Document Type : Research Paper
Authors
1 Ph.D. Candidate, Department of Chemical Engineering, Mahshahr Branch, Islamic Azad University, Mahshahr, Iran
2 Associate Professor, Department of Chemistry, Mahshahr Branch, Islamic Azad University, Mahshahr, Iran
3 Assistant Professor, Department of Chemical Engineering, Mahshahr Branch, Islamic Azad University, Mahshahr, Iran
4 Assistant Professor, Department of Chemistry, Mahshahr Branch, Islamic Azad University, Mahshahr, Iran
Abstract
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 10000 to less than 800 (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.
Highlights
- The disinfection performance of Javelle water and chlorinated water in pilot and industrial cooling towers was evaluated;
- Due to the problems caused by the use of Javelle water, and especially its quality, which is very sensitive to light and heat and decomposes quickly, two substances, namely chlorinated water (hypochlorous acid) and Javelle water (sodium hypochlorite), were examined in pilot and industrial cooling towers;
- The experiments on the pilot tower showed that the performance of chlorinated water in the disinfection and removal of bacteria and microorganisms was excellent, and the total bacterial count (TBC) compared to Javelle water declined from 1000 to less than 800 (cfu/mL);
- The experiments on the industrial cooling tower of an acetic acid unit were also carried out for six months, and pH, free chlorine, and TBC were measured. Moreover, the results of process experiments and TBC tests confirmed the acceptable performance of chlorinated water.
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