METHOD OF AEROBICALLY TREATING WASTEWATER AND TREATMENT TANK

摘要

A method for treating liquid-waste utilizing carriers having microorganisms immobilized thereon and an aerobic treatment tank used in the method. At least one underwater agitation type aeration apparatus having an air-diffusing mechanism on a discharge side of an impeller is provided in the treatment tank. While supplying atomized air into the liquid-waste, the carriers and the liquid-waste are circulated through the treatment tank by means of the underwater agitation type aeration apparatus, to thereby substantially uniformly distribute the carriers in a floating state in the treatment tank. The discharge opening of the underwater agitation type aeration apparatus is provided in the vicinity of a bottom surface of the treatment tank or at an intermediate position with respect to the depth of liquid in the treatment tank. In the latter case, the underwater agitation type aeration apparatus sucks the carriers and the liquid-waste in the vicinity of the bottom surface of the treatment tank through a draft tube extending from the underwater agitation type aeration apparatus toward the bottom surface of the treatment tank.