Sequencing Batch Reactors

Sequential Batch Reactor (SBR) is a type of activated sludge process which consists of a sequence of steps that are carried out in a single compartmentalized tank. In SBR, the complete biological treatment is divided into cycles with each cycle being of specific duration, during which all treatment steps take place. A basic cycle comprises of the phases such as wastewater filling, aeration, settling and decanting. Fine bubble diffusers are provided in SBR basins to maintain aerobic conditions. Secondary clarifier at the downstream of SBR is not required. Sludge recirculation forms an integral step and the surplus activated sludge is removed to by sludge wasting to sludge sump. After the decanting phase, sludge wasting shall take place. A programmable logic controller (PLC) is generally used to control the sequential nature of the complete process.

Advantages of SBR:

• Fill & draw type of simple operation contained in one tank coupled with high flexibility in operations.
• SBR is efficient not only for the reduction of BOD, COD, TSS, but also for biological nutrient removal (Nitrogen & Phosphorus).
• SBR offers significant reduction in the tank volume and thus is the favored technology when area is the constraint.