| October 20, 2003
News Release Up to 75 percent of the wastewater traveling through King County sewer lines during our heavy winter rains begins that journey as clean water. More than half that clean water enters the sewer system from private property. The rainwater enters the sewer system through cracked pipes, leaky manholes, or storm drains, downspouts and sump pumps that shouldn't be connected to the sanitary sewer system. "Handling the extra flow is expensive because the clean water ends up being treated like sewage at our two regional treatment plants," said Dan Sturgill, manager of King County's Regional Infiltration and Inflow Control Program. "That extra water in sewer pipes also can cause sewer back-ups and require new, larger facilities to carry and treat the mix of clean water and sewage." The county's Wastewater Treatment Division, in collaboration with 33 local cities and sewer districts, is working to change that. As part of a multiyear program, they are conducting 12 pilot projects to test new, less-invasive sewer rehabilitation techniques and track the costs and logistics of them. The pilot projects are under way with the cities of Auburn, Brier, Kirkland, Lake Forest Park, Mercer Island, and Redmond and the Coal Creek (serving Newcastle), Northshore (serving Bothell/Kenmore), Val Vue (serving SeaTac), Ronald (serving Shoreline) and Skyway (serving West Hill) sewer districts. Some projects are focusing on parts of the sewer system in the public right-of-way. Others are focusing on private side sewers or service lines in cooperation with private property owners. Their common goal is to reduce the inflow of stormwater and infiltration of groundwater -- or I/I -- to the sewer system. A significant objective of the I/I control program is to complete the construction by this fall and evaluate each project's effectiveness in reducing I/I this winter. Wastewater from homes, schools, businesses, factories, office buildings, shopping malls and other locations is actually collected in sewer systems operated and maintained by cities and sewer districts. The wastewater then flows through King County's pipelines to its regional treatment plants in Renton and Seattle. "Local residents can help us reduce this problem," Sturgill said. "Find out where your roof and foundation drains go, and learn if they could be disconnected without creating other problems. If appropriate, redirect the water away from the building and let it soak into the ground." Besides testing I/I control methods in neighborhood projects, the program is designed to do the following:
Last January, the program completed flow monitoring to identify the scope of the problem in the pilot project areas. The program tested for sources of excessive I/I flows coming from public and private property to existing wastewater collection systems. Using TV inspections and smoke testing, work crews last year examined the condition of many public sewer mains in the street and private side sewers from homes and businesses to detect possible sources of excessive clean water flows. For more information about the pilot projects, contact the county's I/I program staff: Erica Herrin, 206-684-1138 or erica.herrin@kingcounty.gov; Mary Lundt, 206-263-3184 or mary.lundt@kingcounty.gov; and Marc Errichetti, 206-263-6070 or marc.errichetti@kingcounty.gov. For more information about the regional program, contact Dan Sturgill, I/I program manager, 206-684-1242 or dan.sturgill@kingcounty.gov; or contact your city wastewater utility or local sewer district. Here's the King County Web site for the program: http://dnr.metrokc.gov/wtd/i-i. King County's Wastewater Treatment Division protects public health and water quality by serving 18 cities, 15 sewer districts and more than 1.4 million residents in King, Snohomish and Pierce counties. The regional utility now operated by King County has been preventing water pollution for nearly 40 years. Related Information
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