Wastewater schemes

There are three types of wastewater schemes provided by the Council - gravity, STEP and pressure. 

Gravity Schemes

Wastewater service is provided via gravity through piped reticulation to a large treatment plant often with pump stations within the reticulated area.

For any properties with an on-site septic tank within an urban service area, the tanks are generally owned and maintained by the individual property owners, including any cleaning.

STEP Schemes

Wastewater service is provided by a Septic Tank Effluent Pumping (STEP) system.

Raw sewage is collected in private on-site septic tanks where it receives primary treatment and screening.  The primary treated effluent is then pumped to a treatment plant. The on-site septic tanks are owned and maintained by the individual property owners while the common rising main and treatment plant is owned and operated by the Council.

Pressure Schemes

Wastewater service is provided by a pressure sewer system.

Raw sewerage is collected in privately owned on-site pump stations. These contain a macerating pump which breaks up the raw sewerage into a slurry before pumping into the Council-owned mains through to the treatment plant. 

WDC Schemes

Scheme No. of Properties Sewer service Type Initial Treatment Plant Primary Treatment
Rangiora 13,190 Gravity Rangiora Oxidation ponds
Kaiapoi Gravity and pressure
Kaiapoi Aerated lagoon, oxidation ponds and wetlands
Pegasus Gravity and pressure
Woodend Aerated lagoon with wetlands (Woodend)
Woodend Gravity   Woodend Aerated lagoon with wetlands  
Woodend Beach Gravity   Woodend Aerated lagoon with wetlands (Woodend) 
Waikuku Beach Gravity and pressure
Waikuku Beach Oxidation ponds with wetlands
Pines Kairaki Gravity   Kaiapoi Aerated lagoon, oxidation ponds and wetlands (Kaiapoi)
Tuahiwi STEP Woodend Aerated lagoon with wetlands (Woodend)  
Mandeville STEP
Rangiora Oxidation ponds
Oxford
807
Gravity Oxford Activated sludge
Loburn Lea
 38 Gravity Loburn Lea Recirculating sand contactor
Fernside
21 STEP Fernside Recirculating sand contactor
TOTAL 14,056      

The Eastern District Sewer Scheme comprises of  Rangiora, Kaiapoi, Pegasus, Woodend, Woodend Beach, Waikuku Beach, Pines Kairaki, Tuahiwi and Mandeville wastewater schemes. The Eastern District Sewer Scheme discharges to the Ocean Outfall in Pegasus Bay. All other schemes discharge to ground.