不同污染时长土壤中石油烃的生物去除特性及影响因素

利用生物刺激法修复不同污染时长的土壤,比较了向新污染(污染7 d)和陈旧性污染(污染5 a以上)土壤中加入有机肥、有机肥+KNO_3复合物(C∶N=100∶10)、脱硫石膏等处理剂对土壤中石油烃的去除效果。结果表明:对于新污染黄绵土,向土壤中加入有机肥、有机肥+KNO_3对土壤中石油烃去除效果较好,修复150 d时土壤中石油烃去除率分别为60.13%、56.09%;对于陈旧性污染土壤,施入有机肥+KNO_3、脱硫石膏对石油烃去除效果较好,修复150 d时土壤中石油烃的去除率分别为36.62%、36.61%;生物刺激对新污染土壤中石油烃的去除效率高于陈旧性污染土壤。两种不同污染时长土壤中的石油烃生物降解均符合伪一级动力学。生物刺激修复使土壤的pH值由8.50～8.56降低至7.35～7.91。新污染土壤中石油烃的降解率与pH值呈显著负相关(相关系数为-0.789),与微生物数量呈显著正相关(相关系数为0.849);陈旧性污染土壤中石油烃降解率与土壤pH值呈显著负相关(相关系数为-0.683)。研究表明,土壤受到石油污染后立即进行生物刺激修复有利于土壤中石油烃的去除,影响不同污染时长土壤中石油烃生物降解的关键因素并不相同。

Biological removal efficiency and influencing factors of petroleum hydrocarbons in soil with different polluted time

Petroleum hydrocarbon removal efficiencies in freshly/aged contaminated loessal soil were analyzed by adding organic fertilizer, organic fertilizer plus KNO₃(C:N=100:10), and desulfurized gypsum as biostimulant agents. Results showed that after 150 days of remediation, petroleum hydrocarbon removal efficiencies were 60.13% and 56.09% in the freshly contaminated soils treated with organic fertilizer and organic fertilizer plus KNO₃, respectively, which were higher than that of treated with desulfurized gypsum. In the aged contaminated soil, the hydrocarbon removal efficiencies were 36.62% and 36.61% in the soils treated with organic fertilizer plus KNO₃ and desulfurized gypsum, respectively. The petroleum removal efficiencies were higher in the freshly contaminated soil than those in the aged contaminated soil. In both the freshly and aged contaminated soil, the petroleum hydrocarbon biodegradation efficiencies conformed to pseudo first-order kinetics. Soil pH decreased from 8.50~8.56 to 7.35~7.91 owing to bioremediation. In the freshly contaminated soil, hydrocarbon biodegradation efficiency positively correlated with the number of soil microorganisms with the correlation coefficient of 0.849; however, the hydrocarbon biodegradation efficiency negatively correlated with pH with the correlation coefficient of -0.789. In the aged contaminated soil, the hydrocarbon biodegradation efficiency negatively correlated with pH, and the correlation coefficient was -0.683. These results indicate that biostimulation remediation is more effective for hydrocarbon removal in the freshly contaminated loessal soil than that in the aged contaminated soil. The key factors affecting petroleum hydrocarbon biodegradation in soils with different pollution time frames are different.