ABSTRACT
The survival potential of microbial pathogens in groundwater and injected reclaimed water (tertiary treated effluent) was assessed to determine the relative risk associated with an Aquifer and Storage and Recovery (ASR) scheme. The microbial pathogens tested were poliovirus, coxsackievirus, Salmonella typhimurium, the opportunistic pathogen Aeromonas hydrophila; as well as the indicator microorganisms Escherichia coli and the coliphage MS2. The results obtained indicated that the bacteria had the largest decay rates followed by the coliphage MS2, with the enteric viruses decaying the least of all the organisms tested. Decay rates of all of the microorganisms were the highest in the presence of indigenous groundwater microorganisms. It can be inferred from these results that the risk of microbial pathogen presence in recovered water is low if the reclaimed water is stored in the aquifer for time periods larger than those determined from the decay rates for the different pathogens to enable effective removal.
