Sequencing Batch Reactor versus Continuous Flow Process for Pilot Plant Research on Activated Sludge

The objective of this article is to compare the advantages and disadvantages of the sequencing batch reactor (SBR) versus the more conventional continuous flow reactor (CFR) setup for pilot plant studies. The SBR process can offer many superior features for research applications. The control of operational conditions is more reliable, precise and versatile. Data collection by sampling and on-line sensors is made easier, and results are more representative. Kinetic and settling tests that need to be conducted in a separate bench-scale reactor for a CFR can be carried out directly within an SBR pilot plant. Even routine data contains more information than obtained from a CFR, since each SBR cycle is equivalent to a batch treatment experiment. The drawbacks of an SBR pilot plant mainly concern the transferability of certain kinetic and settling results to (full scale) completely mixed flow-through reactors, and some experimental limitations due to the cyclic operation. It is expected that this comparison will support the decision of research teams intending to design a wastewater treatment pilot plant. If an SBR process is selected, some specific design recommendations are given at the end of this paper to make sure that its potential advantages are realized.