Purpose

The objectives of this study were to explore the effects of bulking agent and nutrients on the pore characteristics, remediation efficiency, and biotoxicity of petroleum hydrocarbon-contaminated soil. Furthermore, the correlation among the three characteristic indices was studied.

Methods

Three pilot-scale biopiles were constructed to treat aged petroleum-contaminated soil. Micro-CT was applied to obtain the pore characteristics of piles.

Results

The results showed that the addition of bulking agent had a positive effect on the pore development of the biopile. The porosity of the pile was increased from 0.33 to 3.32% of the control pile to 4.41 to 26.93%, and the addition of bulking agent showed a significant positive effect on the Feret diameter. However, the addition of nutrients had no significant effect on the porosity and Feret diameter. Besides, the total petroleum hydrocarbon removal rate of bulking agent pile (36.82–49.18%) was significantly higher than that of nutrient piles (20.07–23.43%) and control piles (17.57–27.08%). The bulking agent pile had the lowest toxicity. The porosity of the pile, total petroleum hydrocarbons removal rate, and the characteristic values of biotoxicity (EC50) showed a positive correlation.

Conclusion

Bulking agents might promote gas circulation by improving the pore structure of the biopile. And the metabolic activity of microorganisms increased as a result of the promotion of the microbial habitat. The higher biodegradation of petroleum hydrocarbons was achieved. However, the main finding of this research is that adding bulk agent to petroleum-contaminated soil significantly increases biodegradation of petroleum. This may be inapplicable to other soils with a different clay content or porosity.

中文翻译：

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在田间规模生物堆处理中添加填充剂改善石油污染土壤的孔隙特征、修复效率和生物毒性

目的

本研究的目的是探讨填充剂和养分对石油烃污染土壤孔隙特征、修复效率和生物毒性的影响。此外，研究了三个特征指标之间的相关性。

方法

建造了三个中试规模的生物堆来处理老化的石油污染土壤。Micro-CT 被应用于获得桩的孔隙特征。

结果

结果表明，填充剂的加入对生物桩的孔隙发育有积极影响。桩的孔隙率由对照桩的0.33～3.32%提高到4.41～26.93%，填充剂的加入对Feret直径有显着的正向影响。然而，添加养分对孔隙率和 Feret 直径没有显着影响。此外，膨胀剂桩的总石油烃去除率（36.82-49.18%）显着高于营养桩（20.07-23.43%）和控制桩（17.57-27.08%）。填充剂堆的毒性最低。桩的孔隙率、总石油烃去除率和生物毒性特征值（EC50）呈正相关。

结论

填充剂可以通过改善生物堆的孔隙结构来促进气体循环。由于微生物栖息地的促进，微生物的代谢活动增加。实现了对石油烃的更高生物降解。然而，这项研究的主要发现是，在受石油污染的土壤中添加散装剂会显着增加石油的生物降解。这可能不适用于具有不同粘土含量或孔隙率的其他土壤。