What About On-site NaOCl Generation?

This month's question concerns the feasibility of generating sodium hypochlorite (NaOCl) at a remote well site; specifically, what the required concentrations of feed solutions are, the life of the generated product, and any disposal issues. On-site sodium hypochlorite generation (SHG) systems are premanufactured and can be purchased as a skid-mounted package or assembled at the facility. The process is discussed, along with the components and how the system is sized. Key factors to consider are the purity of the salt and the water hardness, and the cell-cleaning requirements. The water softener recharge waste, residual acid waste from the cell cleaning, and any waste generated from tank cleaning are discussed as the disposal issues. The proper storage tank requirements are given, and criteria is listed for consideration when determining which method is better suited to your needs: the on-site generation of sodium hypochlorite or calcium hypochlorite, or purchasing bulk NaOCl. © 2001 American Water Works Association.