Transcript Indicator Organisms in Wastewater Treatment Wetlands

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.