UPGRADATION OF AN EXISTING ACTIVATED SLUDGE UNIT TREATING DYES WASTE

A study was carried out on an activated sludge unit that was subjected to high fluctuations of flow and inlet C.O.D., to find out the actual capacity of the plant to accommodate increased influent load due to expansion of production activities. Various kinetic parameters were evaluated in actual working conditions, using W.W. Eckenfelder's kinetic model of biochemical oxidation. The biological constants determined in the actual working plant using W.W. Eckenfelder's mathematical model were as under:Reaction rate constant, K = 5.84 d−1, Cell Yield, a = 0.42 mg VSS/mg substrate, Endogenous Co-efficient, b = 0.089 d−1, Oxygen equivalent of the fraction of organic matter removed, a′ = 0.36 mg oxygen/mg substrate removed, Endogenous Decay Rate, b′ = 0.125 d−1, Degradable fraction, kd = 0.523 mg/mg. At some days when inlet COD increased abnormally, the value of K as high as 53 d−1 was observed which revealed highly degradable nature of effluent.On the basis of these parameters the plant was redesigned and it was found that the existing activated sludge unit could receive a load of 150 kg C.O.D./d in addition to the existing load of 270 kg C.O.D./d, without any modification in the plant.