Experimental Study On Effect Of Sludge Reduction By Ferrate

Municipal wastewater is commonly treated by activated sludge process. With the increase of urban scale and wastewater flowrate, this process will generate an increasing amount of excess activated sludge. The traditional sludge treatment and disposal has become international pressing problems because of its large amount, expensive treatment cost and secondary pollution. To resolve the problem, a novel sludge reduction process based by microbial cryptic growth theory has aroused extensive concern. Ferrate (â…¥) is considered as an environment friendly agent for water and wastewater treatment. It has novel properties of oxidation, adsorption, flocculation, coagulation, disinfection and deodorization. The nature of the domestic and international research status and development about sludge reduction technology are summarized in this article. Applying ferrate salt to sludge reduction technology is proposed in this paper. The feasibility and mechanism are tested and researched by experiments. The main research content can be concluded from the paper as follows:Through comparing and analyzing the ferrate preparation and analysis approach, this paper applies and optimizes the electrolytic method of preparation of ferrate, 1500mg/L (for Fe) ferrate was prepared in the laboratory; a method based on spectrophotometry of measuring ferrate concentration was applied.Through the static experiment, the variation laws of concentration of MLVSS, SCOD, nitrogen, phosphorus and polysaccharides in the process of sludge disruption under different ferrate dosage has been discussed systematically in this paper; analysis the impact of different initial pH on sludge disruption effectiveness. The optimum condition and dosage of ferrate were reached.In the experiment, the improved active sludge process A/O process was used as sewage treatment process and the soybean wastewater as test water. A small-scale experimental equipment of activate sludge process-ferrate sludge reduction was designed and manufactured. On the theoretical analysis of sludge reduction process, the design parameters of sludge zero discharge technology was determined. The good effects of sludge reduction were obtained during the operation in the experimental stage. The effluent water quality was not changed obviously and the operating efficacy of the whole system was relatively ideal.