(73d) Bioremediation of Petroleum-Contaminated Soil Using Three Simultaneously Operated Bioreactors
Nowadays, many of human activities such as heating, transportation and power production need oil-derivative fuels. There are many refineries that have been contaminated by petroleum hydrocarbons through various stages of exploration, production, transport and storage. Physiochemical and biological treatment methods have been known to remediate contaminations. For example, in biological remediation methods microorganismsis can be used to remediate contaminants. These methods are considered as a cost-effective and environmental friendly solution. In our research, two bacterial strains which had the highest total petroleum hydrocarbon (TPH) degradation efficiency were isolated from contaminated soil of a refinery. The strains were identified using biochemical tests and 16S rRNA analysis as Pseudomonas aeruginosa and Bacillus Subtilis . Pseudomonas aeruginosa and Bacillus Subtilis could respectively degrade 87% and 75% of total hydrocarbons in flasks containing 2% diesel and 98% water during 20 days of operation. Then four bioremediation modes in parallel-operated bioreactors were studied in order to find the best biological technique in remediation of petroleum contaminants. Natural attenuation, biostimulation, bioaugmentation, and combination of biostimulation and bioaugmentation were studied in the bioreactors. Total Petroleum Hydrocarbons (TPH) and microbial population as criteria to compare the efficiency of the methods were measured. Finally, first oreder kinetic model and Monod model were studied and kinetic parameters were determined in order to permit scale-up to field-scale operation of treatment processes.