Evaluation of coliphages in sewage effluent of Faisalabad.

One hundred and ten samples of Sewage were collected from both underground sewage and open drain systems of Faisalabad for coliphage assay. It was observed that the samples from underground sewage system ranged from 8.43 X 10(3)--4.65 X 10(3) in mean plaque forming units (PFU) per ml, whereas the corresponding figures in open drain system varied from 8.66 X 10(3)--3.21 X 10(3) mean PFU per ml. In general, samples from congested areas of both the systems studied tended to be richest both in mean PFU per ml as well as plaque morphological variations. Overall 620 plaque morphological classes were isolated. It was also noted that the mean PFU per ml was higher in the summer than in the winter months and phage contents were increased after rain fall.