两种氧化体系联合生物刺激修复总石油烃污染土壤

Remediation of total petroleum hydrocarbon contaminated soil using two different oxidation systems combined with biostimulation

采用Fenton试剂和铁活化Na_(2)S_(2)O_(8)两种氧化体系耦合生物刺激修复总石油烃(TPH)污染土壤。在H_(2)O_(2)投加量为6%(w)、n(Fe^(2+))∶n(H_(2)O_(2))为0.20的最佳工艺条件下,TPH去除率达52.38%;在Na_(2)S_(2)O_(8)投加量为3%,n(Fe^(2+))∶n(Na_(2)S_(2)O_(8))为0.10的最佳工艺条件下,TPH去除率达71.83%。投加两种氧化剂后,土壤中土著微生物数量均大幅下降,添加外源营养物生物刺激后Fenton体系中微生物数量迅速回升,铁活化Na_(2)S_(2)O_(8)体系恢复稍慢,但微生物数量均能在30 d内恢复到原有水平。Fenton氧化耦合生物刺激最终TPH降解率达85.45%,TPH残留量为1718 mg/kg;铁活化Na_(2)S_(2)O_(8)耦合生物刺激最终TPH降解率达93.02%,TPH残留量为813 mg/kg,两者均达到了2050 mg/kg的场地TPH修复目标值。

Two oxidation systems containing Fenton reagent and Fe-activated Na_(2)S_(2)O_(8) respectively,coupled with biostimulation were applied for the remediation of total petroleum hydrocarbon(TPH)contaminated soil.The TPH removal rate reaches 52.38%under the optimal process conditions of H_(2)O_(2) amount 6%(w)and n(Fe^(2+))∶n(H_(2)O_(2))=0.20,and 71.83%under the optimal process conditions of Na_(2)S_(2)O_(8) amount 3%and n(Fe^(2+))∶n(Na_(2)S_(2)O_(8))=0.10.With addition of the two oxidants,indigenous microorganism in soil is significantly decreased.After biostimulation with exogenous nutrients,microorganism in the Fenton system rises again rapidly;while that in the Na_(2)S_(2)O_(8) system recoveres at a slightly slower speed,but can recover to the original level within 30 d.The eventual TPH degradation rate by Fenton oxidation coupled with biostimulation is 85.45%,with the TPH residue being 1718 mg/kg;while,that by Na_(2)S_(2)O_(8) coupled with biostimulation is 93.02%,with the TPH residue being 813 mg/kg.Both are all lower than TPH remediation target value of 2050 mg/kg.