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.
Sample results of the water discharged through the Ocean Outfall [PDF, 249 KB]
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.
Sample Results for beaches closest to the Ocean Outfall [PDF, 122 KB]
Quarterly samples of shellfish (tua tua) are obtained from South New Brighton Beach at Jellicoe Street, the south end of Rockinghorse Road and Sumner Beach at the surf club. These are analysed for E. coli and human enterovirus.
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.