Metro Water Recovery outlines heat-recovery, phosphorus-removal and PFAS concerns to Arvada council

Mitch Conway, CEO of Metro Water Recovery, told the Arvada City Council on Sept. 9 that the regional wastewater agency treats wastewater from roughly 2.2 million people across about 850 square miles and that it operates two large treatment plants and about 200 miles of interceptor pipe. He described current resource-recovery work — converting solids to methane for electricity, piloting phosphorus-precipitation called MagPrex to produce a fertilizer, and testing heat-recovery to serve district heating and cooling — as ways to reduce operating costs and create new revenue streams.

Conway said Metro treats about 140 million gallons of wastewater per day at plants in Commerce City and Brighton, and that its staff of about 500 aim to protect public health and the environment. On the solids side he said the agency produces just under 100 tons of biosolids daily, dewaters that material and applies it to farmland, including a roughly 50,000-acre farm near Deer Trail. He said captured methane currently offsets about 40% of the agency’s electrical load.

Conway described two innovations Metro is pursuing: MagPrex phosphorus precipitation, which he said was the largest installation of its type in the world and creates a fertilizer product that is now being composted and may be sold if it meets quality standards; and heat recovery, which extracts thermal energy from wastewater and could be used in district heating and cooling projects such as the National Western Center. Conway said heat capture might be large enough to serve substantial downtown steam-loop needs if built out, and staff would share a heat-map of pipeline temperature/density with Arvada staff.

He warned that regulatory demands are increasing costs dramatically. Conway said Colorado Department of Public Health and Environment (CDPHE) discharge-permit requirements and EPA limits are pushing Metro toward advanced tertiary treatment that would produce near-drinking-water-quality effluent; a slide noted $1,290,000,000 of projected capital expenditures over 10 years (Conway said that figure was likely outdated and that Metro’s updated planning was closer to $1.5 billion). He said Metro’s 2024 capital and operating budget was "about a 130 [million]," debt service was "about 50 [million]," and sewer tap fees were about $57,000,000 in 2024, while annual charges were discussed but the transcript figure was not specified precisely.

Conway flagged PFAS as an emerging, expensive contaminant problem. He said PFAS arrive in wastewater from many consumer and commercial products and that Metro cannot now remove PFAS at scale. He said the EPA has declared PFAS a CERCLA contaminant and that designation could create broad cleanup liability if regulators require removal of PFAS from wastewater effluent and biosolids. Conway said Metro’s advocacy work seeks a water/wastewater exception or other relief from federal cleanup liability and that the more effective long-term solution is removing PFAS from commerce and products rather than paying to remove it repeatedly at treatment plants.

Council members asked technical and operational questions. Council member Pfeiffer asked whether Metro would sell heat to downtown customers; Conway said potential partners could include Xcel Energy and the City and County of Denver and that partnerships would be required. Pfeiffer and Rupert asked about the scale of heat available; Conway said a single major line could represent heat produced by roughly 100,000 people in a district and that Metro estimated up to about 200 megawatts of thermal energy across its system if all effluent heat were captured. Rupert asked whether smaller local exchanges might be feasible on Sheridan; Conway said Metro had mapped lines and would share a heat map with city staff.

Conway described workforce and infrastructure challenges, saying many operators are approaching retirement and Metro is working with high schools and community colleges on recruiting and training, and that Metro is beginning partnerships with workforce-training centers and other agencies. He described a One Water/One Environment approach that tries to weigh water treatment, energy use, chemical inputs and community affordability together when evaluating investments.

The presentation concluded with Conway offering to send Metro’s heat map to Arvada staff and with council members expressing interest in receiving that material and in workforce-training follow-ups.