Wastewater
The City Council provides a wastewater system to collect and treat all wastewater and permitted industrial wastes in a way that meets public health and effluent discharge standards.
There are four separate sewer networks operated by the Council:
- Palmerston North
- Ashhurst
- Aokautere
- and Linton
Treatment is provided at three facilities:
- Totara Road Treatment Plant
- Ashhurst Oxidation Ponds
- and Aokautere Oxidation Ponds
Collection and treatment
Each year some 12.9 billion litres of wastewater from the city is collected by a network of pipes and delivered to the main treatment plant in Totara Road. Here the sludge is removed before the resulting effluent is passed through lagoons for further treatment and then discharged to the Manawatu river.
The present treatment plant has the capacity to serve a population of 75,000 persons. The Council’s laboratory maintains a close check on wastewater effluent to ensure compliance with the resource consent conditions.
A separate network of pipes and a small treatment facility services Ashhurst with another small system at Aokautere.
Facts and figures
- Number of connections: 25,300
- Volume of wastewater: 12.9 billion litres per year
- Length of main pipelines: 358 km
- Pipe sizes (diameter): 150mm to 1500mm
- Pumping Stations: 22
- Treatment facilities:
- Totara Road Treatment Plant
- Ashhurst Oxidation Ponds
- Aokautere Oxidation Ponds
Grease Trap Consents
Grease build-up is a major contributor to the reduction in the capacity of the city’s sewers. Grease and oils are also extremely difficult to process at the Treatment plant. This is why grease must be prevented from entering the wastewater system.
The New Zealand Building Code requires that:
- In buildings other than housing grease traps will be provided where wastewater is likely to contain grease.
- All food premises in Palmerston North that prepare food for sale are required to have a suitable grease trap for the volume of waste discharged and to hold a grease trap consent that is renewed annually.
For further information about suitable grease trap design and details of the grease trap consent contact the Customer Service Centre.