生物修复石油污染盐碱土壤小试模拟系统中土壤性质与微生物特性变化

利用生物刺激(BS)、生物刺激+生物强化(BS+BA)2种方案修复石油污染盐碱土壤,考察了不同处理小试模拟系统中石油烃及16种多环芳烃(PAHs)的降解率、土壤pH值、表面张力、脱氢酶活性和微生物群落结构的变化.结果表明:腐殖酸、诺沃肥和生物有机钙等土壤改良剂及营养盐的加入使土壤盐碱环境得到明显改善,pH值由8.1~8.2降低至7.6~7.8,并随着酸性代谢产物的累积降低至6.6~7.0.随着微生物活动BS+BA与BS处理土壤溶液表面张力分别由72.2,71.8mN/m降低到64.9,67.2mN/m,提高了石油烃的生物可利用性.对比2组小试系统,BS+BA处理修复效果更加显著,对石油烃、总PAHs的降解率可达到50.8%,69.2%,而BS处理为40.5%和61.2%.其中添加菌剂对5~6环PAHs的去除效果明显.不同修复策略对土壤微生物有显著影响,表现为土壤脱氢酶活性及微生物群落结构的动态变化.

Changes of soil properties and microorganism characteristic during bioremediation of petroleum-contaminated saline soil in microscal simulation study

Bioremediation of petroleum-contaminated saline soil was investigated via biostimulation (BS) and biostimulation-bioaugmentation (BS+BA)in a microscale simulation system. The removal of hydrocarbon and 16 PAHs, changes of soil pH, surface tension, dehydrogenase activity and microbial community structure were monitored during incubation. The results showed that soil properties were changed by the addition of humic acid, NovoGro and biological organic calcium. With the accumulation of acidic metabolites the soil pH decreased from 8.1~8.2 to 6.6~7.0 after remediation. Due to the microbial activities the surface tension of soil had decreased from 72.2 mN/m to 64.9 mN/m in BS+BA treatment and from 71.8 mN/m to 67.2 mN/m in BS treatment, respectively. Thus the bioavailability of petroleum hydrocarbons may be enhanced. The higher removal efficiency was obtained in BS+BA treatment in which 50.8 % of TPH and 69.2 % of total PAHs were degraded, whereas in BS treatment only 40.5% of petroleum hydrocarbon and 61.2% of total PAHs were degraded. Particularly, exotic microorganism showed high efficiency on removal of 5~6 ring PAHs. Different remediation strategies affected soil microbial activity notably, indicated by the dynamic changes of soil enzyme activity and bacterial community structure.