采用筛板塔吹脱模拟处理四氯乙烯污染地下水

摘要

Perchloroethylene (PCE) as a typical chlorinated hydrocarbon solvent was widely used in industry. Now the groundwater of contaminated sites is badly polluted due to improper handling of PCE, which results in a serious threat to human health and ecological security. Air stripping in sieve plate tower for the treatment of the water polluted by PCE was studied. The results are as follows: After air stripping, PCE concentration declined from 25.68mg/L to 0.62mg/L, and removal rate amounted to 97.59%; Gas-liquid ratio obviously affected PCE removal rate and the optimum gas-liquid ratio was around 200; Initial concentration influenced the removal effect slightly; Waste water was better treated by 4 plates column; Experimental data followed one-order decay model very well; Economic cost was about ￥0.31 per ton of waste water, and therefore air stripping as a pre-treatment process of biochemical method was desirable.%利用自主设计的筛板塔装置模拟吹脱四氯乙烯(PCE)污染废水,综合考察了影响吹脱的各因素(气液体积比、初始浓度和筛板数等),同时对吹脱工艺条件进行了优化,并建立了吹脱模型.研究表明:25.68mg/L PCE废水经吹脱后出水浓度降至0.62mg/L,去除率可达97.59％;气液比对废水的吹脱效果影响很大,且最佳气液比在200左右；PCE初始浓度对去除率的影响并不明显；采用4层塔板时PCE去除效果较好;实验数据很好地遵从一级衰变模型；吨水吹脱成本约为0.31元,可作为后续生化处理的预处理工艺.