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EGLE and the city of Lansing continue decades-long partnership to reduce combined sewer overflows
October 14, 2019
For nearly three decades, the Michigan Department of Environment, Great Lakes, and Energy (EGLE) and the city of Lansing have worked together using the Clean Water State Revolving Fund (CWSRF) to help reduce raw sewage discharges into the Grand River and Red Cedar River. To date, Lansing has secured 23 low interest loans from EGLE totaling nearly $250 million to work on the goal of separating its combined sewers. The completed projects have eliminated an estimated 952 million gallons of raw sewage from entering these local waterways each year.
Lansing, like many cities throughout the state and country, has a combined sewer system. Combined sewer systems are called combined because they take both sewer discharges from houses and businesses (sanitary) and stormwater from streets and sidewalks. This can become problematic when large rain events occur because the pipes reach capacity and/or more water is sent to the treatment plant than can be effectively treated and disinfected. It also adds additional costs and burdens the treatment plant by forcing it to treat rainwater. When this happens, untreated wastewater is discharged with limited or no treatment. These discharges are referred to as combined sewer overflows (CSOs).
There are two main approaches to resolving CSOs:
- Eliminating the CSOs through sewer separation by adding a second sewer pipe strictly for the sanitary sewage while the “old” sewer pipe directs the stormwater to surface water (such as a creek or river) so it does not cause capacity issues in the sewer system; or
- Through adequate treatment of the overflows, which is typically accomplished by building large underground retention treatment basins that treat and disinfect the overflows or store the sewage until after the rain event when the treatment plant has the capacity to treat it before discharge.
Lansing has chosen the first option and has been utilizing CWSRF loans to separate the combined sewers throughout the city primarily due to the added benefit of reconstructing aging roadways within the city concurrently.
Lansing received its first CWSRF loan in 1992 and is currently working on its 23rd. The loan money has been strictly for CSO work, but Lansing has leveraged the projects by adding its own money to fix drinking water pipes, curbs, gutters, streets, and sidewalks throughout the process. As of the current loan, approximately 70% of the total CSO land area has been separated and 22 of the 41 combined sewer structures have been abandoned. By the end of the projects, an estimated 1.65 billion gallons of raw sewage per year should be eliminated from discharge to the Grand River and Red Cedar River.
EGLE is proud of the successful partnership with Lansing on the removal of its CSOs from the Grand and Red Cedar rivers. Additional information on the projects and the specific items addressed to date can be found on the city’s website.