Hanan Kurabi *¹

¹Food Science Department, Faculty of Agriculture, University of Aleppo, Syria.

(*Corresponding author: Dr Hanan Kurabi. E-Mail:  hanansrn76@gmail.com  ).

Received: 22/ 03/ 2025                 Accepted: 21/ 07/ 2025

Abstract: 

The aim of this study was to evaluate the therapeutic effect of ozone on the microbial and sensory properties of drinking water supplied by several residential units at the University of Aleppo. The study was conducted from June to September 2024 in the Microbiology Laboratory of the Department of Food Sciences, Faculty of Agricultural Engineering, Aleppo. The results showed that 33.33% of the studied water samples complied with the Syrian standard specifications due to their low initial microbial load and the absence of fecal coliform bacteria, E. coli, yeasts, and fungi. However, 66.66% of the samples were unfit for drinking due to their high initial microbial load and fecal contamination resulting from leakage from sewage pipes into drinking water networks or contamination during transportation and packaging operations. The effect of treating the samples with ozone at a concentration of 0.3 g/L for 15 minutes was positive. The ozone treatment reduced the total coliform count in samples (S2, S3, S6, S7, S8, S9) by 4, 16, 4, 14, 33.3, 33%) respectively. As for the fecal bacteria, their count decreased in the previous samples by (100, 5.5, 100, 5, 100, 100)% respectively. Yeasts and fungi were completely eliminated by 100%, which transformed the water samples that did not meet the specifications into samples that met the specifications and were suitable for drinking. Some pathogenic microorganisms transmitted through drinking water were isolated and characterized. A total of 42 intestinal bacterial isolates were isolated, with Escherichia coli accounting for 26%, Pseudomonas aeruginosa accounting for 14%, and Klebsiella accounting for 7%. Treatment with ozone at a concentration of 0.3 g/L for 15 minutes had no effect on the sensory characteristics of the water samples studied.

Keywords: Drinking water, ozone, pathogenic bacteria, microbial quality.

Full paper in Arabic: pdf