An Integrity Sensor for assessing the performance of low pressure membrane modules in the water industry

There is a need for a low cost, sensitive, on-line sensor to assess the integrity of membrane modules used in the water industry for water treatment, membrane bioreactors and for pre-treatment prior to using nanofiltration or reverse osmosis. A sensor addressing this need is described whose operating principle is based on measuring the differential pressure across a membrane that intercepts a portion of the permeate from the pre-treatment module(s) relative to the differential pressure across a valve. The latter can be adjusted to maximize the sensitivity of the instrument. A dimensionless metric based on the differential pressures is defined and corroborated with the Silt Density Index. The sensitivity of this Integrity Sensor is demonstrated by its response to cutting one fiber in a UF pre-treatment module that contains 1500 hollow fibers.

Research highlights
► Improved Integrity Sensor provides on-line, sensitive, low-cost instrument to assess membrane pre-filtration module failure.
► Improved Integrity Sensor permits adjustment to maintain high sensitivity and backwashing to remove fouling deposits.
► Defined new performance metric for Integrity Sensor that provides a measure of the relative degree of fouling.
► New metric for Integrity Sensor corroborates well with the Silt Density Index.
► Integrity Sensor has sensitivity to rapidly detect breakage of one hollow fiber in a 1500-fiber bundle.