工业化规模生物堆修复焦化类PAHs污染土壤的效果

现场建立处理能力为450 m3工业化规模的生物堆对焦化类PAHs污染土壤进行为期8个月的修复,运行过程中控制土壤C∶N∶P=100∶10∶1、水分10%～20%(质量百分比)、堆内氧气不低于7%(体积百分比)。结果表明:O2与CO2浓度呈负相关。系统连续运行时,微生物数量增加至107数量级,高出自然状态下土壤中微生物数量1～2个数量级。除NO3-在运行后期显著增加外,其余土壤因子均无明显变化。PAHs的降解主要出现在前6个月,之后进入"拖尾"阶段,土壤中各PAH浓度基本不再降低。运行结束后,堆体0.5 m处土壤中含2、3、4、5和6个苯环PAHs的降解率分别介于56.3%～99.5%、34.8%～71.6%、30.7%～40.6%、28.6%～39.2%和39.3%,16种PAHs的平均去除率为65.1%。1.5 m处土壤中含2、3、4、5和6个苯环PAHs的降解率分别介于50.9%～99.8%、57.7%～60.9%、55.9%～63.0%、27.3%～57.1%和52.2%,16种PAHs的平均去除率为71.4%。

Effectiveness of industrialized-scale biopile applied in remediating PAHs contaminated soil

A biopile with a treatment capacity of 450 m3 was constructed on a coke plant site for remediation of PAHs contaminated soil.The biopile was controlled to maintain C/N/P ratio at 100∶10∶1,water content around 10%～20%(w%),and O2 above 7%(v%),respectively during the 8 month operation period.The results reveal that the concentrations of O2 and CO2 were negatively correlated and the microbe density in the soil was 1～2 order higher than the one under natural condition.The soil properties except for NO-3 were not changed obviously.The degradation of PAHs was mainly occurred in the first 6 months and after that the "tailing" phenomenon appeared,the further degradation of PAHs was not significant.After 8 month operation,the degradation rates for PAHs with 2,3,4,5,6 benzene rings at the depth of 0.5 were 56.3%～99.5%,34.8%～71.6%,30.7%～40.6%,28.6%～39.2% and 39.3%,respectively,while the one for PAHs at the depth of 1.5 m were 50.9%～99.8%,57.7%～60.9%,55.9%～63.0%,27.3%～57.1% and 52.2%,respectively.The average degradation rates of 16 PAHs at the depth of 0.5 m and 1.5 m were 65.1% and 71.4%,respectively.