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Indicator Organisms in Wastewater Treatment Wetlands Jepson Sutton SWES 574 10-31-02 Indicator Organisms • The detection of pathogenic organisms is a time-consuming, labor-intensive task, requiring highly trained technicians • For this reason, scientist have identified certain organisms that, when detected, are a definitive indication of fecal contamination. Indicator Organisms • Indicator organisms are considered normal flora (always present) in the digestive system of all warm-blooded animals, including humans. • The detection of indicator organisms suggests that enteric pathogenic microorganisms may also be present due to the fecal contamination. Characteristics of an effective Indicator • It is normal flora of warm-blooded animals • It is present when pathogens are present, and undetected in uncontaminated samples • The indicator should be found in greater concentrations than pathogens. • It should have a similar resistance to environmental stress and water treatment processes as the pathogen. Characteristics of an effective Indicator • It must require a host for replication. (eliminates replication in the environment) • Rapid, easy, and inexpensive detection methods • Nonpathogenic Types of indicator organisms • Total coliforms – First group of indicators developed – Problematic because of the ability of some species to replicate in the environment • Fecal coliforms – Subgroup of Total coliforms – Restricted to fecal origins • Fecal Streptococci – Primarily an indication of animal fecal pollution – FC/FS ratio Types of indicator organisms • Anaerobic bacteria – Clostridium: spore forming bacteria / environmental resistance – Bacteroides: limited environmental resistance • Bacteriophage – Viruses that require certain bacterial hosts for replication – Indication of both bacterial and viral contamination.