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Environmental
Biotechnology |
Electronic Journal of Biotechnology ISSN: 0717-3458 |
Vol.
11 No. 1, Issue of January 15, 2008 |
© 2008 by Pontificia Universidad Católica
de Valparaíso -- Chile |
Received February 20, 2007 / Accepted July 9, 2007 |
DOI: 10.2225/vol11-issue1-fulltext-4 |
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Ranking agro-technical methods and environmental
parameters in the biodegradation of petroleum-contaminated soils in Nigeria
Reginald B. Kogbara
Department of Agricultural and Environmental
Engineering
Rivers State University of
Science and Technology
P.M.B. 5080, Port Harcourt, Nigeria
Tel: 234 803 293 0133
E-mail: regkogbara@yahoo.com
Keywords: bioremediation methods, performance index,
phytoremediation, total hydrocarbon content.
Abbreviations: |
ANOVA: analysis of variance
HUB: hydrocarbon utilizing bacteria
PAH: polyaromatic hydrocarbon
THB: total heterotrophic bacteria
THC: total hydrocarbon content |
A combination of experimental cells consisting of
some agro-technical methods aimed at accelerating the biodegradation of
petroleum contaminated soils were evaluated in order to ascertain the relevance
of these methods and the relative attention due necessary soil environmental
parameters. The methods of treatment involved the variation of tilling,
watering and nutrient application, plus biopile and phytoremediation
treatments. In the experiments described, petroleum contamination of soils was
simulated under field conditions, the remedial treatments were then utilized
for clean up. Analysis of soil parameters after a six-week study period showed
an increase in total heterotrophic bacteria (THB) counts across all the
treatments, with THB counts increasing with increment in soil nutrient level
and initial concentration of the contaminant. The total hydrocarbon content
(THC) analysis, based on a performance index introduced in this study,
indicated that on the average, the variation of nutrient application, tilling
and watering facilitated the attenuation of THC at the rate of 429.4 mg/kg day,
653.2 mg/kg day, and 327.5 mg/kg day respectively. While the combined effect of
various levels of nutrients, tiling and watering performed at the rate of 558.7
mg/kg day, biopile and phytoremediation treatments recorded 427.9 mg/kg day and
489.3 mg/kg day respectively. These results imply that though nutrient application,
watering and other factors affect the biodegradation process, frequent tilling
for maximum oxygen exposure is the most important factor that affects the
biodegradation of petroleum-hydrocarbons in tropical soils.
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