RESUMEN
Waste stabilization pond system at Lahore, Pakistan, consisting of one anaerobic, two facultative and two maturation ponds was studied for eighteen months [December 1984 to June 1986] to study pond performances in terms of indicator organisms, pathogens and parasites removals. In all, four phases were investigated, the ponds were able to remove significant amount of total Coliforms, E. Coliforms and F. Streptococci; substantial amount of Salmonella, Shigella and Pseudomonas species; and completely E. histolytica, Ascaris and Hook-worms. The results obtained were in close agreement with Marais model of bacteria removal in waste stabilization ponds. The effluent so obtained can be safely utilized for irrigation, especially for crops which are not eaten raw