| 摘要 |
PROBLEM TO BE SOLVED: To reduce the load on a membrane filtration device for removing Cryptosporidium, to prolong the service life of the membrane material and to eliminate the need of performing heat sterilization treatment prior to dehydration/filtration treatment. SOLUTION: In a drinking water treatment plant, wastewater which is caused in a drinking water treatment system A for treating water from a reception well is transferred from the system A to the system B. In this wastewater treatment system B, the wastewater is concentrated in a concentration device 3 and then the resulting concentrated sludge is subjected to dehydration/filtration treatment with a filter press 14 to discharge dehydrated cake 16 to the outside of the wastewater treatment system B. Also, a membrane filtration means 8 is placed in the wastewater treatment system B and in the initial stage of the dehydration/filtration treatment with the filter press 14, a filtrate resulting from the dehydration/filtration treatment is introduced into a membrane filtration treatment system for passing the filtrate through the membrane filtration means 8, and thereafter, the filtrate is not passed through the membrane filtration means 8 and directly returned to a source water stream 10 in the drinking water treatment system A. |
