IMPROVING THE TREATMENT OF CONTAMINATED AQUIFERS BYDEVELOPING DIRECT-PUSH OXIDAN

在美国，水质是与公众健康相关的最大问题之一。当一个社区得知他们的饮用水被污染时，没有什么比这更能激起公众的强烈抗议了。对美国地下水质量的两个最大威胁是氯化溶剂和石油的污染。目前，美国估计有2万个场所受到氯化溶剂的污染。这些站点中有许多是20到30年前发生的泄漏的残余。如果放任不管，随着时间的推移，与这些泄漏相关的问题的规模和范围只会加剧。同样，含有石油的地下储罐（UST）泄漏是美国地下水污染的主要原因之一。在美国目前受联邦政府监管的59万座UST中，2011年大约有6000座已经确认释放。在过去的十年中，人们一直致力于开发创新的补救技术来对抗这些环境污染物。一种相对成熟的技术是向受污染的含水层注入液体氧化剂或原位化学氧化（ISCO）。成功实施ISCO处理的两个障碍是，当污染物位于低渗透层中，这些较细的结构层不容易接受液体注入，或者当含水层多孔到足以进行液体注入时，但化学氧化剂的内聚性导致密度驱动流动，从而导致氧化剂下沉，无法处理所需的目标层。为了解决这两个问题，AirLift环境公司和内布拉斯加州大学开发了缓释氧化剂-石蜡蜡烛，当插入低渗透区域时，可以缓慢溶解并拦截污染物。为了防止氧化剂从蜡烛向下迁移，开发了气动循环器，在蜡烛底部充气或释放气泡，防止氧化剂下沉，同时大大促进其水平分布。本研究的目的是设计和制造带有曝气器尖端的缓释氧化蜡烛，这种蜡烛可以通过直接推动（即不需要井）插入受污染的含水层。这一发展将使安装缓释氧化剂更容易和更便宜，并大大增加其商业吸引力。拟议的研究将分两个阶段进行，我们将在一个大型地下水流动模型中测试直推式蜡烛的原型。带循环器的直推式蜡烛最有前景，将通过量化氧化蜡烛系统将氧化剂均匀垂直输送至22英尺的能力进行放大和现场测试。现场油井监测。氯化溶剂和石油

DESCRIPTION: Water quality is one of the biggest issues related to public health in the United States. Few situations incite more public outcry than when a community learns that their drinking water has been tainted. Two of the biggest threats to groundwater quality in the U.S. are contamination from either chlorinated solvents or petroleum. Currently, there are an estimated 20,000 sites in the U.S. contaminated with chlorinated solvents. Many of these sites are remnants of releases that occurred 20 to 30 years ago. Left unattended, the size and scope of the problems associated with these spills have only become exacerbated with time. Likewise, leaking underground storage tanks (UST) containing petroleum are one of the leading causes of groundwater contamination in the United States. Of the 590,000 federally-regulated UST currently in the U.S., approximately 6,000 had confirmed releases in 2011. In the past decade, significant efforts have been devoted to developing innovative remedial technologies to combat these environmental contaminants. One technology that is relatively mature is the injection of liquid oxidants into contaminated aquifers or in situ chemical oxidation (ISCO). Two roadblocks to successfully implementing ISCO treatments are when contaminants are located in low permeable layers and these finer textured zones do not readily accept liquid injections or when the aquifer is porous enough for liquid injections, but the cohesive properties of the chemical oxidant results in density-driven flow, thereby causing the oxidant to sink and not treat the desired target zone. To address both problems, AirLift Environmental and the University of Nebraska developed slow- release oxidant-paraffin candles, that when inserted into low permeable zones, slowly dissolve and intercept the contaminant. To prevent the oxidant from migrating downward from the candles, pneumatic circulators were developed that aerate or release bubbles at the base of the candle and prevent the oxidant from sinking while greatly facilitating its horizontal distribution. The objective of this research is to design and manufactue slow-release oxidant candles with aerators tips that can be inserted into contaminated aquifers by direct push (i.e., no wells needed). This development will make it easier and less expensive to install slow-release oxidants and greatly increase its commercial appeal. Proposed research will take place in two stages where prototypes of direct-push candles we be tested in a large groundwater flow model. Direct-push candles with circulators showing the most promise will be scaled up and field tested by quantifying the ability of the oxidant candle system to vertically deliver oxidants evenly to 22-ft. monitoring wells in the field. Chlorinated solvents and petroleum products are clearly among the top groundwater contaminants worldwide. The proposed innovation is specifically designed to provide a cost-effective and efficient technology to combat public water supplies impacted by these contaminants.