| 摘要 |
PROBLEM TO BE SOLVED: To enhance the separation efficiency of silica by inputting trivalent metal compounds into the treated water obtained by decomposing wastewater containing silica in a biological reactor, subsequently concentrating/filtrating it in a ultrafiltration device and treating the concentrated liquid thus obtained in a flocculating/settling tank to separate silica. SOLUTION: Flotages and the like in the wastewater received in a wastewater tank 1 are filtrated in a filtration tank 2 and BOD, COD, SS, oil content, etc., in the wastewater are decomposed by microbes in the biological reactor 3. The wastewater discharged from the reactor 3 is sent to the ultrafiltration device(UF device) 4 as primary treated water. Secondary treated water is obtained by filtration in the UF device 4 and the liquid concentration in the UF device 4 is sent to the flocculating/settling tank 5. The secondary treated water is sent to a reverse osmosis apparatus(RO apparatus) 6 being the final stage to remove silica. A chemical consisting of trivalent metal compounds such as polychlorinated aluminum is supplied into the secondary treated water in a stage previous to the RO apparatus 6 to remove silica by forced precipitation.
|
