LNAPL多相抽除法對BTEX移除效能提升之探討

Abstract

計畫名稱：LNAPL多相抽除法對BTEX移除效能提升之探討

油品污染場址之整治中，若該場址地下水位面上有浮油的存在，則首要工作即為浮油 回收(Free product recovery)以移除污染源（Source removal)。浮油回收的模擬在過去使 用的程式僅考慮雙相流或三相流，僅將LNAPL視為單一液體。換言之，雖然汽油、柴 油、飛機燃料油都是混合物，但在模擬中都僅視為單一流體，賦予單一性質，其密度、 黏滯性、介面張力等都個別僅以一個參數計算。實際上，油品污染場址的整體控制或 整治效果，其核心還是地下水中的BTEX。油品中除了 BTEX與MTBE幾種有危害性 成分以外，其他的成分毒性甚小、溶解度低且較易被生物降解，對地下環境的影響較 小。本研究將利用TMVOC軟體模擬近年來油品污染整治場址常用之多相抽除法 (Multi-phase Extraction, MPE)，因TMVOC中的LNAPL相可分別將油品中的各種成分 包括BTEX與MTBE精確地模擬，故可藉以更深入瞭解在多相抽除過程中，除了浮油 回收以外，BTEX與MTBE從非飽和層與浮油中移除的狀況，以及在浮油回收過程中 對BTEX與MTBE溶解至地下水抑制的效率與回收效率。透過不同回收井間距與負壓 之配置，以及將地下水位同時洩降納入，藉BTEX回收與溶解至地下水中的總量找出 提升MPE之方式。

計晝名稱：Assessment of Removal Rate Enhancement of BTEX by Multi-Phase Extraction of LNAPLs

In remediation of LNAPL contaminated sites, free product recovery is the major tool for source removal when there is a LNAPL layer on top of the groundwater table. In the past, the modeling of free product recovery consider LNAPL phase as a single fluid without discriminating its components including BTEX and MTBE. However, the dissolution and control of BTEX and MTBE are the most critical issue of an LNAPL contaminated site, all other components of LNAPL are less toxic, less soluble in water, and easily biodegraded. The objective of this proposed research is to use TMVOC, which can take the multiple component of LNAPL especially BTEX and MTBE into account, to simulate the multi-phase extraction and assess the relative effectiveness of free product recovery and soil vapor extraction to control the release rate into groundwater and recovery rate of BTEX and MTBE. The removal of BTEX under various layout and vacuum of MPE wells, as well as incorporating groundwater pumping, will be evaluated for determination of best scheme for enhancement of remediation effectiveness.