The treatment plant in its current position below Koromiko Crescent (accessed off Otamuhua Lane) was constructed in 1988. It treats wastewater from Diamond Harbour, Church Bay and Charteris Bay.
Sewage receives primary and secondary treatment within the plant followed by ultra-violet (UV) disinfection before being discharged through an outfall pipeline into the harbour. Sludge is regularly removed and transported to the Christchurch Wastewater Treatment Plant.
The main resource consent for discharge to the harbour (CRC101835) expires in 2021. The Council has a programme of works planned for completion in 2022, that will see this plant decommissioned, with all of the raw wastewater from Lyttelton Harbour being pumped directly to the Christchurch Wastewater Treatment Plant.
Resource consent CRC101835 sets out requirements for monitoring treated wastewater and the area receiving the discharge (receiving environment). Samples are taken and analysed on a regular basis. The volume of wastewater leaving the plant is recorded continuously. Together these provide an indication of how the plant is performing and whether there are any potential adverse effects of the discharge on human health or the environment.
Monitoring data is provided in the tables and graphs linked to below:
Annual report on monitoring data CRC101835 Diamond Harbour wastewater treatment plant - annual report 2015/16 [PDF 693KB].
Annual report on monitoring data CRC101835 Diamond Harbour wastewater treatment plant - annual report 2014/15 [PDF 669KB].
Annual report on monitoring data CRC101835 Diamond Harbour wastewater treatment plant - annual report 2013/14 [PDF 643KB].