A Novel Method for Biological Perchlorate Reduction Using Elemental Sulfur as an Electron Donor

CBET-0755670 ErgasIntellectual Merit.该项目描述了一种新的方法，完全打破高氯酸盐在污染的地面和地表沃茨无害的产品。我们已经丰富的微生物财团能够耦合元素硫（S）的氧化与高氯酸盐还原。这个稳定的财团不仅成功地降解高氯酸盐使用S 0作为唯一的电子供体，但也做到这一点，在NaCl浓度典型的离子交换（IX）盐水，目前常见的去除technology. Also，我们最近已经分离出一种细菌菌株能够高氯酸盐还原在这个系统中。 初步的上流式填充床生物反应器实验表明，在8小时的空床接触时间下，高氯酸盐从100 ppb降解到4 ppb;然而，高氯酸盐浓度与反应器深度的关系曲线表明，更高的加载速率是可行的。 使用S 0作为电子供体是一种优雅且具有成本效益的生物去除高氯酸盐的方法。元素硫是石油精炼工业的副产品，相对便宜且可用。使用S 0可降低由于有机基质带入配水系统或地下水补给系统而导致的生物不稳定性风险。硫氧化细菌是生长缓慢的自养生物，虽然代谢非常活跃，但产生很少的剩余污泥，减少了反冲洗的需要。硫颗粒可用作简单填充床生物反应器中的介质，或可集成到IX盐水处理和再利用系统或原位可渗透反应屏障（PRB）系统中。 拟议跨学科研究项目的具体目标是（1）调查硫氧化、高氯酸盐还原的条件（包括浓度、盐度、pH、温度和共污染物NO3 -、RDX和HMX），（2）确定参与高氯酸盐还原的主要和活性群落成员，（3）考察了填充床硫磺回收装置的操作条件和性能;用于直接处理生物反应器中的高氯酸盐污染水或高氯酸盐污染的IX盐水的氧化生物反应器。实验将在烧瓶、柱和中试规模。在环境工程和微生物学研究小组之间的紧密联系和良好的相互作用中，我们将使用传统和培养独立的技术来确定微生物联合体的其他成员（例如硫酸盐还原剂和硫氧化剂），并将生物反应器的降解速率与高氯酸盐代谢培养物的遗传潜力进行比较。这些知识将使我们能够在不同条件下的反应堆运行期间跟踪社区的鲁棒性，并开发可用于新系统的种子社区和协议。实验室规模的生物反应器实验将被用来研究废IX再生盐水的处理条件，并检查共污染物对高氯酸盐降解的影响。中试规模的生物反应器实验，在马萨诸塞州的污染场地，将被用来检查高氯酸盐加载速率，操作稳定性，放大，以及成本为典型的水公用事业应用沿着与共污染物的影响。这项研究将扩大对污染含水层系统中自养细菌支持的高氯酸盐还原的理解，并导致新颖且具有成本效益的生物修复解决方案。该项目将提供有关从供水中去除高氯酸盐的可行性的信息，同时尽量减少处理过程中的废物，这项研究还将确定一个与人类活动有关的不寻常的微生物群落。预期的好处包括设计可靠和具有成本效益的生物处理系统，原位PRB和IX系统，可以去除高氯酸盐和回收污染的盐水流的数据。随着高氯酸盐新标准的出台，该项目将成为饮用水设施和军事场所的典范。此外，PI加入了马萨诸塞州大学的核心研究小组，他们正在研究高氯酸盐的发生，毒理学和治疗。该小组将分享设备和专业知识，开发跨学科教育项目，例如研讨会和期刊俱乐部，并在新英格兰组织有关该主题的会议。PI在吸引本科生、初中和高中科学教师以及高中学生参与研究方面拥有良好的记录。我们将与麻省大学工程学院REU项目和我们与教师建立的联系，从波多黎各马亚圭斯大学招募本科生来从事这个项目。我们将开发高氯酸盐模块。

CBET-0755670 ErgasIntellectual Merit. This project describes a novel process to entirely break down perchlorate in contaminated ground and surface waters to innocuous products. We have enriched a microbial consortium capable of coupling elemental sulfur (S0) oxidation with perchlorate reduction. This stable consortium not only successfully degrades perchlorate using S0 as the sole electron donor, but also does this at NaCl concentrations typical of ion exchange (IX) brines, currently a common removal technique.In addition, we have recently isolated a bacterial strain capable of perchlorate reduction in this system. Preliminary upflow packed bed bioreactor experiments show degradation of perchlorate from 100 to 4 ppb at empty bed contact times of eight hours; however, profiles of perchlorate concentration vs. depth in the reactors indicate higher loading rates are feasible. The use of S0 as an electron donor is an elegant and cost-effective method of biological perchlorate removal. Elemental sulfur, a by-product of the petroleum refining industry, is relatively inexpensive and available. Use of S0 reduces the risk of bioinstability due to carry over of organic substrates to water distribution or groundwater recharge systems. Sulfur-oxidizing bacteria are slow growing autotrophs that, although metabolically very active, produce very little excess sludge, reducing the need for backwashing. Sulfur granules can be used as media in simple packed bed bioreactors, or can be integrated into IX brine treatment and reuse systems or in situ permeable reactive barrier (PRB) systems. Specific objectives of the proposed interdisciplinary research project are (1) to investigate conditions for sulfur-oxidizing, perchlorate-reduction (including concentration, salinity, pH, temperature, and cocontaminants NO3 -, RDX, and HMX), (2) to determine dominant and active community members involved in perchlorate reduction, (3) to investigate operating conditions and performance of packed bed sulfur-oxidizing bioreactors for direct treatment of perchlorate contaminated water in bioreactors or perchlorate contaminated IX brines.Experiments will be carried out at flask, column and pilot scale. In a closely knit and well established interaction between environmental engineering and microbiology research groups, we will identify additional members of the microbial consortium (e.g. sulfate-reducers and sulfur-oxidizers) using both traditional and culture independent techniques, and compare bioreactor degradation rates to the genetic potential of the perchlorate-metabolizing culture. This knowledge will allow us to follow community robustness during reactor operation under varying conditions, and to develop a seed community andprotocols that can be used in new systems. Bench-scale bioreactor experiments will be used to investigate conditions for treatment of spent IX regenerant brines and to examine the effect of co-contaminants on perchlorate degradation. Pilot-scale bioreactor experiments, at a contaminated site in Massachusetts, will be used to examine perchlorate loading rates, operational stability, scale-up, and costs for typical water utility applications along with co-contaminant effects. This research will expand the understanding of perchlorate reduction supported by autotrophic bacteria in contaminated aquifer systems and lead to novel and cost-effective bioremediation solutions.The broader impacts of this research are varied and far-reaching. The project will provide information on the feasibility of removing perchlorate from water supplies while minimizing disposal of process wastes.This study will also define an unusual microbial community relevant to human activities. Anticipated benefits include data for design of reliable and cost-effective biological treatment systems, in situ PRBs, and IX systems that can remove perchlorate and recycle contaminated brine streams. With upcoming new standards for perchlorate this project will serve as a model for drinking water utilities and military sites.In addition, the PIs join a core group of researchers at the University of Massachusetts who are studying the occurrence, toxicology, and treatment of perchlorate. This group will share equipment and expertise, develop interdisciplinary educational programs, such as seminars and journal clubs, and organize conferences on this topic in New England.The PIs have an excellent track record in engaging undergraduates, middle and high school science teachers, and high school students in research. We will work with the UMass College of Engineering REU program and our established connections with faculty to recruit undergraduates from the University of Puerto Rico Mayaguez to work on this project. We will develop modules on perchlorate.