DETERMINATION OF SURVIVAL RATES FOR SELECTED BACTERIAL AND PROTOZOAN PATHOGENS FROM WET WEATHER DISCHARGES

摘要

Pathogenic organisms found in sewage can adversely impact public health when thernsewage is discharged to waters that humans come in contact with through wading,rnswimming, fishing, drinking, etc. UAB is conducting research to develop a riskrnassessment methodology for evaluating varying degrees of risk related to humanrncontact with pathogenic microorganisms found in sewage contaminated waters,rnespecially those caused by separate sanitary sewer overflows (SSOs). Onerncomponent of this research is to study the fate and transport of these microorganismsrnin the environment. The survivability, or die-off, rates for these organisms is critical tornunderstanding their fate in the environment, e.g., from an SSO discharge through arnreceiving water.rnSince there are a multitude of factors that contribute to microorganism survivability,rnthe use of an in-situ method to characterize the rates of growth and death isrnnecessary to account for variable environmental conditions. Hence, thesernexperiments were conducted using a specially designed in-situ chamber.rnThis research was shown to be useful in obtaining survivability data based on thernactual conditions present in an SSO polluted stream, and when combined withrnhydrologic data, can be used to predict the fate of pathogens downstream from arnpoint source discharge of sanitary sewage. The information from these experimentsrncan be used to construct a fitted-curve, which can then be used to determine a rate ofrndecay for input into the computer model.rnThe results of this research could be applied to the construction of a fate andrntransport model, which could then be used by a community to target remediationrnefforts to those discharge points of highest public health concern. A model, tailored torna particular community, could be built, which would allow one to rank SSO dischargernpoints from those of highest to lowest health risk. Therefore, use of this methodologyrnwould allow municipalities to apply their limited funds to the repair of dischargesrncreating the greatest health risk first.