Microbiological quality of drinking water at eight water treatment plants.

Eight drinking water treatment plants were sampled monthly during one year to evaluate the removal of bacterial indicators, new indicators and some pathogenic bacteria. Six plants are allocated along the Nile River at Cairo segment and the two others on Ismailia Canal. In this study many parameters were determined; the classical bacterial indicators (total bacterial counts at 22 and 37 degrees C, total coliforms, faecal coliforms and faecal streptococci) show the same trend in all plant intakes except faecal streptococci parameter. The numbers of faecal streptococci in plant intakes on the main stream of Nile River ranged from 8 to 250 MPN/100 ml, but the others ranged from 80 to 2700 MPN/100 ml. With regard to new indicators; total yeasts, Candida albicans, Aeromonas hydrophlia and total staphylococci ranged from 10(1) to 10(5), 10(2) to 10(5), 10(2) to 10(5) and 10(2) to 10(3) cfu/100 ml, respectively. In case of pathogens, salmonellae ranged between 10(2) and 10(3) cfu/100 ml, total vibrios varied between 10(2) and 10(4) and the Listeria group ranged from 10(2) to 10(5) cfu/100 ml from the intake samples. All tested samples from the outlet of water treatment plants, which produce drinking water, were free of classical bacterial indicators. So the produced water has a good quality from the bacteriological point, according to national and international regulations. On the other hand, the drinking water from some tested plants had one or more positive parameters of new indicators and pathogenic bacteria.

Microbiological profile of raw Nile water.

With the increase of population on the Nile banks, a remarkable increase in industrial, agricultural, human activities, and recreational activities have also occurred. The effluents of such activities are discharged directly into the Nile or through some agricultural drains which finally discharge their wastes into the Nile. Thus, the microbiological monitoring is one of the main objectives to protect the river Nile. This study was conducted to determine the microbiological profile of river Nile at Cairo segment. Eight sites were chosen along the distance (60 Km) from El-Shobak to El-Kanater and tested for two successive years (summer 1994-spring 1996). To achieve this goal, microbiological parameters (total bacterial counts at both 22 degrees C and 37 degrees C, total coliforms, faecal coliforms, faecal streptococci, total yeasts, Candida albicans, Aeromonas hydrophila, salmonellae, total staphylococci, total vibrios and Listeria group) were evaluated. The results showed that the count of the previous parameters ranged between 1.0x10(3)-7.8x10(5) CFU/ml, 5.0x10(2)-6.4x10(5) CFU/ml, 4.9x10-1.6x10(4) MPN/100 ml, 2.0-5.2x0(3) MPN/100 ml, 2.0x10-1.4x10(3) MPN/100 ml, 1.7x10(3)-2.6x10(5) CFU/100 ml, 1.5x10(2)-1.7x10(5) CFU/100 ml, 1.0x10(3)-2.4x10(5) CFU/100 ml, 1.3x10(2)-5.1x10(3) CFU/100 ml, 1.0x10(2)-3.3x10(3) CFU/100 ml, 1.0x10(2)-3.8x10(4) CFU/100 ml and 1.0x10(2)-1.4x10(5) CFU/100 ml, respectively. The total bacterial counts and bacterial indicators (total coliforms, faecal coliforms and faecal streptococci) were detected in all samples during the period of study, and the count increased in samples collected during summer than other seasons. Also total yeasts, A. hydrophila and total staphylococci were detected in all samples with differences in count between the sites. In contrast, other microbial parameters, Candida albicans, salmonellae, total vibrios and Listeria group were not detected in some samples at some sites. According to our results it can be concluded that the river Nile is categorized as an intermediately polluted river.