AlexRenew finished the RiverRenew combined sewer overhaul serving Alexandria, VA, on June 29, a project that is expected to keep 120 million gallons of wastewater out of Virginia waterways each year, according to a 5 September 2026 report from the Bay Journal. The headline figure, the eight-year build and the June handover were confirmed by the outlet in its coverage of the state's long-running effort to cut overflows from 19th-century combined sewer systems.
Key takeaways
- AlexRenew completed the RiverRenew overhaul of Alexandria's combined sewer system on June 29, 2026, meeting an extended deadline of July 1, 2026 by a few days, per the Bay Journal.
- The project is expected to keep about 120 million gallons of combined-sewer overflows out of Virginia rivers each year, the Bay Journal reports.
- RiverRenew includes a 130-foot-deep, 2.2-mile deep-storage tunnel, an interceptor sewer, diversion facilities, wastewater plant upgrades and a 12-story underground pumping station, according to the Bay Journal.
- The Virginia Department of Environmental Quality estimates 23 million gallons of sewage are released into state waterways each year, the Bay Journal reports.
- Richmond still has the most annual overflows among Virginia cities at 2,585 million gallons, with Lynchburg also still upgrading, the Bay Journal reports.
What happened
AlexRenew's RiverRenew programme rebuilt Alexandria's combined sewer system, a 19th-century layout in which a single pipe carries both sewage and stormwater, the Bay Journal explains. Under heavy rain, those systems are designed to overflow into nearby rivers, and the Virginia Department of Environmental Quality estimates 23 million gallons of sewage reach state waterways each year, the Bay Journal reports.
The Alexandria upgrade is built around a 130-foot-deep, 2.2-mile tunnel that captures overflow and holds it until it can be treated and released, supported by an interceptor sewer, diversion facilities, wastewater plant upgrades and a 12-story underground pumping station, according to the Bay Journal. Construction took eight years, with the tunnel-boring machine Hazel and twin wide shafts already on site in July 2022, the Bay Journal reports.
AlexRenew completed the overhaul on June 29, meeting the extended 1 July 2026 deadline "by just a few days," the Bay Journal reports. The scheme is expected to hold roughly 120 million gallons of combined-sewer overflow out of Virginia rivers each year, the outlet adds. Richmond and Lynchburg are still working on their own combined sewer upgrades, with Richmond recording the largest overflow volume in the state at 2,585 million gallons a year, the Bay Journal reports.
Specification read
The headline scale is 120 million US gallons per year of avoided combined-sewer overflow. Converting to operator units, that is about 454,200 m³/year, or roughly 1,244 m³/day of wet-weather load that will now reach the headworks instead of the river (calculated from the reported 120 million-gallon figure; the source does not give a daily flow). The 2.2-mile (about 3.5 km) storage tunnel and 130-foot (about 40 m) shaft work as a deep equalisation buffer ahead of the existing plant, so the bearing stage is the collection-and-conveyance / preliminary-treatment end of the train: screening, grit removal and primary clarification feed a buffer that is then pumped up through a 12-story lift station to secondary biological treatment (typical configurations: A2O, MBR or MBBR for nutrient removal, with SBR and UASB as alternatives for smaller plants) and a tertiary/disinfection step before discharge (general industry range, not from the sources).
For buyers, the event is a benchmark for what a wet-weather CSO scheme can deliver per dollar of tunnel and pump-station work, not a new technology purchase. If your plant is a municipal combined-sewer utility running in the low thousand m³/day range with frequent wet-weather overflows and a regulatory consent decree or CSO long-term control plan in force, the Alexandria case confirms that the bottleneck is usually storage plus high-head pumping back to the headworks, and that the biological and disinfection stages are reused rather than re-specified. HydropureWater supports projects of this class through its Municipal water practice and its Integrated Sewage Treatment product line, and buyers scoping similar work can compare screening and primary-clarifier choices against our DAF vs Clarifier guide for mining and metals wastewater in Nome (2026) and the DAF vs Clarifier guide for Columbia (2026); more context sits on our Industries We Serve page.
FAQ
What is the headline environmental benefit of the RiverRenew project? AlexRenew expects to keep about 120 million US gallons (roughly 454,200 m³) of combined-sewer overflow out of Virginia rivers each year, per the Bay Journal. The source does not give a daily flow figure or a discharge-quality number.
How long did the Alexandria tunnel take to build, and when was it finished? The eight-year build was completed on June 29, 2026, beating the extended 1 July 2026 deadline "by just a few days," the Bay Journal reports. Lead times for large-diameter CSO storage tunnels typically run five to ten years including planning, design and commissioning (general industry range, not from the sources).
What were the main physical components of the upgrade? The scheme centred on a 130-foot-deep, 2.2-mile storage tunnel, an interceptor sewer, diversion facilities, wastewater plant upgrades and a 12-story underground pumping station, according to the Bay Journal.
Are other Virginia cities still working on their combined sewer systems? Yes. Richmond and Lynchburg are still upgrading, and Richmond has the largest annual overflow volume in the state at 2,585 million gallons, the Bay Journal reports. Capital programmes of that scale are typically procured in multiple bid packages over several years (general industry range, not from the sources).
