Sewage overflows in Davenport have fallen from 104 in 2016 to 18 last year thanks to wastewater system improvements in Bettendorf and Davenport mandated under a 2013 consent order with the Iowa Department of Natural Resources (IDNR).
In Bettendorf, only two SSO's (sewage system overflows) were reported in 2017, and none have been recorded as of March 30 this year.
In addition to reducing the infiltration of rainwater into the sanitary sewer system, the capacity of the Wastewater Treatment Plant along Concord Street in Davenport was increased to 55 million gallons per day with a $7 million "optimization" project. That upgrade essentially was completed late last year.
In its annual report to the IDNR, engineering firm Veenstra & Kim stated flows to the wastewater treatment plant after heavy rains now are noticeably lower because of the sewer line upgrades. And, with completion of the high treatment capacity, the plant is able to handle high flows after heavy rains without closing its gates and bypassing untreated sewage into the Mississippi River.
Before the plant and sewage collection system upgrades, system overflows were common after heavy rains.
In 2009, the cities discharged 724 million gallons of partially treated wastewater into the Mississippi River at the treatment plant over 90 days of discharges. In 2010, when the wastewater treatment plant restricted flows, Bettendorf pumped more than 33 millions of untreated wastewater in the river over 11 days.
The discharges prompted the IDNR to put the four communities on notice in 2013 that permits for new housing subdivisions would not be issued if the problem was not addressed.
Consequently, the sewer system owners – Davenport, Bettendorf, Riverdale and Panorama Park – signed an administrative consent order agreeing to a 20-year, $160-million system upgrade plan. Part of that agreement requires the sewage system operators to make an annual report on progress toward the various improvement projects.
CLICK HERE to download the full 2018 update from sewer system operators to the IDNR.
CLICK HERE to download the 2013 Administrative Consent Order between the IDNR and the cities of Davenport, Bettendorf, Riverdale and Panorama Park.
