title: Impact of chemical oxidation on indigenous bacteria and mobilization of nutrients and subsequent bioremediation of crude oil-contaminated soil.
abstract: Fenton pre-oxidation provides nutrients to promote bioremediation. However, the effects of the indigenous bacteria that remain following Fenton oxidation on nutrient mobilization and subsequent bioremediation remain unclear. Experiments were performed with inoculation with native bacteria and foreign bacteria or without inoculation after four regimens of stepwise pre-oxidations. The effects of the indigenous bacteria remaining after stepwise oxidation on nutrient mobilization and subsequent bioremediation over 80 days were investigated. After stepwise Fenton pre-oxidation at a low H2O2concentration (225×4), the remaining indigenous bacterial populations reached their peak (4.8±0.17×106CFU/g), the nutrients were mobilized rapidly, and the subsequent bioremediation of crude oil was improved (biodegradation efficiency of 35%). However, after stepwise Fenton pre-oxidation at a high H2O2concentration (450×4), only 3.6±0.16×103CFU/g of indigenous bacteria remained, and the indigenous bacteria that degrade C15-C30alkanes were inhibited. The nutrient mobilization was then highly limited, and only 19% of total petroleum hydrocarbon was degraded. Furthermore, the recovery period after the low H2O2concentration stepwise Fenton pre-oxidation (225×4) was less than 20 days, which was 20-30 days shorter than with the other pre-oxidation treatments. Therefore, stepwise Fenton pre-oxidation at a low H2O2concentration protects indigenous bacterial populations and improves the nutrient mobilization and subsequent bioremediation.
authors.affiliation: School of Environmental and Municipal Engineering, Xi'an University of Architecture & Technology, Xi'an, 710055, China. Electronic address: xujinlan@xauat.edu.cn.
authors.forename: Jinlan
authors.initials: J
authors.lastname: Xu
authors.affiliation: School of Environmental and Municipal Engineering, Xi'an University of Architecture & Technology, Xi'an, 710055, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Deng
authors.affiliation: School of Environmental and Municipal Engineering, Xi'an University of Architecture & Technology, Xi'an, 710055, China.
authors.forename: Yiwei
authors.initials: Y
authors.lastname: Cui
authors.affiliation: School of Environmental and Municipal Engineering, Xi'an University of Architecture & Technology, Xi'an, 710055, China.
authors.forename: Fanxing
authors.initials: F
authors.lastname: Kong
mesh_terms: D001673:Biodegradation, Environmental; D006861:Hydrogen Peroxide; D007501:Iron; D010084:Oxidation-Reduction; D010578:Petroleum / Q000378:metabolism*; D059392:Petroleum Pollution; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*
chemical_list: C045076:Fenton's reagent; D010578:Petroleum; D012989:Soil Pollutants; D006861:Hydrogen Peroxide; D007501:Iron
keywords: Bioremediation; Crude oil-contaminated soil; Indigenous bacteria recovery; Nutrient mobilization; Stepwise Fenton oxidation