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.
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.
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.