Improving Feed Water Recovery and Reducing Backwash Waste In Membrane Filtration Process

This paper presents the recent advancements in the pressurized membrane filtration system, which significantly improves the feed water recovery and reduces backwash liquid waste volume. The membrane filtration system presented in this paper can achieve a feed recovery as high as 99.5%. To achieve such a high recovery, two backwash process strategies and controls are implemented in the new system: 1) filtering down to the backwash level to reduce the liquid holding in the membrane vessel before backwash; and 2) air pushed liquid backwash to minimise filtrate usage during backwash. Both pilot experiments and large scale plants demonstrated that the new backwash process achieved high backwash recoveries without compromising backwash performance.