BIOLOGICAL TREATMENT OF ORGANIC WASTE SOLUTION

摘要

PROBLEM TO BE SOLVED: To obtain a method for biological treatment of an org. waste soln. performing digestion in high sludge concn. and capable of allowing the discharge amt. of sludge to approach zero by using a small-sized apparatus. SOLUTION: Raw water is introduced into an aeration tank 1 to be biologically treated and a biologically treated soln. 9 is separated by a membrane separator 7 and a permeated soln. is discharged as treated water while a part of a concn. soln. is returned to the aeration tank 1 as a return soln. 3. The other part of the concn. soln. 12 is introduced into an aerobic digestion tank 21 having an immersion type membrane separator 22 as excessive sludge and digested by diffusing air into the concn. soln. from an air diffuser 27. The soln. in the tank is separated by the immersion type membrane separator 22 and a permeated soln. is discharged as treated water. A part 32 of an aerobic digestion soln. is treated with ozone in an ozone treatment tank 31 to modify sludge and this sludge is circulated to the aerobic digestion tank 21.