Anaerobic BTEX biodegradation linked to nitrate and sulfate reduction

Dou, Junfeng; Liu, Xiang; Hu, Zhifeng; Duan, Dong

doi:10.1016/j.jhazmat.2007.06.043

Cited by 60 publications

(34 citation statements)

References 25 publications

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“…Nitrogen is one of the most essential elements for living, and nitrate is an electron acceptor. These findings are consistent with other published reports [2,27]. In the first-phase experiment (biostimulation) for system A, DO functioned as an electron acceptor; whereas, NO 3 --N can be assumed to promote the capacity of the biodegradation [2].…”

Section: Btex Removal Efficiencysupporting

confidence: 92%

Microbial communities and biodegradation in lab-scale BTEX-contaminated groundwater remediation using an oxygen-releasing reactive barrier

Lin

Chen

Yet-Pole

et al. 2009

Bioprocess Biosyst Eng

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To remediate benzene, toluene, ethylbenzene and xylene (BTEX) -contaminated groundwater, a biotreatment process including biostimulation and bioaugmentation was simulated using oxygen-releasing reactive barriers (ORRB) and water with added BTEX in a lab-scale system. The results showed that the capability for BTEX removal decreases in the order of benzene, toluene, p-xylene, ethylbenzene for both added-nitrogen and noadded-nitrogen under BTEX concentrations at 30 mg l -1 . The removal efficiencies in ORRB systems were higher in the nitrogen-added condition for biostimulation compared with the no-nitrogen-added condition; moreover, an increased pattern for removal was observed during the bioaugmentation process. The oxygen content was found to be inversely proportional to the distance from the ORRB, as evidenced by observing that the average bacteria densities were two orders higher when located at 15 cm compared with 30 cm from the ORRB. The microbial community structure was similar in both cases of addednitrogen and the no-added-nitrogen conditions.

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Section: Btex Removal Efficiencysupporting

confidence: 92%

Microbial communities and biodegradation in lab-scale BTEX-contaminated groundwater remediation using an oxygen-releasing reactive barrier

Lin

Chen

Yet-Pole

et al. 2009

Bioprocess Biosyst Eng

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“…For example, it has been reported that toluene, ethylbenzene and xylene make up about 18% by volume in gasoline (An 2004;Plaza et al 2007). Because of the relatively high water solubility and low K ow values, these compounds are highly mobile in the environment (Dou et al 2008). The presence of these hydrocarbons in the environment is a hazard to public health and an ecological concern due to their toxicity and ability to bioaccumulate through food chain, and they are classified as environmental priority pollutants in many countries (Plaza et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Oxidative stress and DNA damage in the earthworm Eisenia fetida induced by toluene, ethylbenzene and xylene

et al. 2010

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Superoxide dismutase (SOD), guaiacol peroxidase (POD), catalase (CAT), and the comet assay (SCGE) were used as biomarkers to evaluate the oxidative stress and genotoxicity of toluene, ethylbenzene and xylene in earthworms (Eisenia fetida). The results indicated that the exposure of the three pollutants caused a stress response of the three enzymes, an approximate bell-shaped change (a tendency of inducement firstly and then inhibition with increasing concentrations of the pollutants) was mostly found. The three enzymes tested differed in their sensitivity to different pollutants. While the activity of POD was not significantly changed within the concentration range, the concentration thresholds for significant (P < 0.05) responses to toluene based on SOD and CAT were 5 mg kg(-1), respectively. Similarly, the concentration thresholds for significant (P < 0.05) responses to ethylbenzene based on CAT and POD were 10 and 5 mg kg(-1), respectively, while the activity of SOD was not significantly changed within the concentration range. Significant responses to xylene based on CAT and POD were 5 mg kg(-1), respectively, while the activity of SOD was significantly (P < 0.05) induced at 10 mg kg(-1). The SCGE assay results showed that these three pollutants could significantly (P < 0.01) induce DNA damage in earthworms and the clear dose-dependent relationships were displayed, indicating potential genotoxic effects of toluene, ethylbenzene, and xylene on E. fetida. The inducement of DNA damage may be attributed to the oxidative attack of toluene, ethylbenzene, and xylene. Toluene seemed to be more genotoxic as it could induce the higher extent of DNA damage than ethylbenzene and xylene. The results suggest that the SCGE assay of earthworms is simple and efficient for diagnosing the genotoxicity of pollutants in terrestrial environment.

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“…The method of sulfate determination was Photometric method by Barium chromate using a spectrophotometer (Shimadzu, Japan) at 420 nm [8]. While sulfide was determined by the methylene blue formation reaction using the same spectrophotometer (Shimadzu, Japan) at 665 nm [9]. All the items (V, pH, sulfate and sulfide) were measured periodically.…”

Section: Methodsmentioning

confidence: 99%