The Alexandria Sanitation Authority maintains an advanced waste treatment facility that has a capacity of more than 50 million gallons of water per day. It operates a 30-acre facility that provides sewage treatment for over 350,000 residents in an area of nearly 50 square miles. The authority owns and operates various pump stations and interceptor sewers. The Alexandria Sanitation Authority conducts preliminary, primary and secondary treatments and chemical addition for phosphorus removal, sedimentation, filtration and ultraviolet disinfection. Its solid processing methods include gravity thickening of primary and tertiary sludges, centrifuge dewatering, prepasteurization, anaerobic digestion and land application. The authority supports a pretreatment program that prevents the introduction of pollutants and interference with the aquatic life of the receiving waters and biosolids. The Alexandria Sanitation Authority is located in Alexandria, Va.