生物堆修复城市多环芳烃污染土壤的调控研究

土壤多环芳烃(PAHs)污染已成为一种严重的全球性城市环境问题。以通风时间、绿肥、无机营养剂和疏松剂含量为调控因素,利用现场规模的正交试验进行了生物堆修复城市多环芳烃污染土壤的调控研究。结果表明,所有生物堆处理对土壤PAHs的去除均有一定促进作用,75 d时平均降解率为30.63%~80.41%,且深层土壤降解率比表层土壤高8.55%;运行期间各调控因素对不同深度土壤PAHs降解的影响程度和作用规律各不相同,其中通风时间始终是主导因素,且通风时间越长,降解效果越好;生物堆的最佳运行条件总体上为通风时间3 h、绿肥3.5%、营养剂0.2%、疏松剂18%(表层土壤)或14%(深层土壤)。因此,利用生物堆修复城市PAHs污染土壤是有效的,且增加通风时间是提高其修复效率的优先调控方式。

Regulation of Biopile for PAH Removal in Urban Contaminated Soil

Soil contamination with polycyclic aromatic hydrocarbons(PAHs) has become a considerable environmental problem in global cities.Taking ventilation time,manure,inorganic nutrient and bulking agent content as regulation factors,the regulation of field-scale biopile for PAH removal in urban contaminated soil was conducted by orthogonal test.Results showed that all biopile treatments could promote PAH removal more or less.After 75 d,average PAH degradation rates were 30.63%~80.41%,and degradation rate in deep soil was 8.55% higher than that in surface soil.During biopile operation,regulation factors had different influence degrees and rules on PAH degradation in different depths of soil,and ventilation time was always the dominant factor for biopile regulation,the increase of which could improve PAH degradation.The optimal condition for biopile operation was 3 h ventilation time,3.5% green manure,0.2% inorganic nutrient and 18% surface soil or 14% deep soil bulking agent.The application of biopile in remediating urban soil contaminated with PAHs is effective,and increasing ventilation time should be chosen preferentially to improve the removal efficiency.