Enhancement of nitrate-induced bioremediation in marine sediments contaminated with petroleum hydrocarbons by using microemulsions

Zhang, Zhen; Zheng, Guanyu; Lo, Irene M. C.

Enhancement of nitrate-induced bioremediation in marine sediments contaminated with petroleum hydrocarbons by using microemulsions

2015

Zhang, Zhen | Zheng, Guanyu | Lo, Irene M. C.

The effect of microemulsion on the biodegradation of total petroleum hydrocarbons (TPH) in nitrate-induced bioremediation of marine sediment was investigated in this study. It was shown that the microemulsion formed with non-ionic surfactant polyoxyethylene sorbitan monooleate (Tween 80), 1-pentanol, linseed oil, and either deionized water or seawater was stable when subjected to dilution by seawater. Desorption tests revealed that microemulsion was more effective than the Tween 80 solution or the solution containing Tween 80 and 1-pentanol to desorb TPH from marine sediment. In 3 weeks of bioremediation treatment, the injection of microemulsion and NO₃ ⁻ seems to have delayed the autotrophic denitrification between NO₃ ⁻ and acid volatile sulfide (AVS) in sediment compared to the control with NO₃ ⁻ injection alone. However, after 6 weeks of treatment, the delaying effect of microemulsion on the autotrophic denitrification process was no longer observed. In the meantime, the four injections of microemulsion and NO₃ ⁻ resulted in as high as 29.73 % of TPH degradation efficiency, higher than that of two injections of microemulsion and NO₃ ⁻ or that of four or two injections of NO₃ ⁻ alone. These results suggest that microemulsion can be potentially applied to enhance TPH degradation in the nitrate-induced bioremediation of marine sediment.

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