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Enhanced Bioremediation of Fuel-Oil Contaminated Soils: Laboratory Feasibility Study |
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| Authors: | T. T. Tsai C. M. Kao Rao Y. Surampalli H. Y. Chien |
| Affiliation: | 1Postdoctoral Fellow, Institute of Environmental Engineering, National Sun Yat-Sen Univ., Kaohsiung 804, Taiwan. 2Professor, Director, Institute of Environmental Engineering, National Sun Yat-Sen Univ., Kaohsiung 804, Taiwan (corresponding author). E-mail: jkao@mail.nsysu.edu.tw 3Engineer Director, USEPA, Kansas City, KS. 4Ph.D. Candidate, Institute of Environmental Engineering, National Sun Yat-Sen Univ., Kaohsiung 804, Taiwan. |
| Abstract: | In this study, microcosm experiments were conducted to evaluate the effectiveness of (1) nutrients, hydrogen peroxide (H2O2), and cane molasses addition; (2) soil washing by biodegradable surfactant [Simple Green (SG)]; and (3) soil pretreatment by Fenton-like oxidation on the bioremediation of fuel-oil contaminated soils. The dominant native microorganisms in the fuel-oil contaminated soils after each treatment process were determined via polymerase chain reaction, denaturing gradient gel electrophoresis, and nucleotide sequence analysis. Results show that approximately 32 and 56% of total petroleum hydrocarbon (TPH) removal (initial concentration of 5,000?mg?kg?1) were observed in microcosms with the addition of nutrient and cane molasses (1,000?mg?L?1), respectively, compared to only 9% of TPH removal in live control microcosms under intrinsic conditions (without amendment) after 120 days of incubation. Addition of cane molasses would cause the increase in microbial population and thus enhance the TPH degradation rate. Results also show that approximately 61% of TPH removal was observed in microcosms with the addition of H2O2(100?mg?L?1) and nutrient after 120 days of incubation. This indicates that the addition of low concentration of H2O2(100?mg?L?1) would cause the desorption of TPH from soil particles and increase the dissolved oxygen and subsequent bioremediation efficiency in microcosms. Approximately 95 and 69% of TPH removal were observed in microcosms with SG (100?mg?L?1) and higher dose of H2O2(900?mg?L?1) addition, respectively. Moreover, significant increases in microbial populations were observed and two TPH biodegraders (Pseudomonas sp. and Shewanella sp.) might exist in microcosms with SG or H2O2 addition. This indicates that the commonly used soil remedial techniques, biodegradable surfactant flushing, and Fenton-like oxidation would improve the TPH removal efficiency and would not cause adverse effects on the following bioremediation process. |
| Keywords: | Soil pollution Oils Petroleum Biological treatment Soil treatment |