Wastewater Treatment

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, also known as a water reclamation facility to emphasize the beneficial reuse potential of the treated wastewater. Sanitary sewer systems carry only domestic and industrial wastewater, while combined sewer systems also carry stormwater runoff. At the treatment plants, the wastewater is purified and returned to the environment to be reused.

The North Shore Water Reclamation 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 water reclamation facilities with a combined average design capacity of 63.4 million gallons a day and over 100 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 water reclamation facilities passes through a series of five major treatment processes. In addition, the solids produced by the wastewater treatment processes are treated and disposed of separately. Wastewater treatment requires an intricate balance of physical, biological, and chemical processes which are described below.

• Preliminary Treatment includes screening to remove large objects (such as sticks, rags, leaves, and trash) and the settling of grit (inorganic material such as sediment, sand, stones, etc.) which could clog pipes and disable treatment plant pumps downstream. The screened material is collected and disposed of at a municipal landfill, while the wastewater flows to primary treatment.
• Primary Treatment involves the removal of the settled and floating solids. Solids removed from this process are treated in the solids handling portion of the plant.
• Secondary Treatment utilizes naturally occurring microorganisms which digest organic material, reduce nutrients, and eventually settle as solids.
• Tertiary (or Advanced) Treatment is used to further improve the quality of the water. Deep bed sand filters are used to significantly reduce the suspended solids and further purify the wastewater. After tertiary treatment, over 90% of solids have been removed from the wastewater.
• Disinfection is the final step in the wastewater treatment process. Ultraviolet light disinfects the treated water before it is discharged into the receiving water body to protect the public from exposure to pathogens. The Waukegan Water Reclamation Facility (WRF) and Gurnee WRF discharge treated effluent to the Des Plaines River and the Clavey Road WRF located in Highland Park discharges treated effluent to the Skokie River.
• Solids Handling involves the treatment of the biosolids removed from the wastewater treatment processes. The solids that are removed during the wastewater treatment processes still contain a large amount of water so to reduce the volume of solids and disposal costs, the solids are thickened and then dewatered by belt filter presses. The dewatered biosolids are then loaded into trailers and transported to the Zion Biosolids Recycling Facility for drying prior to disposal.

History of the North Shore Water Reclamation District

In the early years of the 20th Century, Lake County, especially the communities along Lake Michigan, was a booming place. Highland Park and Lake Forest were prosperous, fast-growing suburbs. Waukegan and North Chicago had developed into major manufacturing and commercial centers. And Fort Sheridan and the Great Lakes Naval Training Center were bustling military bases, gearing up for action as World War I loomed.

For the most part, infrastructure improvements kept pace with the growth of these lakefront communities, except in one critical area - wastewater treatment. Most of the towns along Lake Michigan discharged partially treated or untreated sewage and industrial waste directly into the lake, which, of course, was also the main source of drinking water for those same communities.

To address this major health hazard, community leaders from across eastern Lake County came together to urge the creation of a local wastewater treatment agency. In 1911, the Illinois General Assembly enacted legislation to establish the North Shore Sanitary District, which went into operation in 1914.

From its early days of treating sewage for 36,000 residents in six lakefront communities, the NSWRD now serves more than 300,000 people in 17 communities throughout Lake County including: Winthrop Harbor; Zion; Beach Park; Waukegan; Gurnee; Park City; Grayslake; North Chicago; Green Oaks; Lake Bluff; Lake Forest; Highwood; Bannockburn; Deerfield; Highland Park; Fort Sheridan; and the Great Lakes Naval Training Center. The NSWRD works in close conjunction with these municipalities, which collect wastewater from residents via local sewer systems, which in turn is transported to the District via over 100 miles of interceptor pipes. The District's other key missions are to protect local waterways, including the region’s most precious natural resource, Lake Michigan, and develop beneficial uses for treated wastewater (effluent), including enhancing green spaces in the region.

During its first 60 years, the NSWRD operated nearly a dozen wastewater treatment plants. Since 1975, the District has consolidated its operations into three state-of-the-art facilities in Waukegan, Highland Park & Gurnee, which, on average, treat nearly 50 million gallons of wastewater each day. The three plants have all been recognized for excellence by the National Association of Clean Water Agencies.

The District faced perhaps its greatest challenge in the 1960s and 1970s with the enactment of the Federal Water Quality Act of 1965 and the Clean Water Act of 1972. The NSWRD could no longer discharge treated wastewater, or effluent, into Lake Michigan, and it undertook major infrastructure improvements to comply with the new stringent environmental laws. Lakefront treatment plants were converted to pumping stations, which moved wastewater away from Lake Michigan to the three regional treatment plants. Treated effluent is now discharged into the Des Plaines and Skokie rivers and is often cleaner than the water already flowing in those two waterways.

Originally, the five-member Board of Trustees was appointed by the Chief Judge of the Lake County Circuit Court. In 1975, an amendment to the NSSD Act divided the District into five wards and gave voters the right to directly choose Trustees, making it only one of three wastewater treatment agencies in Illinois with a Board directly accountable to the voters – and, of course, customers – of the District.

To better reflect its mission of defending and preserving our natural resources and its dedication to the beneficial reuse of our water resources, the North Shore Sanitary District changed its name to the North Shore Water Reclamation District in 2014. For over a century, the NSWRD has achieved an outstanding record of protecting the environment, especially Lake Michigan, due to both consistently upgrading its infrastructure and the diligence of the clean water professionals who work for the District.