Nanofiltration membranes reject low molecular weight organic solutes and pass salts either partially or completely. A range of nanofiltration membranes which are stable over a wide pH range (pH 0 to 14), stable at a high temperature (80°C) and resistant to many solvents has been developed. These membranes can be applied to resource recovery within an industrial process stream, or for the treatment and recycling of industrial effluents. Such membrane separation systems have many years of proven performance in large scale industrial applications. These include the treatment of aqueous streams from the chemical synthesis industry, the treatment of acidic and basic streams, including pulp and paper streams, the treatment of pharmaceutical processing streams and the treatment of spent paint sludges.