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Aerobic biodegradation of
a mixture of chlorinated organics in contaminated water
A. O. Olaniran*, V. Bhola
and B. Pillay
Discipline
of Microbiology, School of Biochemistry, Genetics,
Microbiology and Plant Pathology, Faculty of Science and
Agriculture, University of KwaZulu-Natal (Westville Campus),
Private Bag X 54001, Durban 4000, South Africa.
*Corresponding
author. E-mail:
olanirana@ukzn.ac.za. Tel: + 27 31 260 7400/7401. Fax: +
27 31 260 7809.
Accepted
20 May, 2008 |
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The environmental persistence, toxicity and/or
carcinogenicity of chlorinated aliphatic compounds (CAHs)
and their potential for bioaccumulation in food chains has
made them of serious environmental concern. The frequency of
a mixture of these compounds encountered in most
contaminated sites has warranted investigation into their
fate in contaminated sites. In this study, therefore, the
biodegradation of a mixture of CAHs; namely, carbon
tetrachloride (CCl4), 1,2-dichloroethane (DCA)
and dichloromethane (DCM), in contaminated water microcosms
was investigated. The mixture of CAHs investigated was
observed to be simultaneously degraded in both microcosms
with up to 86.28% CCl4, 44.64% DCM and 52.34% DCA
degradation observed in the untreated microcosms. The
degradation rate constants of the CAHs ranged variously
between 0.168 – 1.234 week-1 for CCl4;
0.175 – 0.832 week-1 for DCM; and 0.232 – 0.588
week-1 for DCA in both water microcosms with
higher degradation generally observed in New Germany
Wastewater compared to those in Northern Wastewater.
Findings from this study also suggest that biostimulation
and/or bioaugmentation is required to speed up the
biodegradation process, depending on the available nutrients
and the presence or absence of microbial population capable
of CAHs’ metabolism at the contaminated sites.
Key
words:
Bioaugmentation, biodegradation, biostimulation, chlorinated
aliphatic hydrocarbons, microcosms. |
