Treatment of wastewater containing reducing sulfur compounds by microorganisms

摘要

PURPOSE: To make a process for treating waste water contg. reductive sulfur compounds with sulfur-oxidizing bacteria more highly efficient and to stabilize quality of the treated water by using Pseudomonus genus bacteria having a sulfur-oxidizing function when the pH of a liquid in a biological reaction vessel contg. the bacteria is neutral. CONSTITUTION: In this treatment, activated sludge drawn out from an activated sludge process equipment used for treating municipal sewage, etc., is placed in a biological reaction vessel 3 of another activated sludge process equipment for the objective treatment. Then, waste water consisting essentially of artificial thiosulfuric acid waste liquid, etc., is supplied to the biological reaction vessel 3 so that the hydraulic residence time in the vessel 3 is adjusted to a prescribed value. Further, pH of the liquid in the biological reaction vessel 3 is controlled so as to be a prescribed value by using an alkali solution. Thus, by controlling pH of the liquid in the reaction vessel 3, a bacterium group mainly composed of Pseudomonas genus sulfur-oxidizing bacteria can be acclimatized and grown and waste water is treated by using the Pseudomonas genus sulfur-oxidizing bacteria capable of oxidizing reductive sulfur compounds.