ABSTRACT
As indicated in Table 1.2, activated sludge is an aerobic suspended growth process in which microorganisms are grown in a variety of bioreactor configurations for the purpose of removing soluble organic matter. It is a flexible, reliable process capable of producing a high quality effluent. Soluble organic matter is reduced to low levels, and a clear effluent low in suspended solids is produced due to the flocculent nature of the biomass. High degrees of nitrification and of stabilization of insoluble organic matter can also be achieved by operation at a sufficiently long solids retention time (SRT). The process is highly controllable, and its operation can be adjusted in response to a wide range of conditions. It is also relatively resistant to short-term organic and hydraulic loading variations. Its main disadvantage is a result of its controllability; its operation is relatively complicated and requires the attention of qualified and experienced operators. Its dynamic response to transient loading variations can be sluggish, and the capability to respond to such variations must be built into the process. Capital and operating costs, although reasonable, are still significant. In short, successful implementation of an activated sludge system requires the commitment of sufficient capital, operating, and personnel resources to achieve success.
