On 3 September 2026, reporting tied a months-long bacterial contamination of Cheyenne, Wyoming's reclaimed water system to subcontractors building Meta's $800 million "Project Cosmo" AI campus, who routed cooling-system wastewater into the city's sanitary sewer and triggered a permanent discharge ban Yahoo. The city cited the operation for "serious noncompliance," permanently revoked discharge privileges, and barred closed-loop cooling wastewater from the municipal system indefinitely, with a $10,000 fine Yahoo.
Key takeaways
- More than 800,000 gallons of fill-and-flush cooling wastewater from Meta's Project Cosmo site passed through Cheyenne's sanitary sewer before the contamination was caught Yahoo.
- Routine sampling of the reclaimed water system in early 2026 identified Cupriavidus gilardii, a rare metal-resistant soil bacterium The Guardian.
- Cheyenne's Board of Public Utilities cited the operation for "serious noncompliance," permanently revoked discharge privileges, and issued a $10,000 fine Yahoo.
- Drinking water was not affected; the contamination stayed in the non-potable reclaimed system used for irrigation Yahoo.
- Cheyenne adopted a new policy prohibiting closed-loop and fill-and-flush cooling wastewater from data centers, requiring separate collection tanks and offsite disposal The Guardian.
What happened
The contamination was discovered in February 2026 during routine testing of wastewater discharged into public sewers from the cooling system of the data center campus in the High Plains Business Park The Guardian. Officials identified Goat Systems LLC, a Delaware-based contractor on the 800,000 sq ft facility known as Project Cosmo, as being responsible, while Fortis Construction was named as the on-site general contractor The Guardian. Fortis said it stopped discharging immediately and that its own independent tests found no trace of the bacterium; the city's account involves white bacterial colonies in petri dishes Yahoo.
Cupriavidus gilardii is a naturally occurring bacterium found in soil, regarded by health experts as an "opportunistic pathogen" harmful only to people with existing serious health conditions or weakened immune systems The Guardian. "The concern we have with our reuse system is we put it into aerosol, where we spray it on to the grass, and that increases the potential for health issues," said Frank Strong, BOPU's engineering and water resource division manager The Guardian.
The new regulations adopted by Cheyenne require companies using closed loop cooling systems to build and implement separate collection systems that direct water from cooling equipment or associated floor drains into storage tanks and offsite disposal, rather than flushing it into the city's sanitary sewer The Guardian. The city's irrigation program had resumed once the data center's wastewater was no longer being discharged The Guardian. In a statement, a Meta spokesperson said, "When the board shared that it found a substance in the city's wastewater - not public drinking water - Fortis immediately stopped discharging industrial wastewater and began hauling it offsite" The Guardian.
Specification read
Scale check for a procurement engineer: 800,000 US gallons is roughly 3,028 m³ discharged in a single event, or about 3.0 MLD if spread over one day, against a 300,000-gallon-per-day (~1,135 m³/day) typical hyperscale data center water demand reported in the same coverage The Guardian. The class of wastewater here is construction-phase fill-and-flush liquor from a closed-loop cooling system, carrying pipe scale, flux residue, construction debris, and any metal-resistant biofilm that colonised the new pipework before flushing The Guardian. The treatment train this stream belongs in runs from oil and grit removal to equalisation, then biological reduction (MBR or MBBR) sized for low-COD but variable metals loading, with cartridge filtration and disinfection upstream of any irrigation reuse, and a brine-concentration step such as high-recovery RO where a reuse permit is the discharge path Water Purification. The event bears specifically on the equalisation and reuse-discharge stages, where BOPU moved from "discharge to municipal sewer" to "tankered offsite disposal" overnight The Guardian. If your plant is sized in the 1-5 MLD range, takes construction or commissioning wastewater from a closed-loop cooling tie-in, and discharges to a municipality with a reuse-for-irrigation permit, the Cheyenne rule means the discharge path is no longer available and the design must include segregated holding tanks plus a contract for offsite disposal from day one Municipal. For sites facing a similar future ban, comparing packaged versus cast-in-place concrete STPs for cooling blowdown is now a board-level decision, not a detail Packaged STP vs Cast-in-Place Concrete STP for Data Center Cooling Blowdown (2026), and where reuse is still the only outlet, ZLD or high-recovery RO is the route to keep ZLD vs High-Recovery RO for Data Center Cooling Tower Blowdown: 2026 Brine Mandate Verdict.
FAQ
What was the fine, and does it change buying decisions?
The reported fine was $10,000 on an $800 million project Yahoo. The procurement consequence is not the fine but the permanent discharge ban, which forces capital spending on segregated tanks and offsite hauling The Guardian. Budget for tankered disposal, not just treatment equipment, from project start.
What is the regulated treatment train for fill-and-flush liquor?
Reported coverage describes fill-and-flush water as carrying construction debris, flux residue, and pipe scale The Guardian. The standard train is screening, oil and grit removal, equalisation, biological (MBR or MBBR), and tertiary filtration with disinfection before any reuse or discharge Water Purification. For a reuse-for-irrigation permit, expect pathogen and metals monitoring on top.
How long does it take to install a segregated collection and offsite disposal system?
No lead time is reported in the sources. For packaged equalisation and treatment skids, a general industry range of 8-16 weeks from PO to commissioning applies to small plants in this class (general industry range, not from the sources). Civil work for tanks and pipework typically runs 4-8 months for a 1-5 MLD site (general industry range, not from the sources).
Does this set a precedent for other US data center sites?
Cheyenne's rule is local, but US hyperscale sites already number around 4,500 and some consume up to 300,000 gallons of water a day The Guardian. Any municipality with a reuse-for-irrigation permit and a hyperscale build nearby now has a live template for similar restrictions (general industry range, not from the sources).
