Membrane-Based Separations For Low-Effluent Concepts, 1996 Minimum Effluent Mills Symposium Proceedings

Peter H. Pfromm

Institute of Paper Science and Technology

Selective purging of materials such as chloride, metal ions, and hazardous air pollutants is vital for low-effluent mill strategies. Membrane separation processes such as electrodialysis, bipolar electrodialysis, vapor permeation, and pervaporation will be discussed as possible methods. Electrodialysis is a continuous separation process to remove ions from aqueous streams. Industrial applications include demineralization in the food industry, drinking water purification, effluent treatment for metal plating, and boiler water pretreatment. A recently commercialized technique is bipolar electrodialysis. Removal of chloride and potassium from liquors and control of inorganics for low-effluent white water cycles are being investigated at IPST. Emissions in the form of vapors and gases will have to be dealt with for true low emission mill operation. Separation of low molecular weight organics from aqueous or gaseous mixtures can be achieved with high selectivity by membrane permeation. The process is continuous and no spent adsorbents need to be dealt with. This technology is the subject of a joint project at IPST and Georgia Tech.