Experimental optimization of the disinfection performance of sodium hypochlorite and hypochlorous acid in pilot and industrial cooling towers

Water can contain microorganisms and cause deposition and corrosion in cooling tower systems.Therefore, treatment of thewater of cooling towers is important and essential.Various biocides are used to remove bacteria and disinfect the water of cooling towers,the most commonly used of whichare sodium hypochlorite and chlorine compounds. Two chlorinated water,(hypochlorous acid) and (sodium hypochlorite) were tested in this studyon two pilot and industrial cooling towers.The results of experiments on the pilot tower showed that the performance of hypochlorous acid in disinfection and removal of bacteria and microorganisms has a high capability.The total bacterial count decreased from 10000 (cfu/ml) to less than 800 (cfu/ml) compared to sodium hypochlorite.Experiments and researches were performed on the industrial cooling tower of the Petrochemical Acetic Acid Unit for six months, in which pH, Free Chlorine, TBC and SRB were measured.Very high disinfection power of hypochlorous acid compared to sodium hypochloriteand also low pH of hypochlorous acid compared to sodium hypochlorite led to a significant reduction in the use of chemicals in the cooling tower.The results of Experiments and TBC and SRB tests showed very good performance of using hypochlorous acid