Computer Detection of the Impact of Hydraulic Shocks on Plant Performance

Storm and diurnal flows subject activated sludge plants to hydraulic disturbances. Some disturbances originate within a plant as recycle, wasting, or influent pumping rates change. During dry weather flow, the most significant flow variations come from the pumps lifting wastewater into the plant, which causes both high frequency and high amplitude disturbances. Records from a number of plants indicate that pump-induced transients commonly occur. Hydraulic transients degrade effluent quality. Hydraulic dis turbances from influent pumping stations increased the sus pended solids concentration discharged from the final settler.1-2 Research has shown that conventional treatment plants do not greatly attenuate flow transients and that flow variations increase solids transport in secondary settlers.3 This research evaluated the effect of influent and recycle pumping disturbances on final settler efficiency. Particular ques tions were: