Sequencing batch reactors (SBR) are a type of activated sludge process for the treatment of wastewater. They are composed of a single or more “batch” reactors where the wastewater is added, treated to remove undesirable components and then discharged. After passing through screens for grit removal, the liquid influent is sent to the SBR where the mixing and the aeration occur. The treated wastewater is then subject to equalization, filtration and disinfection to be suitable for discharge to surface waters or possibly for use on land. The obtained solids are sent to a thickener and afterwards to an aerobic digester for final disposal or possible reuse. They are extremely suited for wastewater treatment applications characterized by low or intermittent flow conditions. These systems have a relatively small footprint, are particularly flexible in case of changes of the effluent parameters and are even cost-effective.
Same phase sequencing system can be adopted for traditional chemical-physical treatment.