Using Ozone and Ultrasound to Reduce RO Membrane Fouling

Abstract
A study was undertaken to assess the usefulness of ozone and ultrasound in reducing the potential of humic acids to foul reverse osmosis membranes. Ozonation alone increased the filterability of low concentrations of humic acids, but the application of ultrasound during ozonation was detrimental, probably because the sound waves reduced the average particle size of colloidal and suspended solids in the solution. The presence of colloidal silica in the humic acid solutions further reduced the fouling potential through the formation of a porous prefilter on the surface of the simulant RO membrane.