Anaerobic Baffled Reactors (ABR) are widely used in wastewater treatment plant in order to remove heavy sediment solids so that the carryover wastewater will have lower COD level before going to next step of processes. A typical construction of the tank or reactor usually comprises of different compartments with various outlet levels and it can also be described as having made-up of series of arranged baffles plates so that heavy settleable solids have no chance of escaping.
As illustrated in the above diagram, what you can see is that incoming wastewater is usually diverted to the tank from an elevated pipeline preferably using only gravitational force so as not to create unnecessary turbulence inside the reactor. As wastewater starts to buildup and increase in level, the carryover water will start to overflow to the next compartment leaving heavy solids behind to settle at tank bottom. Usually this method is effective especially for household discharge and agriculture wastewater whereby high amount of heavy solids can be expected.
One of the advantages of using this system is that it generally requires low level of maintenance because basically there are no mechanical moving parts and the baffles position is already fixed without needing further adjustment. Unlike aerobic treatment system, overall setup does not need a lot of attention and intervention. However, the only time when one needs to attend to the baffled reactor is when sludge accumulation starts to increase and eventually lead to carryover to the corresponding compartment. Therefore, depending on the size of the anaerobic baffled tank and reactors and also quality of incoming wastewater, it is best that an auto desludging system should be put in place and set it to run weekly to prevent waste buildup to spill over to another section.
Another major advantage of using anaerobic baffled reactor is that energy usage and consumption will be at minimal level and the only requirement is on the electricity to drive the pump to transfer wastewater to a higher level elevated tank which then feeds by gravitational force going to the reactor. If properly managed and taken care of, the system will offer an energy efficient setup that requires minimal attention and yet contribute close to 70% COD removal.
Related topic: Clarifier/Sedimentation Tank