Monitoring Fouling of Reverse Osmosis Membranes using Electrical Impedance Spectroscopy
The use of modern high flux reverse osmosis membranes with low salinity feeds at high recovery rates, makes the measurement of fouling by flux decline difficult in practice. Early detection of fouling is important, because the onset of fouling occurs at a critical flux which is difficult to predict a priori.
An alternative method, measuring the electrical properties of the membrane is proposed here. The fouling of a reverse osmosis membrane was measured using an INPHAZE Electrical Impedance Spectroscope from frequencies of 0.01 to 100,000 Hz. Both the conductance and impedance showed dramatic changes when the reverse osmosis was fouled by a small amount of protein and precipitated divalent salts. Such a method has great potential for online measurement of membrane fouling and more effective operation of membrane filtration systems.