Waste treatment and management in chlor-alkali industries

The chlor-alkali industry produces chlorine (Cl2) and caustic soda from brines, by electrolysis of a salt solution. The world’s chlorine capacity at the beginning of 1988 was approximately 42.3 million metric tons per year and the corresponding caustic capacity was approximately 46.1 million metric tons per year. Three main technologies applied for chlor-alkali production are mercury cell, diaphragm cell, and membrane cell process. Each process has a different method for producing chlorine at the anode, and producing caustic soda and hydrogen, directly or indirectly, at the cathode. This chapter describes the manufacturing processes, energy requirement, waste characterization, environmental impacts, pollution prevention and abatement, treatment technologies, costs, monitoring, global overview, and standard requirement of air emission and effluents discharge of the chlor-alkali industry.