The objective of the activated sludge process, as with other biological treatment processes, is the removal of organic and select inorganic compounds from wastewaters. With ever-increasing treatment requirements, it will become necessary for treatment facilities to be operated more effectively to meet the stringent effluent quality while continuing to treat varying wastewater flows and contaminant loads. Biological systems should be monitored continuously be analytical measurements, visual observations, and operational tests, and proper responses should be made to maximize the performance of the systems to achieve the required effluent quality.