Total count of microorganisms contaminating water supply system of Ismailia City, Egypt.

The efficiency of water purification in the French and the British systems of Ismailia city was evaluated concerning the contaminating microorganisms. Counting of microbial contaminants was based on the phenotypic characters of the colony type. Colony-types of eubacteria, eumycetes, Micromonospores and Streptomyces enumerated in the crude water and the different steps of purification. Total counts of microflora in both systems were higher than the counts in canal water. Meanwhile, microbial isolates were higher in the French system than that of the British one. The increased counts in tap water, compared with canal water, were recorded in winter for bacteria and in spring for fungi. These data showed variations in the microbial total counts according to: plant system, steps of purification, chlorination season and type of microbes.