Every year up to 12.9 billion litres of wastewater is collected from 25,300 connections around the city. 26 pumping stations help move the wastewater along a network of pipes (150mm to 1500mm in diameter) that if laid on end would stretch 358 kilometres long.
Most of the wastewater is delivered to the Tōtara Road Wastewater Treatment Plant, where the majority of contaminants are removed before it is passed through wetland ponds for further treatment and then discharged to the Manawatū River.
During low flows in the river the wastewater is further treated to remove dissolved phosphorus, which contributes to algae growth in the river. The present wastewater treatment plant has the capacity to serve a population of 100,000.
Laboratory tests are conducted regularly to ensure compliance with resource consent conditions.
How our waste is treated
Inflow and infiltration
Inflow and infiltration refers to rainwater and groundwater that gets into the wastewater pipes from broken sewer mains and house connections and from improperly connected stormwater systems. A common point of entry for stormwater into the wastewater network is through a gully trap. Council is actively trying to reduce inflow and infiltration.