Pilot plant studies on the removal of trihalomethanes by composite reverseosmosis membranes

The effect of single trihalomethane (THM) (CHCl3) content in various types of water on the performance of two types of reverse osmosis composite membr anes (the AFC99 membrane in tubular module Bl, PCI, and the FT30 membrane i n a spiral-wound element BW3040, FilmTec) have been investigated. The perfo rmance of these membranes in RO tests carried out using distilled water, ta p water and brackish water (1000-5000 ppm. NaCl) with the addition of THM h ave been evaluated in terms of permeate flux and the rejection of dissolved solids and THM. The FT30 membrane provided THM rejection better than 99.5% during the reverse osmosis treatment of tap water and brackish water. The AFC99 membrane exhibited only 80% retention of THM, obtained for the transm embrane pressures in the range of 10 to 30 bars. It was found that the pres ence of CHCl3 slightly affects the transport and separation properties of t he composite membranes used.