Effect of carriers and micro-animals on the purification ability of Johkasou systems

摘要

Domestic wastewater is the major factor responsible for the pollution load in public water areas in Japan. Johkasous are important pieces of equipment for controlling the purification of domestic wastewater, and are biological treatments which make use of the metabolism of microorganisms such as bacteria and micro-animals to decompose the organic matter in wastewater. It is therefore important to have functional microorganisms inhabiting the carrier at a high density to accelerate the effectiveness of the bioreactor. The purpose of this study is to examine the relationship between micro-animals adhering to the carrier and the purification performance of Johkasou systems. Result of this study, the bdelloid rotifer of the genus Philodina was specified for a micro-animal that contributed to improvement of the transparency of treated water. And, became clear that it is effective using the sponge carrier to attach the bdelloid rotife Philodina in high density into the aerobic chamber of Johokasou. Moreover, it was confirmed that the advanced removal of BOD and the almost complete nitrification of ammonium nitrogen can be achieved by using the sponge carrier respectively. Up to now, in the development of Johkasou systems, had not been examined about the methods of effective use of the functional micro-animals. It was suggested that Philodina sp. is an index micro-animal for improving the clarification of wastewater, and it is necessary to design the carrier that can be attaching functional micro-animals such as bdelloid rotifers in high density for development of Johkasou systems in future.