Use of electrolytic processes applied as an alternative treatment to chlorine in water pretreatment in reverse osmosis system

Abstract

Reverse osmosis filtration is one of the water treatments used by industry because it is very effective in removing dissolved salts from water since it uses a specific type of thin, semi permeable membrane. These membranes have characteristically small pores to allow the passage of pure water and reject larger molecules, such as ions and other tiny impurities like bacteria and viruses. Several precautions need to be considered in water treatment before starting the filtration process in the equipment. These precautions are necessary to avoid premature loss of the membranes in the reverse osmosis system equipment. One of the most common problems that cause this damage is the oxidation reaction of the polyamide layer by the chlorine-based disinfectant, which corrodes this layer, substantially decreasing its filtration properties. The objective of this study, therefore, was to verify the possibility of substituting the use of chlorine in water treatment, for the removal of microorganisms, by the passage of an electric current, reducing the probability of biofilm formation and membrane perforation. The methodology consisted of experimental research, to verify the efficiency of the electric current as a biocide in a sample of raw water with cultivated microorganisms. An electrical load of 24 volts was applied, varying the exposure time, using Copper and Stainless Steel 304 as electrodes. The final results showed that in the treatment with the copper electrode and 30-minute retention of the water the results were satisfactory, and the treatment, therefore, could be used in conjunction with other biocides or in isolation reaching up to 103 CFU/ml of Aerobic Bacteria in the feed water.