What is the main operating principle behind a sequencing batch reactor (SBR) used for leachate treatment?

The main operating principle behind a sequencing batch reactor (SBR) used for leachate treatment is to perform all the steps of wastewater treatment – equalization, aeration, sedimentation, and decanting – in a single tank in a sequential, timed manner. Unlike continuous flow systems, SBRs operate in a fill-and-draw mode. The process starts with filling the reactor with leachate. Next, aeration is provided to encourage biological activity by microorganisms, which consume organic pollutants in the leachate. After aeration, the solids are allowed to settle, separating them from the treated liquid. Finally, the clear, treated effluent is decanted (drawn off) from the top of the tank. The cycle repeats with the next batch of leachate. This batch process allows for flexibility in adjusting treatment parameters (e.g., aeration time, settling time) to accommodate variations in leachate composition. The sequential nature and ability to control treatment parameters within a single reactor make SBRs effective for treating the complex and variable nature of landfill leachate.