The Missouri Department of Natural Resources (“DNR”) issued an April 19th Abatement Order on Consent (“Order”) to the City of Mexico, Missouri (“City”) wastewater treatment plant (“Plant”) addressing alleged violations of the Missouri Clean Water Law.

The City is stated to own and operate a wastewater treatment facility consisting of an activated sludge plant with a trickling filter, peak flow basin, anaerobic sludge digestion, effluent re-aeration and ultraviolet warm water disinfection located in Audrain County, Missouri.

The Plant operates pursuant to the terms and conditions of a Missouri State Operating Permit (“Permit”) and treated effluent from the Plant discharges into the South Fork of the Salt River. The Permit includes effluent limitations for cyanide, copper, lead, and zinc.

The Order states that monthly discharge monitoring reports submitted by the Plant to DNR document that the effluent discharge from the Plant failed to comply with the applicable permitted effluent limitations for Total Recoverable Cooper during the first, second, third and fourth quarters of 2014; and the second and third quarters of 2015. Further, a DNR inspection of the Plant allegedly documented that it failed to comply with effluent limits contained in Part “A” of the Permit since October 9, 2013 and failed to meet a scheduled compliance contained in Part “E” of the Permit.

A Notice of Violation was subsequently issued by DNR to the City on February 10, 2014.

The City hired a consultant and prepared a Quality Assurance Project Plan to determine the site specific conditions to provide data for DNR to develop corresponding permitted effluent limits.

The City agrees to submit a Work Plan for purposes of acquiring a dissolved total recoverable conversion factor or data for site specific criteria utilizing a United States Environmental Protection Agency approved methodology for Copper associated with the National Pollution Discharge Elimination System Copper effluent limits which includes a schedule for completion and submission of the report to the DNR.

The City is required to respond to any DNR comments in the Work Plan and upon approval implement it. Upon completion of the Work Plan, the City agrees to submit the results to DNR.

Click here to download a copy of the Order.