Environmental Effects of Electrolytically Generated Halogens for Biofouling Control

摘要

The electrolytic generation of biocides from seawater or from brine is a proven, economical and safe method for use in industrial plants. When injected in the cooling water circuits of electric power stations or industrial plants, on-site generated biocide provides efficient protection to the equipment against organic fouling without the undesirable side effects of commercial hypochlorite (such as the build up of hard deposits by reaction of significant excess alkalinity with the substances dissolved in water) or the safety hazards connected with the transportation, storage, homeland security, and handling of chlorine gas. At issue in this paper is the impact of this electrolytic process on the environment. This presentation is the cumulative research work by these two Universities to characterize the oxidants, determine the efficacy of produced biocides to control marine organisms and their re-growth, measure the toxicity of the neutralized water, and analyze the disinfection by-products (DBPs) generated in this process. Results of the studies indicate the major oxidant formed from brine is hypochlorite but small amounts of chlorine dioxide are also formed in the process. Analysis of the electrolyzed seawater indicates that disinfection byproducts are in the form of bromoform and chlorodibromomethane. But all levels measured were below drinking water standards for the DBPs. If the electrolyzed seawater is neutralized or dehalogenated with sulfite, any efficacy and toxicity is eliminated. It is concluded that if seawater electrolytically treated is dehalogenated prior to discharge, environmental effects will be negligible.