Feilding Wastewater Treatment Plant Upgrade
The Feilding wastewater scheme is the largest in the District and serves a number of large industries as well as more than 14,000 residents.
Parts of the Feilding wastewater network date back to 1905. The Feilding wastewater treatment plant (WWTP), located on Kawakawa Road to the south of Feilding, was built in 1967. Prior to this plant being built, sewage was treated in a large septic tank.
The treatment plant has been upgraded over the years in response to increasing domestic/industrial demand and more stringent environmental standards. Significant reductions of loads discharged to the river have already been achieved: DRP (99%), E.coli (98%), CBOD5 (35%) and suspended solids (70%). Remaining upgrade works will target further significant reductions in SIN (ammonia and nitrate N) and optimisation of irrigation to maximise land application.
Currently, the WWTP includes key process elements such as screening, anaerobic and aerated lagoons, sedimentation, clarification and UV disinfection. The existing sludge stream from the sedimentation basins is processed by digestion prior to thickening and stabilisation via storage in sludge lagoons.
New resource consents have been granted and the Manawatu District Council will dispose of a significant proportion of treated effluent from the WWTP onto land. When discharge to land is not possible, treated wastewater is stored (two storage ponds with a total capacity of 25,000 m3 have been constructed). The last option would be to discharge to the Oroua River.
The shift to land disposal will also underpin Council's commitment to the Manawatu River Accord and local iwi by removing a significant volume of treated effluent which is currently discharged into the Oroua River.
Several major projects are underway to increase the treatment capacity and to create a more robust treatment system. Those include a receiving facility to separate industrial streams from the main treatment processes and to be treated directly in the digester (also being upgraded), sludge dewatering equipment, irrigation system, composting or improved clarification and DRP removal.