Schreiber’s continuously sequencing reactor (CSR) is a biological nutrient removal system that sequences through aerobic, anoxic and anaerobic phases in a single basin. The unique design allows complete separation of aeration and mixing with 100% aeration turndown capability, allowing the aeration to be turned off while the CSR applies low-energy mixing without adding air. With Schreiber FlexControls, the CSR process can meet the most stringent of requirements.