炭铁可渗透反应墙修复氯代烃及淤堵性能研究

The remediation and clogging performance of chlorinated hydrocarbons treated by biochar-iron permeable reactive barrier

通过PRB室内柱实验,对PRB在修复氯代烃污染地下水过程中(24h内的不同时间点)的渗透性能,淤堵程度,修复效果等方面开展相关研究.研究结果发现,24h内炭铁复合材料渗透系数随着时间的增加而增加.PRB模拟柱运行4h时复合材料对三氯乙烯(TCE)的去除率最高为74.23%,在8h时该去除率最低为64.59%.复合材料对TCE去除率的变化是多影响因子多方位综合作用的结果.渗透系数较低时,水流速度较慢,并且系统内不断有(OH)-产生,各种离子沉淀反应稳定发生且反应完全,导致PRB系统淤堵程度不断提高;高渗透性能的条件下,水流速度快,系统内虽有较高浓度(OH)-,该条件沉淀反应不完全,冲刷占主导,导致淤堵程度会降低.

Column tests were used to study the permeability,clogging and remediation performance of PRB in treating chlorinated hydrocarbon-contaminated groundwater(at different time points within 24hours).The results show that the permeability of carbon iron composite increased with time in 24hours.The removal rate of these PRB columns was the highest at 74.23%after 4hs of operation.The removal rate of which decreases to 64.59%after 8hs’operation.The removal rate of PRB reactive materials in remediating trichloro ethylene was affected by multiple factors.When the permeability of PRB is low,the water flow rate through which is low as well.Under this condition,hydroxide ions are formed in these PRB system.Hence,ions in the groundwater are precipitated stably and completely,which leads to the clogging of the PRB system.When the water flow is fast,although there are hydroxide ions generated all the time,flushing leads to a higher permeability of the PRB system.