ORGANIC WASTEWATER TREATMENT

摘要

PURPOSE:To make a pH adjusting chemical unnecessary by controlling supply of oxygen-enriched gas and/or concentration of oxygen so as to restrict pH of a wastewater to be treated biologically to a prescribed value with carbon dioxide gas generated by oxidation-decomposition of organics in the wastewater. CONSTITUTION:Wastewater 1 is introduced into a reaction tub 2, organics in the wastewater are oxidized into mainly CO2 and H2O and then the wastewater is separated to yeast and treated water 6 by a solid-liquid separation process 5. The pH in the reaction tub 2 is controlled to be <=5.5 since optimum pH for yeast growth is in a low pH region and propagation of microbes besides yeast can be suppressed at the pH. Control of pH is carried out by controlling the supply of oxygen enriched gas 4 and/or oxygen concentration. By this method, a pH controlling chemical is not needed and a pH adjustment apparatus and chemical consumption can be eliminated and thus economical wastewater treatment using yeast is achieved.