场地地下水1,2-二氯乙烷污染的修复实验与数值模拟研究

为筛选适宜的地下水中1,2-DCA(1,2-二氯乙烷)污染的修复方法,本文开展原位修复包括化学氧化清除技术、监测自然衰减技术及其集成技术的有效性研究。首先通过室内实验,研究高铁酸钾和过氧化氢这两种不同氧化剂对1,2-DCA化学清除的效率以及清除过程中对地下水化学环境的影响。结果表明,高铁酸钾和过氧化氢均能有效的进行化学清除工作,且在60 d后对1,2-DCA的去除率都超过了95%。在反应最佳作用时间内,菌落总数会急速下降,随着时间推移和氧化剂的消耗,菌落总数重新大幅度的回升,这表明即使在化学氧化清除效果减弱之后,依旧可以进行自然降解修复。在此基础上,利用野外水文地质资料与水化学监测资料,建立地下水污染修复数值模拟模型,并通过数值模拟结果分析评价监测自然衰减、化学氧化清除和化学氧化-自然衰减三种不同修复技术的可行性及效果差异,为场地地下水有机污染修复技术的筛选提供不可或缺的依据。

Lab Experiments and Numerical Simulations of 1,2-DCA Remediation in Groundwater at Contaminated Sites

This work is to investigate suitable remediation methods for 1,2-DCA (1,2-dichloroethane) contamination in groundwater at contaminated sites, by comparing among the chemical oxidation remediation technique, monitored natural attenuation technique, and their combination. Firstly, the lab experiments were completed using the two different oxidants (potassium ferrate and hydrogen peroxide) to investigate the 1,2-DCA chemical removal efficiency and the effect of the groundwater chemistry environment in the removal process. The experimental results show that both the potassium ferrate and hydrogen peroxide are effective for chemical remediation, and 1,2-DCA removal rate is over 95% after about 60 days. In removing period, the total plate count decreased sharply, and as the oxidants consumed, total plate counts arose to substantial rebound, indicating that after the chemical scavenging effect weakens, bioremediation could be recovered. Then by using the GMS numerical simulation analysis for the contaminated sites, the remediation efficiencies are evaluated for the three different measures including the in-situ chemical oxidation remediation technique, monitored natural attenuation technique, and their combination. The obtained investigation results are expected to bear implications in optimal design and implementation of remediation of groundwater organic contamination at contaminated sites.