Minimization Of Excess Sludge Production By Metabolism Uncoupling

Activated sludge process has been widely adapted in wastewater treatment, which also generates a large quantity of excess sludge daily as a byproduct. Furthermore, the ultimate disposal of excess sludge by landfill or incineration may create severe secondary environmental pollution. So how to deal with the excess sludge has become an urgent problem to be solved.In order to solve this problem, an ideal solution may be to minimize the excess sludge production during the wastewater treatment. In light of a newly developed theory of metabolism uncoupling, catabolism could be uncoupled with anabolism under particular conditions, thereby resulting in energy spilling. The dissipated energy can not be available for anabolism so that the sludge growth will be limited. The methods developed from the metabolism uncoupling have been concluded in this paper. In view of the engineering feasibility of these methods, the utilization of reagent provides a promising way to decrease the amount of excess sludge. Two types of reagent were selected, one was inhibitor, and the other was uncoupler.Inhibitor Cu/Zn- and uncoupler 2, 4-dinitrophenol (dNP) -containing short-term batch experiments showed that they both can reduce the sludge yield effectively. But the inverse effect to the effluent of inhibitor was much greater than uncoupler. The inhibitor coefficients were l/K_i,Cu=0.39, l/K_i,Zn=0.13, l/K_i,dNP=0.05 (concentration less than 8 mg/L), 1/K_i,dNP =0.14 (concentration more than 8 mg/L), respectively. The 70-day-operation of SBR with 5 mg/L dNP addition showed that the excess sludge production could be greatly decreased and the effluent was affected slightly.