METHOD OF TREATING UNCERTAIN WATER IN SEPARATED SEWER SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a method of treating uncertain water and rain water in a separated sewer system by which the quantity of sludge in effluent in the rainy weather is remarkably reduced and the injection rate of disinfectant is decreased. SOLUTION: An upward flow type high speed filter vessel 10 in which floating filter media having apparent specific gravity of 0.1-0.4 is filled is formed by partitioning or replacing a part of a first settling tank in a separated sewage treatment plant. The effluent in clear weather is normally treated by passing through a post stage reaction vessel 2 and a final settling tank 3 and the uncertain water (rain water or ground water) flowing-in, in the rainy weather and exceeding the designed quantity is treated in the high speed filter vessel to remove contaminant or SS and discharged without passing through the reaction vessel 2 and the final settling tank 3.