The Wastewater Treatment Plant consists of two pre-aeration cells, three aerated lagoons, and two polishing ponds with secondary treatment through utilization of slow sand filtration prior to final discharge into the Green River.
The City of Green River residents generate about 1.0 million gallons of sewage each day (about 75 gallons per person). Most of the sewage flows downhill through a 55-mile network of underground pipes that end up at the Wastewater Plant. Using bacteria and air, the plant converts raw sewage into treated wastewater that can be returned safely to the Green River. Here's how:
Bar Screen Machine: Raw sewage flows through screens that remove most objects larger than ¾ of an inch.
Grit Basins: Sewage flows through a 20-foot deep tank. This allows sand, grit, and other heavy particles to settle to the bottom. Later, they are removed.
Aeration Cells and Lagoons: Supplies large amounts of air to mix the wastewater and bacteria. The air speeds the growth of helpful microorganisms which already exist in the wastewater to consume harmful organic matter in the wastewater. It is the job of microorganisms to "eat" the waste materials contained in the wastewater. Some microorganisms which may be involved in a treatment system are bacteria, protozoa, and algae. Microorganisms are the work horses of the process, accounting for about 85% of the treatment. Polishing lagoons allow microorganisms to settle at the bottom of the lagoon before discharging the treated wastewater to the river.
Laboratory: Several analyses must be conducted to monitor the contents of the wastewater and to make sure that treatment methods are working correctly. The results must meet federal and state standards. Monthly we must send all the results to the Department of Environmental Quality and the Environmental Protection Agency.