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Abstract
The adequate supply of safe drinking water is one of the major prerequisites for a healthy life. In developing and emerging nations according to the United Nations Environment Program (UNEP, 2001), eighty percent of the diseases in the developing world are caused by contaminated water. In this research, water quality and microbial contamination from 18 drinking water municipal, non-government managed treatment plants in 3 locations at Giza governorate were investigated. The average total count of bacteria and fungi detected after 4 stages of treatments in these plants was 36.1 cfu/1ml and 232.9 cfu/100ml for bacteria and fungi compared to 2329.9 cfu/ml and 1562.9 cfu/100 ml, with a reduction percentage of the count reaching 98.45 and 85.1, respectively. Although the relative high removal of microbial contamination from the water sources used by these plants, however, several bacterial pathogens were identified in the produced water prepared for drinking including Enterococcus faecalis, E. coli, Enterococcus faecalis, Pseudomonas aeruginosa and Shigella species. The most frequent fungi after treatment were Aspergillus flavus, A. fumigatus, A. niger, A. ustus, Candida spp, Fusarium spp, Penicillium, Rhisopus nigricans and Trichoderma viride. After 3 days of incubation of the produced water, the amount of bacterial endotoxins ranged from 76.8-136.8 ng/ml compared to 621.3-1260.2 ng/ml for water from the original source and from 1.9-2.5 ng/ml for fungal aflatoxins in the produced water compared to 3.2-11.9 ng/ml for the original water sources. In in vitro experiments, the application of ozone gas at 2 ppm induced complete elimination of bacteria and fungi from water after 180 and 240 seconds, respectively. The main diseases reported from patients attending different clinics and hospitals during summer 2014 at the locations using drinking water from these plants indicated that diarrheas and gastroenteritis due to E. coli and Campylobacter jejuni constituted 65.7% of the total patients followed by bacillary dysentery or shigellosis due to Shigella spp. (7.9%) and cholera due to Vibrio cholera (7.2%).