The City of Bettendorf had to flush nearly 129 million gallons of sewage into the Mississippi River last month to prevent the Waste Water Treatment Plant in west Davenport from being overwhelmed by sewage, combined with a large volume of storm water that had seeped into Davenport and Bettendorf sewer lines.
The "Sanitary Sewer Overflow Events" began June 30, with eight large pumps transferring sewage from the backed-up sanitary sewer lines into storm water pipes, which flow into the Mississippi River. The pumps ran from June 30 until July 13, according to the report filed by the city with the Iowa Department of Natural Resources (IDNR).
Cities must contact the IDNR when it begins "bypassing" sewage treatment by pumping into the river, and it must report the total amount bypassed once the pumping ends. The city filed its report with the state July 15.
The cities of Bettendorf and Davenport jointly own the wastewater treatment plant, located along the Mississippi River near S. Concord Street, Davenport. Both cities last year signed a consent agreement with the IDNR which calls for more than $160 million in sewer system improvements over the next 20 years to reduce storm water infiltration into sewer lines and improve the processing capacity of the treatment plant.
Last year, a similar situation occurred last year when heavy rainfall led to Bettendorf pumping 200 million gallons of untreated sewage, diluted with storm water runoff, into the river between March and June.
The city of Davenport, because it operates the waste water treatment plant, makes its report on sewage bypassing at the end of the month.
