HEATING FLOATATION CONDENSING PROCESS FOR SEWAGE SLUDGE BY CARBON DIOXIDE GAS

PROBLEM TO BE SOLVED: To effectively treat a large amount of biological sludge and/or excess sludge by a comparatively small equipment by introducing carbon dioxide gas dissolved water into biological sludge and/or excess sludge, heating, making foams to be produced adhere to the sludge and carrying out the floating separation. SOLUTION: In a sewage sludge treatment process 10, sludge is introduced into a heating tank 12 and heated, and the sludge is into a heating floatation tank 18. On the other hand, sewage treated water and digestion gas produced from a digestion tank are fed into a melting tank 14, and when the digestion gas is blown into treated water in the melting tank 14, carbon dioxide gas dissolved water is prepared and fed into a storage tank 15, and further fed into the heating floatation tank 18. The sludge is mixed with the carbon dioxide gas dissolved water and brought into contact together to generate foams from the carbon dioxide gas dissolved water, and the foams adhere to the sludge. The sludge is floated gradually by the arrangement, and a sludge layer is formed on the upper section of the heating floatation tank 18. The sludge is separated from a water layer and fed into the digestion tank to carry out the anaerobic digestion.