MICROBIAL QUALITY OF TREATED WASTEWATER USED FORIRRIGATION OF PUBLIC PARKS IN DUBAI, UNITED ARABEMIRATESM.A. KHAN, R. DGHAIM, H. R. BAKSH AND S.M. FAHEEM
This study is aimed at investigating the microbial quality of the treated wastewater used for irrigation of public parks in the emirate of Dubai, UAE. In particular, the presence of selected water quality indicator microorganisms protozoan parasites Cryptosporidium, Giardia and bacteria including Legionella, Pseudomonas, and traditional fecal pollution indicator microorganisms such as total fecal coliform, total coliform and heterotrophic bacteria were studied. A total of 96 samples of treated wastewater (TWW) and irrigated soils from four public parks were collected and tested for Legionella, Salmonella, and traditional bacterial indicators using membrane filtration method. Immunofluorescence assay detected Cryptosporidium oocyst and Giardia cysts. A majority of the tested water samples were found contaminated with Legionella, Pseudomonas, and traditional bacterial indicators. Both Cryptosporidium oocysts and Giardia cysts were detected in these samples with a higher occurrence of Cryptosporidium oocysts (96%) than Giardia cysts (35%). Thefecal coliform bacteria were detected in 60.8% of water samples and 58% of soil samples. Total coliforms were detected in most of the water and soil samples with a higher occurrence than the fecal coliform bacteria. The results of this study indicate that microorganisms are surviving the chlorination used for disinfecting wastewater, and are further multiplying in the public parks irrigation network system. Therefore, monitoring the treated wastewater for bacterial pathogens, protozoan parasites and controlling their growth at the point of end use are vital to reducing the risk of environmental contamination with microbial pathogens.
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