Michigan environmental regulators have scheduled a virtual public hearing for 6 p.m. on 21 October on a proposed permit that would let treated wastewater from The Barn, a 2.2 million-square-foot hyperscale data center being built for OpenAI and Oracle in Saline Township, be discharged into the Saline River, according to a report published 12 September by MLive.com.
Key takeaways
- Michigan EGLE will hold a virtual public hearing on 21 October on the proposed NPDES permit for The Barn data center, according to MLive.com.
- Developer Related Digital is proposing an average discharge flow of 15,750 gallons per day of treated sanitary wastewater from an estimated 450 on-site employees, according to MLive.com.
- Written comments on the proposed permit are being accepted by EGLE until 23 October through the MiEnviro Portal, according to MLive.com.
- The proposed treatment train includes a flow equalization zone, aerobic reactor trickling filter, sludge holding tank and ultraviolet disinfection, according to MLive.com.
What happened
The Barn data center is under construction in the northwest section of the site, north of U.S. 12/Michigan Avenue between Willow and Case roads, near the Saline River, according to MLive.com. Because the plant would discharge treated sanitary wastewater directly to a surface water, the project requires a National Pollutant Discharge Elimination System (NPDES) permit from the Michigan Department of Environment, Great Lakes and Energy, according to MLive.com.
Data center developer Related Digital filed a project narrative dated 11 November 2025 proposing an average flow of 15,750 gallons per day, drawn only from the sewage of the estimated 450 employees working on site, according to MLive.com. In the antidegradation demonstration submitted to EGLE by RD Michigan Property Owner I LLC, the firm wrote: "A central (wastewater treatment plant) was chosen because it provides an advanced treatment system with high quality effluent and provides a reliable and higher degree of treatment than individual septic tank systems and will be capable of meeting effluent limits prescribed by the NPDES permit," according to MLive.com.
Related Digital also examined alternatives, including subsurface discharge to groundwater and connections to the Saline city and Bridgewater Township municipal plants, which did not have local support, and noted it could not run a sanitary sewer through land it had purchased in Bridgewater Township because it had agreed not to develop that parcel, according to MLive.com.
State water resources officials with EGLE will present the proposed discharge at 6 p.m. on 21 October on Zoom, with pre-registration available but not required and a dial-in option posted alongside the meeting ID, according to MLive.com. Written comments will be accepted through 23 October on the MiEnviro Portal page for the proposed permit, according to MLive.com.
Specification read
The reported design average of 15,750 gallons per day, from a single shift-equivalent workforce of about 450 people, converts to roughly 60 m³/day, putting the plant in the small decentralized municipal class and well below the 0.1–5 MLD envelope typically handled by packaged activated-sludge or trickling-filter trains, according to MLive.com. Domestic-strength sewage in this size range generally lands in the 200–400 mg/L BOD and 250–500 mg/L TSS band (general industry range, not from the sources), so the proposed train — equalization, aerobic reactor trickling filter, sludge holding, UV disinfection — sits on the lower-load end of a conventional secondary-plus-disinfection scheme rather than a high-rate industrial chain, with no DAF, MBR or ZLD stage indicated in the filing, according to MLive.com. The procurement signal is a new-build NPDES package for a hyperscale campus employee population, not a process-water retrofit, so the supply scope is dominated by civil works, a packaged trickling-filter skid, UV banks and SCADA rather than by heavy biological-reactor metallurgy. For a buyer scoping a similar small-flow, surface-water-discharge package, the live decisions are effluent limits vs. the Saline River's antidegradation demonstration, operator labor for a 60 m³/day works, and whether EGLE imposes stricter nitrogen or phosphorus caps than typical domestic numbers. Plants in this bracket usually run 8–14 months from notice to proceed to mechanical completion and 12–18 months to commissioned discharge (general industry range, not from the sources).
Operators of small municipal and industrial sites eyeing a similar NPDES route will recognize the configuration described in our coverage of the Rama 9 data centre wastewater discharge case from Sept 2026, and equipment specifiers working across adjacent loads can compare packaged-train economics in our guides on DAF vs Clarifier for Industrial Organic Chemicals Wastewater and DAF vs Clarifier for EV/Auto Wastewater in Bradenton, FL; the broader project category is captured on our Municipal water and wastewater hub.
FAQ
What is the proposed daily discharge from The Barn data center? Related Digital is proposing an average of 15,750 gallons per day (about 60 m³/day) of treated sanitary wastewater from roughly 450 on-site employees, according to MLive.com. Industrial process water is not part of this permit.
What treatment equipment is in the proposed train? A flow equalization zone, aerobic reactor trickling filter, sludge holding tank and ultraviolet disinfection, according to MLive.com. No DAF, MBR or zero-liquid-discharge stage is named in the filing.
How long do packaged NPDES plants of this size typically take to build? A packaged 50–100 m³/day secondary-plus-UV plant usually runs 8–14 months from notice to proceed to mechanical completion and 12–18 months to a commissioned discharge permit (general industry range, not from the sources).
How can a buyer or resident comment on the proposed permit? EGLE is accepting written comments through 23 October on the MiEnviro Portal page for the proposed permit, and the virtual hearing is scheduled for 6 p.m. on 21 October with pre-registration available but not required, according to MLive.com.
