A hollow membrane filter backwash system using gas pressurised at at least two pressures feed from the down stream side to push water through the filter to clean it

摘要

597259 A method of backwashing a membrane filtration system is disclosed. The system has at least one permeable membrane (6), preferably a hollow fibre membrane, the method comprising the step of applying a pressurised gas (19) at a variable pressure to permeate remaining present in the system when filtration process is stopped or suspended to provide liquid for backwashing pores of the permeable membrane during a backwashing process. Also provided are methods of filtering solids from a liquid suspension using alternating liquid backwash pressures.