treated wastewater via that pipe outfall, were declined, on the grounds that the discharge was offensive to Ngāi Tahu and because the Hearing Commissioners considered that alternatives to the discharge to the harbour had not been adequately investigated.  For more information, view the Decision of the Hearings Commissioners(external link).

The Council has lodged an appeal against the decline of those consents but will not be making a decision on pursuing that appeal until it has reassessed alternatives for the discharge.

Lincoln University trials

Lincoln University conducted a lysimeter trial where treated wastewater from the Duvauchelle wastewater treatment plant was irrigated onto soil cores taken from the golf course at Duvauchelle and the Takamatua Peninsula. 

Lincoln University is also conducting a trial where various native plant species are irrigated using treated wastewater from the Duvauchelle wastewater treatment plant. 

The key findings were that wastewater irrigation enhanced pasture growth and tree growth, that treated wastewater could be applied at a rate of 500–800mm per year and that nitrogen leaching was negligible compared to that from grazed pasture. 

Lincoln University Lysimeter Trials and Native Species Irrigation Trials report [PDF, 1.6 MB]

Consultation on reuse, treatment and disposal options

Consultation on reuse, treatment and disposal options – 3 April 2017 to 8 May 2017

Consultation took place on the options for the beneficial reuse, treatment and disposal of treated wastewater from Akaroa. As the flow data on which the options were based is incorrect, there will not be a Council hearing on these options. The consultation booklet [PDF, 15 MB] summarised the options that were considered:

  1. Irrigation of trees or pasture in Robinsons Bay.
  2. Irrigation of trees or pasture at Pompeys Pillar.
  3. Irrigation of trees or pasture in Takamātua Valley, in combination with another area.
  4. Non-potable re-use in Akaroa, in combination with another option.
  5. Disposal via a new outfall pipeline to the mid-harbour (the original proposal for which consent was sought).

For the detailed information about the options consulted on, please refer to the report Akaroa Wastewater Investigation of Alternative Sites for Land Irrigation (CH2M Beca, March 2017) [PDF, 4.2 MB] and its appendices:

Akaroa treated wastewater reuse options working party

At the meeting on 30 January 2017, the Banks Peninsula Community Board received a Community Strategy Toward an Acceptable Solution to the Disposal of Akaroa Wastewater, prepared and adopted by the community of Robinsons Bay and adopted by Friends of Banks Peninsula.  This included a request that the Council takes a collaborative approach with the community on this project and that public consultation is delayed until April to allow this to occur. 

In response to this, the Board resolved to establish a Working Party to collaborate with the community and engage on community concerns about the Akaroa Treated Wastewater Disposal Project, and to delay any further consultation on the project until April 2017. 

The Community Board prepared terms of reference for the working party [PDF, 32 KB].  The notes from each of the working party's meetings are as follows:

The working party prepared a joint statement [PDF, 2.9 MB] summarising matters the working party members agreed and disagreed on. On 30 October 2017 the Banks Peninsula Community Board resolved to reconvene the working party to consider options in light of the new flow data. The notes from each of the subsequent working party's meetings are as follows:

Akaroa wastewater technical experts group

The Akaroa Wastewater Technical Experts Group consists of experts working for the Council, the Friends of Banks Peninsula and Ngāi Tahu. 

The terms of reference for the Akaroa Wastewater Technical Experts Group [PDF, 27 KB], their first joint statement [PDF, 88 KB], second joint statement [PDF, 197 KB] and third joint statement [PDF, 1.1 MB] are available.

Previous investigations and consultation

The Council has been working with Ōnuku Rūnanga, Wairewa Rūnanga, the Akaroa Taiāpure Management Committee and Te Runanga o Ngāi Tahu (the Ngāi Tahu parties) and the community to explore land-based alternatives to the harbour outfall. 

In 2016 the Council considered six options for disposal of treated wastewater:

  1. Year-round irrigation to trees.
  2. Year-round irrigation to pasture.
  3. Summer-only irrigation, with a wetland or infiltration basin and discharge via a coastal infiltration gallery at other times.
  4. Subsurface flow wetland and discharge via a coastal infiltration gallery.
  5. Infiltration basin and discharge via a coastal infiltration gallery.
  6. Outfall pipeline to the mid-harbour (being the one applied for).

A desktop study was undertaken in May 2016 to identify possible areas for land treatment options. The following criteria were used:

  • not too far from the new wastewater treatment plant on Old Coach Road (a two kilometre radius was used), relatively flat (less than 15 degree slope)
  • at least 25 metres from a residential area or waterway
  • property size of at least 1 hectare
  • not known to have land stability issues.

All of the areas identified as possibly suitable for irrigation were on Takamātua Peninsula or in the Takamātua Valley and are in private ownership. Options for access to the needed land are purchase, lease or license. Several of the options required discharge of remaining wastewater in a diffuse way on the coastline, most likely via a coastal infiltration gallery at the end of the Takamātua Peninsula.

Ngāi Tahu strongly supports the options of year-round irrigation to trees and pasture, as they are consistent with their cultural values. The options involving a diffuse coastal discharge were not supported by Ngāi Tahu, as they do not use natural processes to restore the mauri of the wastewater, and continues discharge of it into the harbour. View the Akaroa Treated Wastewater Disposal Options Consultation Booklet [PDF, 1.2 MB] for a description of each of the options that were considered in 2016, and their advantages and disadvantages.  

For more detailed information on each of the options considered in 2016, please see the Akaroa Wastewater Concept Design Report for Alternatives to Harbour Outfall (CH2M Beca, May 2016 [PDF, 3.8 MB]) and the appendices to the report:

The Council sought public feedback on these options between 26 April and 12 June 2016. View the questions and answers from the consultation meetings, and the submissions and project team responses:

Following the public consultation, the Council commissioned preliminary geotechnical investigations, including test pits and infiltration testing on some of the possible irrigation sites at the end of May 2016, and a cover letter [PDF, 1.7 MB] and two reports were received (see appendices A and  B of the CH2M Beca report below for the reports).  The cover letter highlighted the risk of exacerbating instability where the slopes downhill of the irrigation area are steeper than 15 degrees, and their recommendation was that we avoid irrigating those areas. 

These land investigations found that Takamatua Peninsula and Blocks F and H are not suitable for irrigation of treated wastewater and so the Council is no longer considering these locations.  This meant that there was a risk that insufficient land would be available for irrigation and so the Council decided to consider land that may be suitable for irrigation further afield. The areas that met the revised criteria in the wider area were Takamatua Valley, Robinsons Bay and Pompeys Pillar. 

Options 3 to 5, which included a wetland or infiltration basins and a coastal infiltration gallery on the headland of Takamātua Peninsula, were not supported by the community or the Ngāi Tahu parties, so the Council is not considering these options further until land based options have been more fully investigated.

Consultation meetings November to December 2016

A public meeting was held at the Gaiety Hall on Wednesday 9 November 2016 and a presentation [PDF, 4.9 MB]was given to explain why the Council is exploring alternatives to a harbour outfall for treated wastewater disposal, how these three areas were selected, and to provide the results of land investigations for areas that may be suitable for irrigation of treated wastewater.  View the questions raised at the meeting and the answers from the project team [PDF, 95 KB] [PDF 96KB] and responses to questions tabled at the meeting by the Robinsons Bay community [PDF, 174 KB].

A community consultation workshop was held at the Gaiety Hall on Saturday 3 December 2016.  The community provided responses to four questions; see below for photos of these responses:

The proposed Akaroa wastewater scheme

The proposed scheme in the consent application included:

A map showing the components of the Akaroa wastewater scheme above

Akaroa Wastewater Scheme Map

  • replacing the existing trunk pipelines, upgrading the existing pump stations, and constructing a new terminal pump station to pump flows to the new treatment plant
  • a terminal pump station to be located in the Akaroa boat/trailer park, which will incorporate fine screens and grit removal, to protect the progressive cavity pumps and to provide primary treatment
  • a new biological nitrogen removal (BNR) membrane wastewater treatment plant located at the site on Old Coach Road, providing a higher quality treated wastewater. The treatment process will likely be the Modified Ludsak-Ettinger (MLE) process, although other alternatives proposed by tenderers will be considered. Solids separation and disinfection will be provided by membrane filtration. High flows will bypass the main treatment process, and will receive ultraviolet (UV) disinfection before being discharged into the outfall pipe. The design of the treatment plant has taken into account the seasonal population by including two parallel treatment trains so that capacity can be increased as needed during peak summer flows, and has been designed to provide full treatment for the peak summer population in 2041. Note that bypass treatment is no longer proposed and that all wastewater will receive full treatment
  • a new polyethylene discharge pipeline along Old Coach Road Treated to the start of a new harbour outfall at Childrens Bay, so that treated wastewater can flow by gravity from the new treatment plant to the outfall
  • a new 2.5km long polyethylene (PE) harbour outfall pipe will extend from Childrens Bay, with a diffuser located at 9.5m depth
  • decommissioning the existing wastewater treatment plant on the Takapūneke Historic Reserve.

The whole project is estimated to cost about $30 million, including the new treatment plant, new harbour outfall, new terminal pump station and upgrades to the existing pump stations and pipeline that runs through Akaroa.

Further information about the consent application

Reasons for the project, the consent process, the harbour outfall, the possible effects and how these will be managed.

Consents

The resource consent for discharge from the existing treatment plant to the harbour was renewed 2013 for seven years, to allow time to get all the consents for the new plant and to build it. The resource consents for the Akaroa wastewater scheme were lodged in June 2014, as required by the consent for the existing discharge. The consent hearing was completed in May 2015 and the Hearing Commissioners' decision was received in July 2015.

Consents were granted for the wastewater treatment plant, terminal pump station and reticulation, but not for wastewater discharge from the harbour outfall and other associated consents. The Council has lodged an appeal to the Environment Court, and Ngāi Tahu has joined that appeal.  The full consent application and appendices are:

Why the treatment plant is being moved

The current Akaroa wastewater treatment plant is located at Takapūneke Historic Reserve. In 1830, Te Rauparaha, with the help of the captain of the British Ship the brig Elizabeth, captured the Rangatira (chief) of the maori pa, Te Miharanui, and massacred up to 200 of his people on the site.

It is now widely acknowledged that construction of a wastewater treatment plant at this site was an act of particular cultural insensitivity. The Council now recognises the area as an historic reserve, and hopes the site will become a National Reserve, in recognition of its significance.

The Council is working with Ōnuku Rūnanga to develop a management plan for the site. Discussions have commenced with Ōnuku Rūnanga to seek their views about the deconstruction and demolition of the existing treatment plant and these works will be included as part of the whole project.

The location of the new treatment plant

In December 2011, the Council accepted recommendations from the Akaroa Community Wastewater Working Party and Akaroa/Wairewa Community Board, which reviewed different options for future wastewater treatment and the location of a new plant.

The working party recommended two general locations for the plant – one north of Akaroa and one to the south. The northern site was chosen in October 2012 as it was closer to areas that may be used for irrigating treated wastewater in the future, is closer to Akaroa where reclaimed water could possibly be used in home gardens or toilets, and had better road access and power supply than other sites that were considered. This site was supported by Ōnuku Rūnanga.

The Council has purchased land at the top end of Old Coach Road for the new treatment plant site. Landowners of all suitable sites in the Akaroa vicinity were approached with the offer to negotiate a sale, and only one to the north of Akaroa agreed to do so.

Discharge to Akaroa Harbour

The treatment plant proposed for Akaroa will produce virtually clear water that looks just like tap water and has almost all of the bugs (bacteria and viruses) killed off. The treated wastewater will be safe for irrigation or flushing the toilet. Having a modern, high quality treatment plant in Akaroa will further reduce the risks to public health that may be associated with older wastewater systems, for example shellfish gathering and swimming in the harbour. Akaroa Harbour will remain a great place for tourism, aquaculture and recreation.

There are always bacteria and viruses in the water in the harbour, particularly after rainfall, coming from farm run-off and waste produced by warm-blooded creatures such as geese, dogs, seabirds, possums, marine farming activities as well as from wastewater discharges. Treated wastewater from the new plant will have almost all the bugs killed off, so it will contribute even less to the mix than it has in the past. The treatment plant will also be designed to remove nitrogen, which might otherwise stimulate undesirable algae growth in the harbour. Both the treated wastewater and the outfall pipe will be checked and monitored to ensure discharges meet all environmental regulations, and the harbour ecology and sediment are unaffected.

The outfall pipe will go into the middle of the harbour so it will be about 2.5 km out from Childrens Bay. This compares with the current outfall pipe, which only goes out 100 metres. It will be up to the contractor to decide how to install the outfall pipe, but given the relatively calm environment of Akaroa Harbour, it is likely that a trench will be dug and the pipe placed in it. The trench would fill up with sediment over time. The outfall pipe will be fully buried over its whole length in Council land and roadway and out into the harbour in Childrens Bay. The location of the outfall has been discussed with the Harbourmaster to ensure there is no conflict with cruise ship mooring sites.

Appearance

The treatment plant will include concrete tanks, and a building to house noisy equipment (e.g. pumps) and the membranes. The tanks and equipment buildings for the treatment plant will have a very small footprint (approximately 65 m by 20 m) on this small (approximately 1 hectare) site. To minimise the height of the plant, some of the tanks will be partially sunk into the ground. All surrounding areas of the plant will be extensively landscaped with native plants grown from seeds sourced from nearby bush. This will include tall evergreen trees to screen the treatment plant and ensure visibility from Akaroa and Old Coach Road is reduced as much as possible. The plant will be set back into the hillside.

A new pump station will be needed in Akaroa to pump wastewater to the treatment plant. This will be located in the car/boat park next to Childrens Bay, backing onto the mini golf course. The pumping station will also include fine screens and a grit removal system to remove solids from the incoming wastewater before it is pumped up the hill to the treatment plant for further treatment and disinfection. The terminal pump station will be in a building. Landscaping around the terminal pump station will eventually mostly obscure it from view.

Noise

Wastewater treatment plants do have some noisy machinery but this equipment will be inside a concrete building. The treatment plant will meet the noise limits in the Banks Peninsula District Plan, and the nearest house is 250 metres away. The terminal pump station will also be designed to meet the noise limits in the Banks Peninsula District Plan, and to minimise noise as much as possible for the neighbouring mini golf course. There should be no disturbance to any nearby residents.

There will be some noise during construction due to the heavy machinery needed for construction. To minimise the effects of noise, construction work will be generally limited to Monday to Saturday 6:30am to 8:00pm, with no work on Sundays or Public Holidays. Some work outside of these hours may be necessary to avoid significant disruption to traffic or for contractor and public health and safety reasons (e.g. for sewer connections when flow is typically lower (at night) to limit risk of overflows, or in areas where excavations cannot be left open and is not practicable to temporarily fill in) or for environmental reasons (e.g. to enable critical construction works in relation to stream and groundwater levels due to the tide and a forecast of severe weather). Neighbours to the works will be advised in writing in advance and noise and vibration will be minimised as far as practical.

Odour

Modern wastewater treatment plants don’t produce any odour under normal operating conditions. The parts of the treatment plant that can be odorous will be covered and the air extracted and passed through a biofilter to treat the odour. The terminal pump station will be in a building and the air from this will also be extracted and passed through a biofilter to treat the odour. Contingency plans will be developed to deal with any adverse effects if there is a plant breakdown.

Beneficial reuse of treated wastewater

Reusing resources is good for the environment and Akaroa is short of water in summer so we’re looking at future options to reuse the treated wastewater for irrigation, flushing toilets and home gardening. A large area of relatively flat land would be required if most of the wastewater was to be irrigated to land, and there is a limited amount of suitable land near Akaroa. Nevertheless, we’re investigating options and Lincoln University are undertaking experiments on soil cores taken from Akaroa to determine how much treated wastewater could be sustainably irrigated in the future.

However, there would always need to be a discharge to the harbour during large storm events when flows to the treatment plant are at their highest, due to stormwater inflow and groundwater infiltration into the wastewater pipes. Council is working to reduce the inflow and infiltration, but this is an expensive exercise and experience elsewhere has shown that it is extremely difficult to eliminate entirely.

Costs

The whole project is estimated to cost about $30 million, including the new treatment plant, new harbour outfall, new terminal pump station and upgrades to the existing pump stations and pipeline that runs through Akaroa. The costs for the new wastewater plant will be spread over all Christchurch City Council ratepayers and there will be no targeted rates for Akaroa users. The Council does not have targeted wastewater rates for any areas.