Bahman Behzadi - Ph.D. Candidate, Department of Chemical Engineering, Mahshahr Branch, Islamic Azad University, Mahshahr, Iran
Maziar Noei - Associate Professor, Department of Chemistry, Mahshahr Branch, Islamic Azad University, Mahshahr, Iran
Alireza Azimi - Assistant Professor, Department of Chemical Engineering, Mahshahr Branch, Islamic Azad University, Mahshahr, Iran
Masoume Mirzaei - Assistant Professor, Department of Chemical Engineering, Mahshahr Branch, Islamic Azad University, Mahshahr, Iran
Hossien Anaraki Ardakani - Assistant Professor, Department of Chemistry, Mahshahr Branch, Islamic Azad University, Mahshahr, Iran

Water can contain microorganisms and cause deposition and corrosion in cooling tower systems. Therefore, the water treatment of cooling towers is essential. Various biocides are used to remove bacteria and disinfect the water of cooling towers, and the most commonly used are sodium hypochlorite and chlorine compounds. This work examined two chlorinated water, namely hypochlorous acid and sodium hypochlorite, in two pilot and industrial cooling towers. The results of the experiments on the pilot tower showed that the performance of hypochlorous acid in the disinfection and removal of bacteria and microorganisms was excellent. The total bacterial count decreased from ۱۰۰۰۰ to less than ۸۰۰ (cfu/mL) compared to sodium hypochlorite. The experiments were performed on the industrial cooling tower of an acetic acid unit for six months, in which pH, free chlorine, total bacterial count (TBC), and sulfate-reducing bacteria (SRB) were measured. The very high disinfection power of hypochlorous acid compared to sodium hypochlorite and its relatively lower pH level led to a significant reduction in the use of chemicals in the cooling tower. The experiments and TBC and SRB tests showed outstanding performance in using hypochlorous acid.

Cooling tower, Hypochlorous acid, sodium hypochlorite, TBC and SRB bacteria