Sewage Treatment Plant Water Treatment Plant Supervisor - Kevin Godfrey Water Treatment Technicians - Andrew Cutfield/Kevin Crosby Phone: 06 377 4527 Fax: 06 378 7850 Mobile: 0274 426 456 The Masterton District Council's sewage treatment facilities are situated at Homebush 4 kms east of Masterton. It would appear that the first treatment was undertaken around 1900 with a septic tank situated at Nursery Road, fed by a 450mm earthenware pipe. In 1914 the sewer was extended to the Homebush area close to the present location of the oxidation ponds, and a larger septic tank and sludge lagoons were constructed. Due to continuous rain in the winter of 1970, ground saturation had caused a large amount of stormwater infiltration to enter the sewer system, and resulted in problems with the treatment plant. It was becoming apparent that a new treatment plant would have to be built, and consultants were engaged to design a plant suited to the needs of the District through to 2020. The report from the consultants anticipated that ten years after the ponds were commissioned, it would be necessary to introduce primary treatment. Present System The wastewater treatment at present is by means of oxidation ponds built in 1971. Three ponds cover a total area of 26.3 ha. The majority of the sewage is gravity fed from the town by way of a 900mm pipe. The flow is split into the first two primary ponds, each approximately 8.5ha in area, then into a tertiary pond of 8.6ha. From the tertiary pond the flow discharges over the outfall into the Makoura stream, and from there into the Ruamahanga River. The Council presently treats an average flow of 25,000m3/day. Present Process Sewage is collected from a population of almost 19,000 living in an area of 1796ha. There are two small pumping stations and one syphon lines in the system, but the majority of sewage is gravity fed to the treatment plant. Testing treated sewage With the Resource Management Act now in place and the growing public awareness of water quality, the Masterton District Council is investigating possible options for improving the effluent discharge. A three stage upgrade is being implemented. Stage I, completed in 1991 was a fine screening and aeration facility along with operations, building and laboratory. This improvement has increased the capacity of the plant and the quality of the final effluent. Plastics and solids are taken out of the flow at the step screen, fed into a dewatering press, and then collected in a trailer for disposal in a landfill. The two primary ponds have 2 aerators each, located in strategic positions and used periodically to increase oxygen levels in the ponds. Stage II of the proposed upgrade is the proposed installation of an aerated lagoon upstream of the oxidation ponds to accommodate additional use in the future. This will be constructed if and when demand requires. Stage III is to be additional treatment to improve the quality of the current plant discharge. A task group is currently studying the various options for upgrading the sewage treatment system. Monitoring Monitoring of dissolved oxygen, suspended solids, pH and temperature is done daily. Laboratory analysis of discharge effluent is done by Works Consultancy Services on a regular basis. Flows, faults and equipment status are relayed through a radio telemetry system to a central computer. Sewerage Upgrade