CLEANING METHOD OF SEPARATION MEMBRANE OF MEMBRANE SEPARATION APPARATUS

PROBLEM TO BE SOLVED: To provide a cleaning method of a separation membrane of a membrane separation apparatus which can clean a separation membrane sufficiently.SOLUTION: A cleaning method of a separation membrane 9 of a membrane separation apparatus 6 uses a chemical 36 containing sodium hypochlorite 20 and acid 23 as a chemical for cleaning, compares a transmembrane pressure difference before cleaning and a transmembrane pressure difference after a first cleaning in which the separation membrane 9 is cleaned by using the chemical 36, and changes at least either of effective chlorine concentration of the chemical 36 in subsequent cleaning or the number of times of cleaning based on the comparison.SELECTED DRAWING: Figure 1 【課題】分離膜を十分に洗浄することができる膜分離装置の分離膜の洗浄方法を提供する。【解決手段】膜分離装置６の分離膜９の洗浄方法であって、洗浄用の薬液として、次亜塩素酸ナトリウム２０と酸２３を含む薬液３６を用い、洗浄前の膜間差圧と薬液３６を用いて分離膜９を洗浄した初回洗浄後の膜間差圧とを比較し、この比較に基づいて、その後の洗浄における薬液３６の有効塩素濃度および洗浄回数の少なくともいずれかを変更する。【選択図】図１