الفهرس 
INTRODUCTION and AIM of the present workOnly 14 pages are availabe for public view
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Abstract
Water quality assessment of drinking water has been studied in Zagazig city, El-Sharkia Governorate, Egypt between Summer 2015 to Autumn 2016. Water samples were collected from 7 sites during the four seasons. These sites are raw water (Bahr Mowees), Prechlorinated Water and Postchlorinated Water from Zagazig drinking water treatment plant and 4 drinking water sites which are (Zuhur District, Zagazig university Area, El-Janine street Area, Farouk Street Area).
Some physical parameters such as: temperature, pH, turbidity, electric conductivity, total dissolved salts, and chemical parameters such as chlorides, alkalinity, total hardness, magnesium hardness, calcium hardness and residual chlorine had been detected. The previous physical and chemical parameters agreed with the standard limits for drinking water in Egypt except alkalinity and residual chlorine.
All water samples in Zagazig city were analyzed for determining the water quality. The bacterial isolates were identified such as: T.V.B, T.C.F, F.C.F, Staph. spp., Salmonella spp., Shigella spp., Pseudomonas spp.and Enterobacteriaceae group on different selective media.
In this study 324 isolates were isolated from all sites and purified.These isolates were tested for gram reaction. The isolates were tested for proteolytic activity which was the ability
of identified isolates to produce protease enzyme. The isolates were detected for blood heamolytic activity.
The most potent 6 bacterial isolates for proteolytic and blood heamolytic tests were confirmed by 16srRNA gene sequencing were Bacillus cereus ATCC 14579 (97%), Aeromonas fluvialis LMG 24681 (95%), Lysinibacillus fusiformis NBRC 15717 (97%), Bacillus aerius 24 K (95%), Lysinibacillus fusiformis NBRC 15717 (96%), Lysinibacillus fusiformis NBRC 15717 (96%).
By studying the effect of different thermal temperature, the effect of pH, the effect of different storage period, the growth of Bacillus cereus gradually decrease.