Wastewater volumes processed in Christchurch City.

General

Description Measure
% of Christchurch population on a reticulated wastewater system
(the remainder in rural areas have septic tanks and other on-site systems or a weekly nightsoil collection)		 99.9%
Number of households currently serviced by Christchurch Wastewater Treatment Plant  147,000 (approx)
Length of time wastewater takes from kitchen sink to Christchurch Wastewater Treatment Plant
(amount of time varies from an hour to almost a day depending on distance from Christchurch Wastewater Treatment Plant)		 Maximum 24 hours (gravity systems only)
Average life of pipes 94 years
Gravity sewer system replacement cost (2015) $2,458 million
% wastewater volume domestic (2013) 30%
% wastewater volume commercial/industrial (2013) 20%
% wastewater volume infiltration 50%

Pipework

Description Measure
Length of public pipe reticulation system 1,814 km
Longest single stretch of pipe (from furthest point to Christchurch Wastewater Treatment Plant) 20 km
Smallest diameter pipe used (gravity sewer) 90 mm
Largest diameter pipe used (gravity sewer) 1.8 m
Length of gravity sewers 1615 km
Length of pressure pipes (gravity system) 199 km
Number of manholes 30,817

Pumping

Description Measure
Number of pumping stations 180
Number of lift stations 56
Number of vacuum stations 3
Number of odour control stations 34 (12 at pump stations, 22 standalone)
Number of pipelines leading from terminal pumping stations to Christchurch Wastewater Treatment Plant 5
Total capacity of terminal pumping stations to Christchurch Wastewater Treatment Plant 6,610 l/s (litres per second)
Number of radio repeater stations 10
Number of monitoring stations 37

Treatment

Description Measure
Average wastewater inflow to Christchurch Wastewater Treatment Plant (includes septic tank sucker trucks) 172,000,000 L/day
Rag (screenings) removed from wastewater 1 tonne/day
Grit removed from wastewater 2 tonnes/day
Dried biosolids produced (includes Christchurch, Akaroa, Wainui, Duvauchelle Bay, Tiako Bay, Wainui, Lyttelton, Diamond Harbour, Governors Bay) 9 tonnes/day
Power produced 35 MWh
Wastewater treatment plant replacement cost (includes Akaroa, Duvauchelle, Tikao Bay, Wainui, Lyttelton, Diamond Harbour, Governors Bay and Christchurch Wastewater Treatment Plants) (2015 valuation) $511 million