ESTIMATION OF THE FATE OF MICROBIAL WATER-QUALITY CONTAMINANTS IN A SOUTH-AFRICAN RIVER

The aim of this study was to evaluate the validity of assumptions, reg arding assimilative capacity for microbial contaminants, implicit in m icrobial water quality management in South Africa. A one dimensional s teady state stream water quality model, assuming first order decay of microbial water quality variables, was employed in an attempt to descr ibe and predict microbial water quality in the chosen catchment Based on the faecal coliform counts the results indicated that the processes of decay and dilution were inadequate to yield water quality which co mplied with South African and international guidelines for the domesti c and recreational use of water. It was also found that a first order decay model can, with fairly limited data allow a manager to investiga te different microbial water quality scenarios in a cost-effective man ner.