Around 136,000 households are connected to the Christchurch wastewater system, which collects some 150 million litres of wastewater each day through some 1,400 km of pipes, predominantly running alongside or under our City's streets. The pipes and 78 sewer pumping stations collect our untreated wastewater and pump it to the plant at Bromley where it is purified through a thorough treatment process. Treatment includes separating out the organic and inorganic solid material, removing the odours and killing the bacteria and viruses present in the untreated wastewater which arrives at the plant. At present treatment removes 85 per cent of organic material and 99.9 per cent of the bacteria in untreated wastewater. These figures will be higher once the programme to improve the treatment plant is finished.
Domestic customers pay for their use of the service through rates.
The system takes an average of 600 litres of wastewater per day from each Christchurch domestic customer. The treatment process removes most contaminants from the wastewater. When thoroughly treated, this substance becomes an inoffensive soil-like product, suitable for reuse as fertiliser and soil conditioner. It has particular value as an organic compost for its nitrogen, phosphorus and potassium content. Christchurch produces approximately 3,500 dry tonnes of biosolids each year.