Abstract
Phosphorus removal and collection from domestic wastewater will make a great contribution to conservation of water environment and saving phosphorus as a valuable resource. Iron electrolytic method, one of the practicalized phosphorus removal technologies, brings about increment in electrical consumption. In this study, energy-saving operation was examined on a small-scale anaerobic-oxic domestic wastewater treatment “Johkaso” system with iron electrolytic method. The obtained results were as follows. The increment in electrical consumption by introduction of the iron electrolytic system could be offset by turning off the blower for aeration in the oxic tank during the hours when there might be almost no wastewater inflow; 4 hours per day. Besides, further development for reduction of electrical consumption would be achieved by control of operation of the phosphorus removal device and the number of working blowers. From the point of wastewater treatment performance, there was little observed bad influence to the suspension of aeration in the oxic tank on the removal of phosphorus and BOD. In contrast, there observed slight decrease in both the nitrification activity and the nitrogen removal efficiency especially in winter. Further it may be required for the development of such as shortening of acclimation of the sludge in the treatment system.
