Aerobic Sludge Digestion

Aerobic sludge digestion is similar to the activated-sludge process. It involves the direct oxidation of biodegradable matter and microbial cellular material in open tanks for an extended period of time. Aeration occurs either naturally or by means of mechanical aerators and diffusers (Figure 3).

                                              Figure 3: Typical Aerobic Sludge Digestion

This process is preferably used only for the treatment of waste activated sludge, a mixture of waste activated or trickling filter sludge with primary sludge, or waste sludge from extended aeration plants or activated-sludge treatment plants designed without primary settling. As compared to anaerobic processes, aerobic digestion affords both advantages and disadvantages (Table 1).

                            Table 1: Advantages and Disadvantages of Aerobic Sludge Digestion