Escherichia coli die-off in swine wastewater lagoons
In Malaysia, pig farming grew rapidly due to high demand. It is one of the most polluting livestock industries in Sarawak resulting in water and air pollution. Escherichia coli (E. coli) is used as an indicator for water quality and for possible presence of pathogenic microorganisms in water. Thi...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
2007
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| Subjects: | |
| Online Access: | http://ir.unimas.my/id/eprint/28813/2/Escherichia%20coli%20Die-Off%20in%20Swine%20Wastewater%20Lagoons.pdf |
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| Summary: | In Malaysia, pig farming grew rapidly due to high demand. It is one of the most
polluting livestock industries in Sarawak resulting in water and air pollution.
Escherichia coli (E. coli) is used as an indicator for water quality and for possible
presence of pathogenic microorganisms in water. This study is done to determine the
biotic and abiotic effect on E. coli survival, the predominant factor in E. coli die-off,
comparing survival in laboratory and field studies, and to evaluate wastewater
lagoons efficiency. Wastewater samples for the laboratory studies were collected from
wastewater lagoons of a farm in Gedon0 t was observed that E. coli population
increased and maintained at high concentration in sterile wastewater compared to
the non-sterile wastewater under the same condition in the laboratory study. This is
possibly due to biotic factor as protozoa number was found to increase up to 8 10glO
unitlmL as E. coli population dropped. Results showed that E. coli removal was
enhanced by lethal pH - with pH level of more than 9 in the laboratory study. The
study of E. coli survival was carried out in the laboratory and also in the field. The
die-off rates ranged from 0.144 d· l to 2.835 d· l in laboratory study. Under field
investigation (field batch study), the die-off rates ranged from 0.172 d· l to 1. 767 d· l . In
both laboratory and field batch studies, E. coli decay rates in the wastewater from
Lagoon 2 (L2) and Lagoon 3 (L3) were found to be much higher than in primary
lagoons, Lagoon lA (LIA) and Lagoon IB (LIB). In both studies, it was found that
there was no significant difference between die-off rates in LIA and LIB wastewater.
In the field experiment, the two 7 -day field studies in September and October 2005
showed that E. coli concentrations dropped 2 10glO units after wastewater flowing
through the lagoons. In addition, the lagoon system in the farm studied resulted in E.
coli reduction with highest percent reduction occurred in L2 (74.9%). Correlation
analysis showed that E. coli die-off rates were highly and significantly correlated
with DO and pH levels. |
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