Spiral wound membrane element, spiral wound membrane module and treatment system employing the same as well as running method and washing method therefor

摘要

A spiral wound membrane module (100) comprises a spiral wound membrane element (1) including a separation membrane having high back pressure strength. In filtration running, raw water introduced from a raw water inlet (13) of a pressure vessel (10) is subjected to dead end filtration, and permeate is taken out from a permeate outlet (14). In washing, wash water containing a chemical having a contaminant separating function is introduced from an end of a water collection pipe (5) through the permeate outlet (14) for performing back wash reverse filtration with a back pressure of 0.05 to 0.3MPa. The filtration running is temporarily stopped for maintaining the pressure vessel in a state sealed with the raw water and the permeate for a prescribed time. Thus, contaminants adhering to the membrane surface of the spiral wound membrane element (1) are separated. A treatment system is formed by connecting units comprising spiral wound membrane modules (100) in parallel with each other. In the treatment system, one of the units is subjected to filtration running when another one of the units is washed. In washing, back wash reverse filtration and chemical soaking are performed.