Sequence Batch Reactor
SBRs are wastewater treatment reactors based on an activated sludge process where all the different stages of nitrification/denitrification, settling and separation take place in the same reactor but dislocated in time. The treatment consists of a cycle of five stages: fill, react, settle, draw and idle. The reactor containing active biomass is first charged with influent, closed and than aerated to satisfy the oxygen demand of the wastewater. During this phase, bacteria oxidize the organic matter as in activated sludge systems. Then, aeration is finally stopped to allow sludge settling.