What We Do
An elaborate system of underground pipes brings sanitary flow to AlexRenew. The City of Alexandria owns and maintains the small pipes that collect water from businesses and neighborhoods within its boundaries. AlexRenew owns and maintains the large interceptor sewers that transport flows to our treatment facility.
Our interceptors are designed to allow wastewater to flow by gravity to our treatment facility, or route it to one of the five pump stations we operate. At the pump stations, pumps push the flows high enough to flow by gravity to our facility.
Our Water Resource Recovery Facility is designed to treat an average daily flow of 54 million gallons per day and is among the most advanced in the world.
Once flows reach our facility from our interceptor system, they go through coarse screens, fine screens, and grit removal to remove large solids (like food and trash) that can damage our equipment. Flows are then transported into rectangular settling tanks for primary treatment and removal of suspended solids and fats, oils and grease. Afterwards, the flow goes to our Biological Reactor Basins (BRBs) for nutrient removal. While in the BRBs, flows are added to microorganisms, called activated sludge, for nitrogen removal. The water settles again and then we remove the phosphorous and filter out any remaining solids.
Finally, flows are disinfected using ultraviolet (UV) light.
In the map above, you can see a small portion of the City (the light green area) has a combined sewer system. This century-old system carries combined sewage — a mixture of rainwater and sewage — to four outfalls located throughout Alexandria (noted with red dots on the map). AlexRenew's RiverRenew program was designed to capture and convey these flows to AlexRenew's wastewater plant for treatment. Once complete, RiverRenew will prevent approximately 120 million gallons of combined sewage from entering our waterways each year.
