Wastewater Treatment Division

The 2007 Wastewater Annual Performance Report is now available.  
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The City of Newton Public Works and Utilities Department views environmental protection as one of its top priorities. For this reason, the City actively participates in the collection, treatment and disposition of sewage generated within its boundaries.

Wastewater (sewage), discharged by customers, flows to city owned and operated wastewater treatment plant through a sanitary sewer system encompassing approximately 105 miles of sewer lines; three pump stations and a series of force mains. Upon arrival at the treatment plant all wastewater is treated and discharged in an environmentally safe manner in accordance with the National Pollutant Discharge Elimination System guidelines.

Clark Creek Wastewater Treatment Plant completed in 1979 and upgraded in 1992 has the capacity to treat 7.5 million gallons of wastewater per day. The plant currently operates well below its permitted flow rate, averaging 3.44 million gallons for the year 2000. The Clark Creek WWTP received the EPA operations excellence award in 1989.

Treatment Start to Finish

All wastewater entering the Clark Creek Wastewater Treatment Plant is lifted by influent lift pumps and then flows by gravity to the remaining treatment processes. Initially, wastewater passes through bar screens and grit collectors for removal of debris and sand before proceeding to the primary settling tanks for removal of heavy organic solids and grease.

Lighter organic solids and soluble material require biological conversion to a solid residue for their removal. Commonly referred to as the "Activated Sludge Process", microorganisms cultured within the aeration basins use the organic matter as food and converts it to solid material which is then settled out of the flow stream in the secondary clarifies. Air, required by the microorganisms, is supplied by four motor driven blowers. In addition, nitrification (the conversion of ammonia to nitrate nitrogen) is provided in the aeration basins. Denitrification (conversion of nitrate nitrogen to inert nitrogen gas) also occurs in the aeration basins. A portion of the settled biosolids from the secondary clarifies is recycled to the aeration basins to maintain the microorganisms population, and the remaining biosolids are sent to reuse.