The pump-and-treat (P&T) method is a common remediation approach that is used to mitigate occurrences of hydrocarbon contamination. In a well-studied site that had been contaminated by a large volume of jet fuel, continuous monitoring of the water table and floating phase thickness revealed the most significant process governing the effectiveness of the site’s active remediation system. The floating phase thickness recorded in the wells monitored varied greatly (> 0.50 m) and was negatively correlated with the water table level. Although the dependence of light non-aqueous phase liquid (LNAPL) thickness on water table fluctuations is widely recognized, LNAPL recovery, which is governed by alternating cycles of LNAPL release and entrapment in pore spaces, has been poorly described. Thus, we present a specific case in which LNAPL recovery is expected only episodically, when the water table falls sufficiently. In the period spanning from 2006 to 2008, LNAPL remediation recovered nearly 180 m³ of oil. In later years, the volume of recovered LNAPL declined and ceased between 2010 and 2014, when the water table rose. Importantly, our research demonstrates that the P&T remediation approach is solely effective during a period of 4 months in dry years. Thus, cleanup methods and contaminated site management strategies should be reconsidered.

抽水处理（P＆T）方法是一种常见的补救方法，用于减轻碳氢化合物污染的发生。在一个经过充分研究的站点中，该站点已被大量的喷气燃料污染，对地下水位和浮相厚度的连续监控显示出控制该站点的主动修复系统有效性的最重要过程。监测井中记录的浮相厚度变化很大（> 0.50 m），并且与地下水位呈负相关。尽管人们广泛认识到轻质非水相液体（LNAPL）的厚度对地下水位波动的依赖性，但对LNAPL的回收率（由LNAPL释放和滞留在孔隙中的交替循环决定）的描述却很少。从而，我们提出了一个特殊的情况，即当地下水位充分下降时，仅在一般情况下才会预期LNAPL恢复。从2006年到2008年，LNAPL修复恢复了将近1.8亿³ 油。在随后的几年中，当地下水位上升时，2010年至2014年之间，回收的LNAPL的数量下降并停止。重要的是，我们的研究表明，P＆T补救方法仅在干旱年份的4个月内有效。因此，应重新考虑清理方法和受污染的场地管理策略。