METHOD FOR TREATING SLUDGE

摘要

PROBLEM TO BE SOLVED: To provide a method for treating sludge by heating/pressurizing floatation thickening using digestion gas which method uses a pressurizing method using the digestion gas, and a heating method jointly and is an economical thickening method keeping equipment ability un-lowered by taking notice to a bubble generation means by a temperature difference and a heat source obtained in a sewage treatment process. SOLUTION: In this method for treating sludge, previously heated sludge is mixed with water obtained by forcedly dissolving carbon dioxide into sewage secondary effluent and/or wastewater treated water, or the like under a pressurizing condition to stick the bubble generated due to a temperature difference and a pressure difference generated by the mixing to the sludge to float and separate the sludge. By heating with steam the sludge with carbon dioxide dissolved forcedly therein under the pressurizing condition and returned into normal pressure, the bubbles generated from the temperature difference and the pressure difference are stuck to the sludge to float and separate the sludge.