Council authorizes short-term oxygen treatment for sewer lagoons after sludge, odor concerns

The Gunnison City Council voted to authorize an immediate, temporary treatment of the city's sewer lagoon to address heavy sludge buildup and rising hydrogen sulfide odors.

Garrett Willem, who spoke at the start of the sewer item, told the council the city had successfully drained and dried Cell 1 and that most incoming wastewater is now going into Cell 2, which has less surface area and is not providing enough oxygen for normal biological processing. "When the bugs don't have enough oxygen...that creates hydrogen disulfide," Willem said, adding that the smell is already noticeable and solids are beginning to accumulate.

Willem recommended a shock treatment using a proprietary oxygen-bearing solution supplied by Wastewater Innovations, saying the product "turns the bugs on and gets things processing." Staff provided a cost estimate of $4,000 for installation and commissioning and $4,000 per month for ongoing dosing, with an option to increase the dose for an additional $1,000 per month if needed. Willem said the treatment would be used only until Cell 1 can be cleaned and returned to service, and that city staff will pursue a wastewater study and CIB-listed capital improvements to reconfigure cells for better processing.

Councilman Peterson moved to proceed with the short-term treatment and Councilman Childs seconded the motion. The council discussed funding the work from the sewer budget and noted that Mayor Leatherwood indicated he had a credit the city could apply toward the cost. Council requested a three-month review of results. The motion passed on a unanimous voice vote.

The council directed staff to proceed with the treatment, monitor the odor and sludge levels, provide cost updates, and return with results to the council after approximately three months or earlier if the situation changes.