5.18.13.4 Advantages and DisadvantagesThe advantages and disadvantages of these MBBR processes are as follows:a. Advantagesi. These processes can enhance the activated sludge process by providing a greaterbiomass concentration in the aeration tank and thus offer the potential to reduce the basinsize requirements.ii. Packing materials can maintain the concentration of nitrifying bacteria in the aerobic tank ata high level, and the nitrification reaction proceeds efficiently. Hence, these processes canimprove the volumetric nitrification rates and accomplish the denitrification in aeration tanks byhaving anoxic zones within the biofilm depth.iii. These processes can be used for the upgrading of existing STP, especially when space isan issue.