Sequencing Batch Reactors Information

Sequencing batch reactors are fill-and-draw activated sludge systems for wastewater treatment. Wastewater is added to a single "batch" reactor, treated to remove undesirable components, and then discharged. A sequencing batch reactor (SBR) system is well-suited for wastewater treatment applications characterized by low or intermittent flow conditions. A sequencing batch reactor or SBR can be used to treat both municipal and industrial wastewater. Using a single batch reactor, equalization, aeration, and clarification can be achieved in wastewater removal processes.


Sequencing batch reactors are used with wastewater treatment methods that use activated sludge system, which operates sequentially in time rather than in space, so that all steps of the process take place one after the other in the same tank instead of moving to a second tank for continuing treatment. A key element of processes involving sequencing batch reactors is that a tank is never completely emptied, but rather a portion of settled solids is left in the tank for the next cycle. The retention of sludge within the tank establishes a population of microorganisms uniquely suited for treating the waste. A sequential batch reactor provides full biological treatment of crude sewage in normal domestic environments where there is no public sewer and where a septic tank is not environmentally acceptable. Biological wastewater treatment uses aerobic or anaerobic microorganisms in sequencing batch reactors to achieve decanted effluents and to separate sludge containing microbial mass and pollutants.

Special Software Programs

Special software programs have been developed to work with sequencing batch reactors in order to control sequencing program arrival and sequencing program departure. These types of programs can operate the process sequence in a viable manner to keep the biological treatment performance optimum while managing all flow variations. These programs can control the operation of all motorized equipment of the sequencing batch reactors system and manage a complete series of alarms necessary to maintain good performance of the biological treatment regardless of flow variations throughout the day and evening, attendance of an operator, or any equipment failure including temporary power failure.