Christchurch treated wastewater discharge consent monitoring

Resource Consent CRC051724 allows the discharge of treated wastewater from the Christchurch wastewater treatment plant into the Pegasus Bay coastal marine area via an ocean outfall located 3kms off shore and 17m below the water surface.

Samples of the treated wastewater discharged through the ocean outfall are taken and analysed for a range of contaminants as shown in the table below.

Weekly	Fortnightly	Six monthly	Annually
Temperature	Nitrate nitrogen	Arsenic	Salmonella
pH	Nitrite nitrogen	Cadmium	Campylobacta
Dissolved oxygen	Total Kejldahl nitrogen	Chromium	Giardia
Five-day biochemical oxygen demand, BOD	Total phosphorus	Copper	Cryptosporidium
Filtered BOD	Dissolved reactive phosphorus	Lead	Human enterovirus
Total suspended solids		Nickel	Human adenovirus
Faecal coliforms		Zinc	Organochlorine pesticides
Enterococci		Mercury	Organophosphate pesticides
Escherichia coli			Polychiorinated biphenyls
Ammoniacal nitrogen			Polycyclic aromatic hydrocarbons

The resource consent contains a range of thresholds for these contaminants, which when exceeded further investigation or remedial action is required.

This consent year

Every quarter (November to January, February to April, May to July, August to October) we submit a monitoring report to Environment Canterbury with all of the samples taken for that time period.

• Quarterly Monitoring Report - November 2024 to January 2025 [PDF, 858 KB]
• Quarterly Monitoring Report - February 2025 to April 2025 [PDF, 827 KB]

At the end of each year we submit an Annual Report which has all of the information presented each quarter. These reports can be viewed at the end of this page in the expandable section.

Environmental monitoring

Weekly water samples are taken from the following beach locations: South New Brighton Beach at Jellicoe Street, Sumner Beach at the surf club and New Brighton at the surf club. These samples are analysed for faecal coliforms and enterococci and again thresholds apply.

At five-yearly intervals, a collection of marine sediment samples are taken. These samples are analysed for total organic carbon, total nitrogen, total phosphorus, arsenic, cadmium, chromium, copper, lead, mercury, nickel and zinc.

The benthic invertebrates in these samples are also surveyed. Again threshold levels apply. Monitoring data is presented to Environment Canterbury for review at various intervals, quarterly, annually and five yearly as the sampling is required.