摘要
某电子机械厂搬迁后原址约1 500 m区域地下水受到了多种类型的有机物复合污染,包括石油烃、苯系物和多环芳烃,并且部分区域发现有明显轻质非水溶相流体(LNAPL)。该案例首先应用多相抽提技术强化回收地下水中的LNAPL,并去除土壤气体和地下水中溶解态的污染物。当地下水中不存在明显LNAPL且污染物浓度不再明显降低后,继续应用原位化学氧化技术进行修复,所使用氧化剂为"过硫酸钠+Na OH"。经过45 d的多相抽提以及4t过硫酸盐氧化剂注射之后,验收监测表明污染区域地下水污染物浓度均达到了修复目标。该案例表明,多种修复技术的联合应用能够明显加快修复进度、提高修复效率、节约修复成本。对于存在LNAPL,且修复目标较严格的有机复合污染场地,多相抽提结合原位化学氧化联合修复是一种较好的修复技术选择。
Subsurface groundwater with an area of approximate 1500 m^2 at a former electric machinery plant was contaminatedby m ulti-organic compounds including total petroleum hydrocarbons （TPH）, BTEX and polycyclic aromatic hydrocarbons. Lightnon-aqueous phase liquid （LNAPL） was observed clearly at some locations within the remediation area. In this case, multi-phaseextraction （MPE） was firstly applied for recovery of LNAPL floating on the groundwater, extraction of soil gas containingcontaminants, and pumping of groundwater containing dissolved compounds. MPE system was kept in operation until to the extentthat no obvious LNAPL was noted and the contamination levels decreased to be stable in groundwater. In situ chemical oxidation（ISCO） was subsequently applied to further reduce the concentration levels of contaminants to meet the stringent remediation values,with “persulfate＋NaOH” as oxidant. Following 45-day operation of MPE and injection of 4 tons of persulfate into the subsurface,the monitoring data showed that all target contaminants in the groundwater met the remediation values. This case indicated thatcombined application of multiple remediation technologies could significantly shorten the remediation period, raise the remediationefficiency and save the remediation cost. For the contaminated site where LNAPL was observed to be present and the remediationvalue was set to be stringent, combined application of MPE and ISCO was a competitive candidate remediation technology.
出处
《环境保护科学》
CAS
2016年第3期154-158,共5页
Environmental Protection Science
