Sequencing Batch Reactor

Sequencing batch reactors (SBR) or sequential batch reactors are a type of activated sludge process for the treatment of wastewater where in different treatment operations are carried out in a common vessel. Sequencing Batch Reactor reactors treat wastewater such as sewage or output from anaerobic digesters or mechanical biological treatment facilities in batches.

Different types of environments are developed in the vessel by controlling the process equipment such as blower for diffusers, pumps and decanters during a cycle. The treated effluent may be suitable for discharge to surface waters or possibly for use on land.

The entire process occurs in 5 different stages. These are fill, react, settle, decant and idle. Initially, the inlet valve opens and the tank is filled. Then mechanical mixing is carried out in absence of air. Hence, it is called an anoxic stage. Then in the next stage, fixed or floating mechanical pumps or fine bubble diffusers are used to transfer the air to the floor of the tank. Oxygen is bubbled through the mixture of wastewater and activated sludge to reduce the organic matter (measured as biochemical oxygen demand (BOD) and chemical oxygen demand (COD)). This process is known as aeration.

Then in the third stage, the suspended solids are allowed to settle. Finally, during the last stage (fourth) of the sequencing batch reactor process, the outlet valve opens and the clear and treated effluent or supernatant liquor is collected in an adjoining tank.

Most of our clients both private and public companies are switching to sequencing batch reactor technology from the conventional treatment ones because of the growing demand of better quality of effluent and because we assure them about making the design simple and such that it can be operated and maintained easily