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How The Plants Work

Wastewater (or sewage) originates from many sources, including homes, businesses, schools, and industries, and includes water from showers, sinks, dishwashers, laundries, car washes, hospitals, and food processing operations.  According to the U.S. Environmental Protection Agency, the average American produces 100 gallons of wastewater each day.

 

Most homes, businesses, and institutions are connected to a sewer system that conveys their wastewater to a public wastewater treatment plant.  Sanitary sewer systems carry only domestic and industrial wastewater, while combined sewer systems also carry stormwater runoff.  At the treatment plant, the wastewater is purified and returned to the environment to be reused.

 

The North Shore Sanitary District (District) provides wastewater treatment for the eastern part of Lake County, Illinois.  The District serves over 300,000 residents within its Service Area.  The District owns and operates three advanced sewage treatment plants with a combined average design capacity of 63.4 million gallons a day and over 125 miles of interceptor sewers.  The local collector sewers within incorporated areas of the District’s Service Area are owned by the local municipality.  The sanitary and stormwater sewers within the District’s Service Area are separate systems; therefore, there are no combined sewer systems.

 

The wastewater treated at the District’s sewage treatment plants passes through a series of five major treatment processes.  In addition, the solids produced by the wastewater treatment processes are treated and disposed separately.  Wastewater treatment requires an intricate balance of physical, biological, and chemical processes which are described below.