INHIBITION OR ELIMINATION OF MOLD BULKING IN ACTIVE SLUDGE PROCESS FOR WASTE WATER

摘要

PURPOSE:To inhibit or eliminate mold bulking without effecting active sludge in an aerobic active sludge process by adding iodine into waste water containing the active sludge. CONSTITUTION:Waste water is charged from a tank 5 into an aerating vessel 1, and agitated along with direction shown by an arrow by the injection of air from a sparger pipe 8. Sludge in the vessel 1 flows through a lower space below a partition plate 3 into a sedimentation vessel 2 owing to a level difference caused by the charge of the waste water. An upper portion in the vessel 1 constitutes a supernatant. Part of precipitated sludge is reused for contact with the waste water. In this process, iodine is added in the borm of a simple substance or its solution into the waste water containing the active sludge in the vessel 1. The solution is an aqueous halide solution containing dissolved I2 esp. an aqueous KI solution, or a solution containing an organic solvent such as alcohol, ether or the like. The solution is preferably an I2 solution of a solvent having a low volatility and an ability to borm a compound of I2 with the solvent, because of the necessity of retaining I2 for a long time in the waste water under a sublimating condition.