What's happened so far? (archives)
The City Council has had to make decisions about the Ocean Outfall at various stages of the project. Information about those decisions follow and act as an archive for the project.
The wastewater working party
In 1996 a working party with about 15 members, reflecting a wide range of interests, was established to:
- Collate and link needs, issues and ideas in relation to the treatment and disposal of Christchurch’s wastewater.
- Identify the issues to be addressed, assess reports and recommend one or a number of described potential solutions to the Christchurch City Council.
The final outcome of the working party was delivered to the Council in May 2000.
- A strong majority preferred an ocean outfall (with appropriate treatment) as the way to achieve a long-term sustainable wastewater system.
- A minority preferred a long-term consent for an Estuary outfall.
Recommendations were:
- Long-term planning is needed to achieve the long-term goals. Achieve a long-term sustainable system.
- High standards are needed from the wastewater; a number supported at least meeting the contact recreation standard for faecal coliforms in the discharge
- We must not use the environment to clean up wastewater – high quality wastewater is emphasised.
- Environmental outcomes must be achieved.
- Must aim for reuse of wastewater products wherever possible.
- Research, particularly of new field data, is essential.
Christchurch City Wastewater Discharge Issues and Options October 1998.
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Application for consent to continue Estuary discharge
In June 2002Environment Canterbury (ECan) granted a short-term resource consent to discharge wastewater from the treatment plant into the Estuary for five years only. The decision included conditions relating to:
- the quantity and quality of the discharge,
- sampling and contaminant limits, and
- monitoring water quality in the Estuary.
The commissioners implied they wanted Christchurch City Council to stop discharging effluent into an ecologically fragile estuary and instead to put it directly into the ocean.
In November 2003, ECan granted the City Council until 2009 only to continue discharging Christchurch's wastewater into the Estuary.
After considering the recommendations of the working party and various experts plus input from the public, the Council decided that the best option was to continue discharging wastewater via the Avon-Heathcote Estuary, as part of a $30 million plan to upgrade the treatment plant.
The Council applied for consent to discharge up to 500,000cu m of wastewater a day into the Estuary, for 15 years.
Four independent commissioners considered the consent application on behalf of ECan. The application attracted more than 2500 submissions, with 270 submitters asking to appear at the hearings.
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Expert Review Groups
In September 2002, following the commissioners’ decision to award the Council only five more years disposing into the Estuary, two expert review groups were formed to discuss the future direction of Christchurch’s wastewater.
Both groups were asked a series of questions:
- Where should the treated wastewater be disposed of - estuary or ocean?
- What levels of treatment are required?
- What would be the effects of taking the wastewater out of the Estuary?
- What are the likely adverse effects of the wastewater on both the Estuary and ocean?
The Ecological Expert Group recommended that the treated wastewater should be disposed of into the ocean because:
- Even though the wastewater is highly treated, there is reliable information that the discharge enhances the growth of nuisance algae and that concentrations of ammonia in the wastewater are problematic.
- The removal of the discharge from the Estuary may potentially result in very large reductions in algal growth and the piles of decomposing drifting sea lettuce could be greatly reduced. The input of freshwater with the discharge probably also affects the ecology of the Estuary.
The Public Health Expert Group also recommended that the treated wastewater should be disposed of into the ocean, because:
- This solution caters for city growth.
- It recognises a conflict between waste discharge and recreational users as valid users of the Estuary.
- There are other options for discharge, but only one estuary available for recreation within the city.
- It gives greater certainty of maintaining consistent recreational water quality.
- It provides a buffer between the treated wastewater and people.
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Alternative disposal environments
A number of alternative environments have been considered for disposing of Christchurch’s wastewater, including:
- Waimakariri River
- poor environmental outcome
- expensive
- Groundwater injection
- looked unlikely to be feasible in Christchurch situation
- Land
- agricultural and forestry use, landscape reuse considered
- potential risks to groundwater users
- large amounts of land required
- very expensive
- landscape reuse only seasonal solution and for small quantity
- Estuary
- chosen as short-term option in first round
- low dilution rate
- water quality criteria can be met with UV disinfection
- Ocean
- improved dilution
- away from population
- water quality standards can be met
- estimated up to 50% reduction of sea lettuce growth in estuary
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Alternative treatments
The Council also looked into a number of alternative treatments for Christchurch’s wastewater, including:
- Satellite Treatment Plants
- would not improve the quality of discharge from treatment plant
- economic costs very high
- consenting of all facilities and a range of disposal environments required for each area
- Aquaculture
- technically possible
- benefits uncertain
- costs high
- environmental risks high
- Drinking water
- technically possible
- extremely expensive
- social acceptability low
- Nutrient Removal
- options of removal of nitrogen, phosphorus or both
- various methods
- desired water quality could be met without these methods at this time
- expensive
- Disinfection - ultra-violet, chlorination and ozone
- ozone very expensive
- chlorination not acceptable
- UV considered as a means of meeting desired outcome for Estuary water quality
- Ponds or wetland
- modifications to the ponds possible to increase water quality
- extending wetlands would require very large area of land not available
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Community workshop on water quality outcomes
Participants were invited to a workshop in July 2003 to discuss what they expect in terms of water quality with the building of a pipeline out to sea to dispose of the city’s wastewater.
A cross-section of Christchurch interests, including fishing and recreational groups, Employers Chamber of Commerce, Crown Public Health and community board representatives, as well as South Brighton residents were invited to the workshop. Organised by the Christchurch City Council, the workshop involved engineers and scientists presenting up to date information to the group, who then gave the Council feedback on what their expectations were.
Feed back from the Water Quality Outcomes Community Workshop
Key concerns identified by the groups included:
- Swimming and surfing without fear of getting ill
- Regular, independent monitoring of wastewater as it moves from the Christchurch Wastewater Treatment Plant, through the pipe to the outfall and back to the beach
- No added pollutants in the water or disruption to the food chain
- No visual plume from the air
- Safe shellfish gathering on the beach
- No smell from the discharge.
General statement from the community at the workshop:
- Ensure there are no discernable effects on people from the treated wastewater
- Achieve a “Very Good” Ministry for the Environment (MFE) beach standard within Five years of commissioning the pipe
- Address other sources of contamination
To ensure safe swimming and playing in the surf zone and on the beach the workshop said they wanted:
- To swim and play safely in the surf zone and the water quality to meet contact recreation standards, to a standard that shellfish would be safe to eat at all times.
The City Council advises:
- Shellfish gathering will be safe at all local beaches, except within the Estuary.
- The recreation environment will be cleaner for people using the ocean, beaches and Estuary than now and will meet MFE standards.
Smell from the Christchurch Wastewater Treatment Plant and oxidation ponds
The workshop: Responses ranged from “Levels of odour should be acceptable to locals” to “Zero odour”.
The City Council advises: The upgrade of the treatment plant has added further odour control measures. When this upgrade is complete, all major sources of odour will have been treated and the load on the ponds will be lowered significantly, ensuring the ponds do not emit significant odours.
To give reassurance of good water quality management the workshop said it wanted:
- Extensive, independent monitoring
- before discharge at the end of the oxidation pond
- above the outfall
- at the beach
- between outfall and beach.
- A watchdog group, involving local residents, to be kept informed.
The City Council advises:
The Council will undertake comprehensive water quality and environmental testing in conjunction with an independent audit group, including community representatives. This will be a consent condition.
Results expected in the mixing zone where treated wastewater and seawater mix the workshop said it wanted:
- No visible plume (trail) from the air other than the contrast of saltwater mixing with freshwater, and no other effects.
The City Council advises: With present committed treatment improvements to the wastewater, there will be no visible plume other than the change due to the mixing of sea and fresh water.
The protection of sea floor life and fish
The workshop said:
- Treatment needs to ensure adequate control of toxins and solids by ensuring fish are protected, preventing toxic accumulation for perpetuity. Make sure the ecology is protected.
The City Council advises: With existing committed treatment improvements:
- Solids and contaminants are controlled and removed by the treatment processes to comply with environmental standards.
- Concentrations of ammonia and heavy metals will be so low, as to not affect fish.
- The revised Trade Waste Bylaw will achieve further reductions in heavy metals and other industrial contaminants.
Achieving safe water contact in the general recreation area
The workshop said:
- No agreement was reached on what was needed to have safe water contact in the general recreation area. Residents favoured a range of results in the general recreation area:
- Safety standards for swimming should be met above the outfall and diffuser area at all times.
- Shellfish gathering standards should be met on the surface above the pipe outfall.
- The wastewater coming out of the pipe should be safe to swim in.
The City Council advises: With existing committed treatment improvements:
- The recreation environment will be cleaner for people using the ocean.
- The wastewater coming out of the pipe will meet Ministry for the Environment standards for contact recreation.
- Within a few hundred metres of the pipe there will be reduced diversity of some underwater creatures and increased abundance of other species.
- The shellfish-gathering standard will be met at all ocean beaches (but not in the Estuary).
- Shellfish and the surrounding environment will be as clean as now
- Ocean fish stock will not be harmed from wastewater contaminants. The Estuary recovery will be underway and consequently fish will benefit.
Beach gradings and water quality
The City Council advises:
- The beach grade for local beaches with the wastewater currently discharged into the Estuary is “Poor”. One is graded “Very Poor”.
- With an ocean outfall, all beaches from New Brighton to Scarborough and those inside the Estuary will be rated “Good” once the Major Sewer Upgrade is finished. A good beach grade means the beaches will easily meet the Ministry for the Environment guidelines for contact recreation.
- As with all urban communities, stormwater and other pollutants (via rivers) are ongoing and prevent attainment of “Very good’’ water quality, even when the treatment plant discharge is removed from the Estuary.
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Assessment of Environmental Effects
The City Council lodged its resource consents application to build a 3km Ocean Outfall into Pegasus Bay with the Canterbury Regional Council (ECan) on Friday, 17 December, 2004.
A major part of the resource consents application presented to ECan includes an Assessment of Environmental Effects (AEE) prepared by URS, consultants to the Council for this consent application. This report details URS’s findings regarding the Ocean Outfall’s likely impact on the surrounding environment.
The Technical reports (Volumes 1 and 2) are 29 individual report which are appendicies of the AEE, and referred to throughout the AEE. The Technical Reports are not available on this website due to their size. They are available at a cost on request by email from waste@ccc.govt.nz or phone 941-8666.
View the AEE report
 These documents are PDFs. You will require the free Adobe Reader to view them.
Assessment of Environmental Effects - the full document [6MB]
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Council decision on pipe length and UV
The Christchurch City Council gave the go ahead in July 2004 for the construction of a 3km Ocean Outfall pipeline to take the city’s treated wastewater out to sea.
It also decided not to proceed with the building of an artificial ultra-violet (UV) disinfection plant. However, work would be done to ensure a plant could easily be added later if such a plant becomes necessary.
The report to the City Council at its meeting on 29 July considered the results of public consultation earlier this year, studies of ocean-current modelling and ecology, results from the recently completed upgrades to the oxidation ponds and cost considerations.
Click here for more information.
To view a copy of the report considered by the City Council at its July meeting see: www.ccc.govt.nz/council/proceedings/2004/july/cnclcover29th/ and go to the Report of the Sustainable Transport and Utilities Committee: Ocean Outfall
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Resource consents to build and operate an ocean outfall
On 2 November 2005, the Environment Court granted all the consents sought to build and operate the Ocean Outfall subject to conditions.
Later in November after a detailed examination of the 381-page decision the Council decided to appeal a small number of the conditions to ensure that the Council could confidently comply with all conditions.
The Council then negotiated with other interested parties about some of the proposed changes. Resource management law encourages parties to try to reach agreement which is then reviewed and approved by the Court.
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Awarding of contracts
Pipeline contract
In September 2006, New Zealand based company McConnell Dowell Constructors Ltd, was awarded the contract for the construction of the City's Ocean Outfall pipeline.
McConnell Dowell recently completed the construction of the Waimakariri ocean outfall and currently, is building the Clandeboye (near Temuka) and Tahuna (Dunedin) outfalls. The company has a strong track record in this type of work and a sound local knowledge of Pegasus Bay.
Not only was this the best option financially for the City, it was the most environmentally sound and least disruptive solution for the local community and recreational users in the vicinity of the pipeline route.
The tender process
Following a publicly advertised Registration of Interest and selection process for the pipeline contract in October 2005, a short-list of five tenderers was established, including local and overseas companies.
Draft tender documents were issued to selected tenderers in February 2006, prior to an interactive tender process which involved a briefing session, site visit, and interviews with the tenderers in early March 2006.
Following receipt of feedback and discussions with the tenderers, tender documents were finalised and issued at the end of March 2006.
Tenders closed on 7 June 2006.
Pump station contract
The construction of a pump station is required for this project and was tendered separately. Documentation was issued in mid-May 2006 with the tender closing on 22 June. The contract was awarded to Works Infrastructure Ltd in September 2006.
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