Enumeration of Pseudomonas species and Pseudomonas aeruginosa bacteriophages in domestic sewage.

Domestic sewage in Kuwait is mainly treated by an activated sludge process. Pseudomonas species were enumerated at all steps of sewage treatment. About 98-99% reduction in the number of these bacterial species were found in the treated effluent compared with raw sewage, which indicates a rather efficient removal of Pseudomonas from sewage. Spherical tail-less phages of Pseudomonas aeruginosa were found in all sewage samples. About 25-85% of the total phages encountered with the raw sewage were retained in the treated effluents. Seasonal variations of Pseudomonas spp and P. aeruginosa phages in two treatment stations are reported.