Sequencing Batch Reactor (SBR)

SBR is new technology for the treatment of domestic and industrial wastewaters.

The SBR can treat wide range of domestic and industrial wastewaters, at flow ranging from few thousand liters to millions of liters per day.

The SBR process can treat any wastewater that can be treated by activated sludge process including anoxic/oxic systems, aerated lagoons, extended aeration processes, trickling filters, rotating biological contactors (RBCS) and oxidation ditches.

Like other biological effluent treatment processes SBR works by developing mixed culture of bacteria (biomass) which is effective for removal of BOD, COD and nutrients commonly found in wastewater.

The SBR is true batch reactor treatment mode, which does not allow wastewater to enter the reactor during react, settle decant phases.

SBR has unique ability to acts as equalization tank, aeration tank and clarifier within single reactor. For large quantities of wastewater flow (more than 500 cubic meters /day) two or more reactors are utilize in predetermined sequence of operation. Each reactor maintains its own treatment regime and all phases of treatment occur in each reactor. Feathers of SBR can be explain as follows-

  • Tolerate variable hydraulic loads – Mixed liquor suspended solids cannot be washed away by hydraulic surge since effluent withdrawal is typically accomplished in separate phase following termination of flow to each reactor.
  • Tolerate variable organic loads - Each influent (wastewater input) liquid batch is diluted with previous cycle reactor content.
  • Controls filamentous growth – Filamentous microorganisms are control by creating anoxic conditions during fill phase.
  • Provide ideal conditions for settling - Since there is no flow to the reactor during settling and no mechanical sludge collection device "stirring" provided ideal conditions for settling.

Benefits of SBR –

  • It is true reactor treatment system and able to provide consistent effluent quality to desired limits.
  • SBR is designed to minimize operation and maintenance cost all equipments accessible from side the plant eliminating the need to dewater. As –
    • Floating aerators
    • Submersible mixers
    • Effluent pumps
  • Return Activated sludge piping is eliminated.
  • Lower Installation costs- Maximum all operation required in effluent treatment are carried out in a single reactor it eliminates need of separate structure for each unit operation this generally result in to lower construction and installation cost.
  • Lowest electrical operating cost- Electricity consumption per Kg BOD destroyed is around 1.1 KW as compare to other processes (1.7 KW with conventional activated sludge process).


Domestic Applications –
  • Municipal
  • Resorts
  • Institutions
Industrial Applications –
  • Chemical/ Petrochemical
  • Leachate
  • Food
  • Tobacco
  • Paper & Pulp
  • Dairy
  • Textile
  • OCPSF( organic chemicals, plastics ,Synthetics and Fibers)
  • Sugar