The activated sludge process has been discussed in much detail before for its suitability to wastewater treatment. Here in this article I discuss another form of this treatment method, the sequential batch reactor and the advantages it offers.

The sequential batch reactor that is used in wastewater treatment is similar to the activated sludge method. In this reactor the three important steps namely – aeration, wastewater sedimentation and decant process are combined to obtain the optimum performance. These three steps are carried out in a single reactor. The sequential batch reactor design makes use of (two or may be more) tanks laid parallelly. These tanks can either be operated alternately or they can used in a sequence consisting of five steps. These five steps are:

1) filling of the tank,

2) encouraging the reactions in wastewater,

3) allowing the wastewater matter to settle down,

4) drawing the wastewater and the last stage which is the

5) idle state.

Since the reactor can be operated in batches, it can be used as a viable model that can be applied for the biological treatment of wastewater released by industries. The batch wise operation also makes it possible to handle the industrial wastewater that can vary significantly in its characteristics and in its volume from time to time.

Thus the major advantages achieved when using the sequential batch reactor are as follows:

1) It maintains a consistent quality of the effluent which is possible due to the tranquil batch settling method.

2) It is suitable for use with low volume inflow in wastewater treatment plants where the flow level varies widely.

3) It allows flexible operational levels that allows you to control and filter out nutrients from the wastewater.

4) It is less operator attention intensive when compared with some of the mechanical treatment methods.

5) It is a simple method of treatment and also reliable at the same time.

However there are some disadvantages that cannot be overlooked:

1) Though it requires less attention, it needs a skilled operator.

2) The reactor needs regular maintenance and should be inspected periodically.

3) Some users have faced problems during the decant process.