BTEX Contaminated Groundwater Remediation by Bio-Electrochemical Systems

描述（由申请人提供）：从地下储罐（UST）泄漏石油是美国地下水质量的最大威胁之一。目前，美国约有215，000个站点，约有597，000个联邦监管的活跃UST。据估计，在未来几十年内，根据联邦法规，预计将有680，000个UST需要补救，平均清理成本接近每个站点125，000美元。泄漏UST占美国土壤和地下水修复市场的40%以上，后者在2004年的收入约为81亿美元，预计到2010年市场将达到130亿美元。苯系物（苯、甲苯、二甲苯和二甲苯）是地下水中常见的芳香族化合物。BTEX被美国环境保护署（EPA）列为优先污染物，是EPA 33 - 50计划的目标化合物之一。苯在ATSDR 2011年物质优先列表中排名第6。苯具有致畸性，可能与白血病的发生有关，甲苯是中枢神经系统的可疑有害物质。由于这些健康问题，苯、甲苯、乙苯和二甲苯在饮用水中的最大含量分别为百万分之0.05、1、0.7和10。在处理BTEX污染地下水的所有修复技术中，生物修复似乎是一种经济、节能和环境友好的方法。然而，通常需要额外的电子受体来加速该过程。好氧修复被认为是最快的方法，但通常会导致挥发性有机化合物损失到空气中，而不是完全去除BTEX，这与氧气注入系统的高资本和运营成本有关。厌氧过程的生物降解效率有限，通常需要添加硝酸盐或 硫酸盐作为电子受体，这显著增加了总成本。该项目提出在新型生物电化学系统（BES）中去除地下水中的BTEX，同时产生甲烷。该技术的益处是：（i）由于生物电化学刺激和改进而更有效;（ii）由于缺乏额外的电子受体而更具成本效益;（iii）由于大多数碳被捕获为甲烷而更具可持续性。第一阶段将侧重于展示BTEX在BES中的生物降解。第二阶段将进行系统优化、规模化和试点示范。第一阶段和第二阶段研发的最终目标将是一个BTEX污染的地下水修复系统，该系统：（i）具有高处理效率;（ii）具有较低的成本;（iii）通过结合电化学信号的强大系统;（vi）碳足迹显著较小的绿色修复技术。

DESCRIPTION (provided by applicant): Leaking petroleum from underground storage tanks (USTs) is one of the biggest threats to groundwater quality in the US. Currently, there are approximately 597,000 federally-regulated active USTs at about 215,000 sites in the US. It was estimated that 680,000 USTs are expected to require remediation under federal regulations over the next few decades, with average cleanup costs reaching almost $125,000 per site. Leaking USTs account for over 40% of US soil and groundwater remediation market, the latter posted revenues of about $8.1 billion in 2004 and an estimated market of $13 billion by 2010. BTEX (benzene, toluene, ethylbenzene and xylenes) are the major aromatic components frequently found in groundwater as a result of leak in USTs. BTEX are classified as priority pollutants regulated by the US Environmental Protection Agency (EPA) and were among the target compounds toward EPA's 33-50 program. Benzene is also ranked #6 in the ATSDR 2011 Substance Priority List. Benzene is teratogenic and may be associated with the development of leukemia, and toluene is a suspected depressant of central nervous system. Because of these health concerns, the maximum levels in potable water are 0.05, 1, 0.7 and 10 ppm for benzene, toluene, ethybenzene and xylenes, respectively. Among all remediation technologies for treating BTEX-contaminated groundwater, bioremediation appears to be an economical, energy-efficient and environmentally sound approach. However, additional electron acceptor is usually required to accelerate the process. Aerobic remediation is regarded as the fastest process but usually leads to loss of volatile organic compounds into air instead of complete BTEX removal associated with high capital and operational cost due to the oxygen injection system. Anaerobic process is limited in biodegradation efficiency and usually requires addition of either nitrates or sulfates as electron acceptors which significantly increase the total cost. This project proposes to remove BTEX from groundwater in a novel bio-electrochemical system (BES) while simultaneously generating methane. The benefits of this technology are: (i) more efficient due to bio- electrochemical stimulation and improvement; (ii) more cost effective due to lack of additional electron acceptor; (iii) more sustainable as most carbon is captured as methane. Phase I will focus on demonstrating biodegradation of BTEX in BES. Phase II will work on system optimization, scale up and pilot demonstration. The end goal for Phase I and Phase II R&D will be a BTEX contaminated groundwater remediation system that is: (i) with high treatment efficiency; (ii) with lower cost; (iii) robust system by incorporating electrochemical signals; (vi) green remediation technology with significantly smaller carbon footprint.