A coalition of environmental groups has reportedly sued the Metropolitan Water Reclamation District of Greater Chicago (MWRD) under the Clean Water Act (CWA), alleging that the treatment authority’s discharge of phosphorous and untreated sewage has caused excessive algae growth and low oxygen levels in the Chicago River. NRDC v. MWRD, No. 11-2937 (N.D. Ill. filed 5/3/11).

The complaint alleges that untreated sewage enters the river during large-scale rain events due to the outdated design of the district’s sewage treatment and combined sewer overflow systems, and seeks an injunction to halt the discharges.

The complaint further asserts that the discharges are causing oxygen levels to drop to “dangerously low” levels, affecting fish populations and contributing to “unnaturally high” algae levels; alleges CWA violations and seeks penalties of $37,000 per day of violation. Plaintiffs filed a notice of citizen suit with EPA, the Illinois EPA and Illinois attorney general, as required by the CWA, 60 days before filing the citizen suit. See BNA Daily Environment Report, May 10, 2011.