Resource Recovery and Energy Optimization
- Beneficially reuse 85 dry tons of biosolids per day
- Return nitrogen, phosphorus, and other minerals to land while sequestering carbon
- Maintain Metro Water Recovery’s 52,000-acre farm
- Distribute and land apply biosolids at 379 permitted private farms
- Recovered struvite (crystalline phosphorus product) distributed to composter for generation of specialized high-P fertilizer
- Investigating the recovery and reuse of sulfur for various purposes as part of the renewable natural gas project
- Extract heat from wastewater during cold periods to reduce the treatment plant effluent temperature and offset natural gas heating demand
- Sink heat from conditioned spaces during warm periods into the wastewater to offset electricity demand from HVAC cooling
Anaerobic digestion generates biogas comprised primarily of methane and carbon dioxide that may be recovered for beneficial use such as heat or power generation.
Renewable Natural Gas
- At the RWHTF, a design is underway for a biogas conditioning system to produce renewable natural gas for pipeline injection. This natural gas will provide a renewable fuel source for transportation and consumer heating.
- Electricity is currently generated at both NTP and RWHTF through the combustion of renewable methane. This production offsets 40% of electricity purchases at the RWHTF. Heat is recovered during the process to support process needs and supply building heat for many large process buildings.
- At the RWHTF, additional efforts are underway to increase the reliability of electricity purchased from the utility.
PAR 1265 – Electrical Transmission-Level Service Substation (RWHTF)
2021-2026 Investment: $72.6M
Provide high-voltage, transmission-level electrical connection to the RWHTF to improve reliability, increase operational flexibility, and reduce annual operating expenses.
PAR 1395 – Cogeneration Equipment Replacement (RWHTF)
2021-2026 Investment: $50.7M
Replace the existing combined heat and power (CHP) system with a renewable natural gas (RNG) system capable of treating the biogas to a pipeline quality for injection into Xcel’s pipeline.
PAR 1401 – Alternative Energy Evaluation (RWHTF, NTP, Farm)
2023-2035 Investment: TBD
Develop solar and wind energy at the three large Metro sites, RWHTF, NTP, and METROGRO Farm, in areas were improvements are not anticipated for 20 years or where operations will not be impacted.
Land application of biosolids leads to a reduction of 14,000 metric tons of CO2-eq each year.
Robert W. Hite Treatment Facility
Capital Investments (15 years)
Projects are based on the current anticipated regulatory requirements but are subject to change without notice. Projects are planned and are subject to change without notice including the cost estimates.
Heat Recovery Facilities
Provide heat recovery facilities to supplement heat demands in processes and conditioned spaces across the RWHTF, offsetting natural gas consumption, reducing emissions, and reducing cooling system requirements.
Incorporation of heat recovery systems for use in process building heating to reduce operational and capital costs associated with cooling towers.