Modeling microbial fate in the subsurface environment

As groundwater is relied upon more and more as a source of drinking water, the practice of recharging groundwater with treated wastewater has become a more attractive means of replenishing depleted groundwater reserves. However, even extensively treated wastewater may contain pathogenic microorganisms, particularly enteric viruses. Once in the soil, these microorganisms, especially the viruses, are capable of migrating considerable distances to reach groundwater, where they pose a potential health hazard to persons consuming the water. Over one half of the waterborne disease outbreaks in the U.S. are due to the use of contaminated groundwater, and microorganisms are the cause of illness in the majority of these outbreaks. Several models have been developed to predict the behavior of microorganisms in the subsurface environment. These models range from conventional, theoretical models of contaminant transport to empirically based models using laboratory and field data. The ultimate goal of the models is to predict microbial behavior so that potential sources of contamination (such as septic tanks and landfills) can be sited in such a way as to minimize microbial contamination of groundwater.