Institute: North Dakota
Year Established: 2015 Start Date: 2015-03-01 End Date: 2016-02-29
Total Federal Funds: $4,800 Total Non-Federal Funds: $9,600
Principal Investigators: Achintya Bezbaruah
Abstract: Trichloroethylene (TCE) is a widely used organic solvent for electronic, metal finishing, machinery, and dry cleaning application. As a result of improper waste disposal practices, TCE has become one of the most problematic classes of volatile organic compounds found in groundwater. Numerous studies have reported that the widespread presence of TCE in groundwater is a serious public concern due to the hazardous nature of this contaminant. The maximum contaminant level (MCL) for TCE in drinking water is 5 L. TCE has the ability to penetrate deep into the aquifer much below the water table as a dense non-aqueous-phase liquid (DNAPL). TCE can destroy the structure of clayey minerals, making them more permeable to dissolved contaminants. Trichloroethylene (TCE) has been found in at least 60% or 861 of the NPL (National Priorities List or Superfund) sites and there are tens of thousands of other cleanup sites across the country. Sheyenne River at Valley City, North Dakota, has TCE levels beyond the acceptable limits (5g/L) as prescribed by USEPA. A huge contaminated site was found in West Fargo, ND. A survey conducted in 2010 in Valley City on 6826 people who consumed water contaminated with TCE revealed four out of six people have some sort of health impairment. The use of non-zero valent iron (NZVI) for the treatment of contaminated soil and groundwater is increasing. NZVI can treat contaminant plumes and the source significantly because of their high surface area to volume ratio, rapid kinetics, and high reactivity. Polysaccharides are promising biopolymers for coating NZVI particles as they can increase colloidal stability of NZVI. Starch is one of the cheaper and greener polysaccharides compared to other dispersants. Starch stabilized bimetallic iron nanoparticles can significantly increase the degradation rate of TCE. To improve functionality, native starches can be modified by chemical, physical or enzymatic process. Modified starch containing carboxyls is ideal for coating NZVI because carboxyls have an affinity to bind with the surface of iron oxides. It is proposed in this study to prepare a novel polymer for coating NZVI for using in PRBs as a reactive material to remove TCE, a very toxic contaminant. Objectives of this study are: To prepare a novel polymer, which will not only be cost effective but also environmentally friendly, To Use this polymer to coat NZVI to increase their sticking coefficient in aquifer, To conduct two dimensional transport study to determine if coated NZVI particles could be the potential candidates for creating permeable reactive barriers (PRBs) in the subsurface at different flow velocities and different porosity, To evaluate TCE degradation using both bare NZVI and CNZVI (coated NZVI) particles, and To evaluate the efficiency of CNZVI as a reactive material in PRB for TCE removal. The technique can be applied in both surface and groundwater remediation. This type of system is very suitable for in-situ groundwater remediation. As there are a number of TCE contaminated sites in the state, the research results will benefit North Dakota.