METHOD FOR TREATING ORGANIC WASTE WATER

摘要

PROBLEM TO BE SOLVED: To provide a method for treating organic waste water where: a membrane separation unit including a sheet-like membrane in a treatment tank storing a microorganism-containing liquid injected with the organic waste water is immersed; a membrane filtration step to obtain filtered water by performing a membrane filtration treatment with the sheet-like membrane is included; and serious membrane contamination can be suppressed even in a high flux.SOLUTION: A method for treating organic waste water comprises: a first membrane cleaning step to hold a predetermined time in a state of stopping the injection of a first chemical solution and a sheet-like membrane treatment after the first chemical solution containing one or more medicines selected from the group consisting of an acid, an alkali and an oxidizer is injected to the filtered water flow passage side of a sheet-like membrane; and a second membrane cleaning step to hold a predetermined time longer than a time in the first membrane cleaning step in a state of stopping the injection of a second chemical solution and a sheet-like membrane treatment after the second chemical solution containing the same kind of the medicines as the first chemical solution in a higher concentration is injected to the filtered water flow passage side of the sheet-like membrane. The second membrane cleaning step is performed after a membrane filtration step and the first membrane cleaning step are alternately performed a plurality of times.