The Casper City Council on Tuesday decided to consider revisions to its Municipal Code about the limits of certain pollutants that can be discharged into the systems for sanitary sewers and wastewater treatment plants.

The code needs changing as part of the Clean Water Act, which requires municipalities and industrial businesses to use treatment techniques to reduce or eliminate harmful pollutants to wastewater treatment plants and sanitary sewers, according to a memo to City Manager Carter Napier  from Public Services Director Andrew Beamer and Public Utilities Manager Bruce Martin.

The original industrial pretreatment ordinances were adopted by the city in 1984, and have been revised five or six times since then, Napier said during the council's pre-meeting before its regular meeting.

The city's wastewater treatment plant discharge permit was renewed in November 2018, and that triggered the need to evaluate the local limits of pollutants allowed in the water.

The proposed limits -- measured in milligrams per liter -- for arsenic and cadmium would be loosened, but the limits for nine other pollutants would be lowered.

Those nine are for chromium, copper, lead, mercury, molybdenum, nickel, selenium, silver and zinc.

"The limits for each of the pollutants is based on an in-depth evaluation of current wastewater treatment plant influent loading, state and federal water quality standards, public health standards, and includes a safety factor to protect the publicly owned treatment works," Beamer and Martin wrote.

The proposed limits for arsenic and cadmium can be increased without hurting the treatment process or jeopardizing effluent permit requirements, they wrote.

The city staff who worked on the proposed code revision did not anticipate any industrial users having difficulty meeting the proposed limits, Beamer and Martin wrote.

Council member Steve Cathey asked if the Wyoming Game and Fish Department is aware of and approves of the proposed changes.

Beamer said the department has no problem with the proposed revisions.

With no other questions, and an informal authorization from the council, Napier said he will have his staff draft an ordinance to be presented to the council at some time in the future.

According to Beamer and Martin, the U.S. Environmental Protection Agency will receive the proposed updates after the council approves it on a first reading.

That would start a 30-day public notice period. If no substantial comments are received, the EPA will notify its approval with the council, which then can proceed to the second and third readings, according to the memo.

Enter your number to get our free mobile app

7 Wyoming Waterfalls That Are Worth a Road Trip