Meta Cheyenne data center water discharges suspended after rare bacterium contaminates city reclamation supply.

The Cheyenne Board of Public Utilities has halted industrial wastewater discharges from data center operations after identifying a rare bacterium in the city's reclaimed water system. The agency traced Cupriavidus gilardii, a metal-resistant bacterium, to Goat Systems LLC, the contractor Meta uses for its Cheyenne campus development. The discovery rendered two water reclamation plants inoperable for months during cleanup. On March 24, the Board revoked Goat Systems' discharge privileges, and the suspension now extends to all data centers connected to city services.

The contamination occurred during fill-and-flush operations, a commissioning procedure in which cooling-loop piping is filled with water, flushed to remove debris, and then drained. Goat Systems discharged this flush water—containing Cupriavidus gilardii—into Cheyenne's sanitary sewer. Frank Strong, the Board's engineering and water resource division manager, confirmed that the fill water was sourced from the Board itself. Laboratory staff detected the bacterium in February during routine fecal-bacteria sampling, though Strong noted the organism's origin remains unknown. "This isn't something we normally test for," he told the Wyoming Tribune Eagle.

As AI data centers scale globally, sealed liquid cooling systems are gaining adoption as a water-efficient alternative to evaporative cooling. Microsoft markets loops filled once during construction and then recirculated indefinitely, while Nvidia's Rubin platform uses a coolant blend of 75% water and 25% propylene glycol. However, the initial fill—and subsequent flush—generates a discharge that leaves the site before the system seals.

The Board's concerns extend beyond the bacterium itself. Closed-loop systems can accumulate glycol and other chemicals that municipal wastewater plants cannot process. Since Cheyenne applies reclaimed water to parks, golf courses, and landscaping, the Board worried the bacterium could become an aerosol hazard during irrigation. Although Cupriavidus gilardii is not a regulated contaminant, its presence triggered pass-through and interference violations under Cheyenne City Code and federal pretreatment standards.

Meta stated it is working with general contractor Fortis, which stopped discharging and began trucking wastewater offsite. Independent testing by Meta found no trace of the bacterium. Testing at both the Dry Creek and Crow Creek facilities cleared in late June, and the reclamation system resumed operation. Cheyenne City Councilman Pete Laybourn described the disclosure as "a very, very unpleasant surprise." The Board has not disclosed whether the suspension affects other data centers still under construction in Cheyenne.