Water, Sewage & Effluent July August 2018 | Page 31

Faecal coliform testing is one of the
nine tests of water quality that form
the overall water-quality rating in a
process used by the EPA, which also
reflects in South African ratings.
SANS 241 standards
• SANS 241 Table 1 (Microbiological
safety requirements) column 3:
Allowable Compliance Contribution
(95% of samples min.). Upper limit:
Not detected (count per 100mℓ)
Apart from the human health issues,
untreated faecal material, such
as contains faecal coliform, adds
excess organic material to the water.
The decay of this material depletes
the water of oxygen. This lowered
oxygen may kill fish as well as other
aquatic organisms. When the use
of chlorine and other disinfectant
chemicals is required for the reduction
of faecal coliform in wastewater, it
may require such materials to kill the
faecal coliform and disease bacteria.
These also kill bacteria essential to
the proper balance of the aquatic
environment, resulting in endangering
the survival of species dependent on
those bacteria. So, higher levels of
faecal coliform require higher levels
of chlorine, threatening those aquatic
organisms.
Water Sewage & Effluent July/August 2018
29
Faecal coliform testing
The primary sources of faecal
coliform bacteria to freshwater
are wastewater treatment
plant discharges, failing septic
systems, and animal waste.
The presence of faecal coliform
tends to affect humans more than it
does aquatic creatures, though not
exclusively. While these bacteria do not
directly cause disease, high quantities
of faecal coliform ba cteria suggest the
presence of disease-causing agents.
The presence of faecal contamination
is an indicator that a potential health
risk exists for individuals exposed to
this water.
Faecal coliform, like other bacteria,
can usually be killed by either boiling
water or by treating it with chlorine.
Washing thoroughly with soap after
contact with contaminated water can
also help prevent infections.
• S
 ANS 241 Table 1 (Microbiological
safety requirements) column 4:
Allowable Compliance Contribution
(4% of samples max.). Upper limit:
Not detected (count per 100mℓ)
• SANS 241 Table 1 (Microbiological
safety requirements) column 5:
Allowable Compliance Contribution
(1% of samples max.). Upper limit: 1
(count per 100mℓ).
innovations
a. F  aecal coliform bacteria may enter
rivers through direct discharge of
waste from mammals and birds,
from agricultural and storm run-
off, and from untreated human
sewage.
b. Individual home septic tanks can
become overloaded during the
rainy season and allow untreated
human wastes to flow into drainage
ditches and nearby waters.
c. 
Agricultural practices such as
allowing animal wastes to wash
into nearby streams during the
rainy season, spreading manure
and fertiliser on fields during
rainy periods, and allowing
livestock watering in streams can
all contribute to faecal coliform
contamination.
d. 
During high rainfall periods, the
sewer can become overloaded and
overflow, bypassing treatment. As
it discharges to a nearby stream or
river, untreated sewage enters the
river system. Run-off from roads,
parking lots, and yards can carry
animal wastes to streams through
storm sewers.
e. A
 t the time this occurs, the source
water may be contaminated by
pathogens or disease-producing
bacteria or viruses, which can
also exist in faecal material. Some
waterborne pathogenic diseases
include ear infections, dysentery,
typhoid fever, viral and bacterial
gastroenteritis, and hepatitis A.
The mere presence of faecal coliform
bacteria in aquatic environments
indicates that the water has been
contaminated with the faecal material
of man or other animals:
Escherichia coli magnified 10 000 times the original.
Factors that contribute
to faecal coliform
contamination
The presence of faecal coliform
bacteria in an aquatic environment
indicates that the water has been
contaminated with the faecal material,
either by humans and/or other animals.
There is also the strong possibility
that the source water may have been
contaminated by pathogens, disease-
producing bacteria or viruses, which
can also exist in faecal material. Some
waterborne
pathogenic
diseases
include typhoid fever, viral and bacterial
gastroenteritis, and hepatitis A.
The conclusion is that the presence
of faecal contamination serves as an
indicator that a potential health risk
exists for individuals exposed to this
water, and of environmental concern is
the presence of the variety of types of
coliform bacteria.
By growing and counting colonies of
faecal coliform bacteria from a sample
of stream water, it makes it possible
to determine with a fair amount of
accuracy how many bacteria were
present originally.
Environmental