By: Laura Novitzki, Environmental Association for Great Lakes Education (EAGLE)
Have you noticed beach advisory signs on Lake Superior or on the St. Louis River warning swimmers and other recreationalists not to enter the water? Signs are posted by the County Health Department when water samples are found to contain high levels of E. coli and fecal coliform bacteria – a hazard that occurs when raw sewage is periodically released into water bodies. These bacteria can cause gastroenteritis – an illness displaying symptoms of nausea, vomiting, abdominal cramps, fever, headache, and diarrhea. Other illnesses can include eye, ear, nose, and throat infections. In 2003, Douglas County posted 14 beach advisories and closed beaches 8 times due to increased levels of bacteria.
For the past several years, the Western Lake Superior Sanitary District (WLSSD) has experienced sewage overflows into Lake Superior and the St. Louis River after heavy rainfall and from snowmelt. Rainwater infiltrates sewage pipes, overloading capacity and causing untreated sewage to be released into water bodies. According to WLSSD, other reasons for overflows have included electrical and control system issues, power outages, and pipeline failures due to corrosion.
Sewage overflows are illegal under the federal Clean Water Act. On January 12th of this year, the Environmental Protection Agency (EPA) sent out an order for WLSSD to find ways to completely eliminate sewage overflows. Under the order, both the City of Duluth and WLSSD had 60 days to submit a work schedule and formulate a plan to stop the overflows. Prior to January 12th, WLSSD was operating under a five-year permit issued in 2002 by the Minnesota Pollution Control Agency (MPCA) to “control or eliminate” overflows at 18 separate locations. Plans for how to follow the new order are in the works, but according to Kurt Soderberg, executive director of WLSSD, they are hoping for more public comments.
So how does the whole system work? There are two sewer systems – the sanitary sewer, which is designed to carry wastewater from houses and businesses to WLSSD where it is treated and released into the St. Louis River, and the storm sewer, which carries rainwater and snowmelt directly into creeks, rivers and lakes without being treated. The problem with sewage overflows lies with Inflow and Infiltration (I&I). Inflow refers to clear water from rain and snowmelt that improperly drains into the sanitary sewer system. Infiltration refers to groundwater that leaks into the sanitary sewer system through cracked or faulty sewer pipes. During heavy rainfall, I&I cause the sanitary sewers to fill beyond capacity, mixing clear water with untreated sewage.When sewer pipes become filled, the combination of clear water and untreated sewage backs up through pipes and overflows onto city streets, eventually ending up in Lake Superior and the St. Louis River. According to WLSSD, the largest sources of inflow are from individual homes and businesses with drains that send rainwater directly into the sanitary sewers.
One significant way to solve overflow issues is to reduce the amount of runoff water going into the city’s sewer systems. Wetlands and stormwater ponds allow runoff to filter through the soil and slowly flow into streams. Natural wetlands are disappearing as land is developed and not enough attention is given to stormwater management on these development sites. Impervious surfaces such as parking lots and roof tops cause runoff water to flow quickly into drainage systems.This sudden flush of water stresses stormwater sewers, causing them to overflow. This water carries many contaminants from yards, streets, and leaky septic systems.
To solve power outage and electrical and control system issues,WLSSD is considering the installation of back-up power generation systems at four of its main pump stations and at its main treatment plant, which would allow the sewage system to operate during a major power outage. The cost for installing these systems totals approximately $4.2 million and WLSSD has requested federal funding to help cover costs. The cost for not installing them also appears high. According to WLSSD, in 2003 alone, more than 4.9 million gallons of sewage were released into Lake Superior and the St. Louis River due to power failures and electrical problems at pumping stations. Although back-up generators would solve some of the overflow problems, they would not solve them completely.With little public input, WLSSD’s board is not yet convinced that this is the best use of their money. The City and WLSSD are also looking into installing sanitary sewer overflow storage basins.
Your input is needed now! Help the City and WLSSD solve overflow problems and let them know that any measure taken to reduce sewage overflows is money well spent. Contact Joe Stepun, WLSSD Manager of Environmental Services, at 740-4806 or firstname.lastname@example.org to offer your suggestions.