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 132.5 miles of sewer lines eight 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 and again in 2009. The plant currently operates under a 5MGD permit. The plant currently operates well below its permitted flow rate, averaging 1.6 MGD for the year 2014.
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 convert 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 microorganism population. The remaining biosolids processed and removed to be used in the Land Application Program, through which they are added to the soil as fertilizer for farmers enrolled in the City's program.
The remaining flow continues through the plant where it passes through filters that help remove any remaining solids. As it approaches the outfall, the flow passes through a chlorine contact basin where chlorine is added to help remove undesirable materials. Sulfur dioxide is then added to remove the chlorine before the flow enters into the receiving waters of Clark Creek.