The southeast Iowa city of Keokuk has agreed to address discharges of untreated sewage into the Mississippi River. The U.S. Environmental Protection Agency says Keokuk will improve its combined storm water and wastewater sewer system over the next 20 years, reducing discharges of hundreds of millions of gallons of raw sewage into the Mississippi River and its tributaries.

Under a compliance order filed in Kansas City, Keokuk will submit to the E.P.A. and the Iowa Department of Natural Resources a long-term control plan for improving its sewers to reduce overflows. The plan is due no later than December 31, 2012. Once approved by the EPA and D.N.R., Keokuk must complete the implementation of all terms of the order no later than December 31, 2030.

Initial cost projections by the city for total separation of the combined sewer system are estimated to be between $60 million and $100 million.

By Phil Roberts, Davenport