Research Opportunity for Undergraduate Students

Research Topics:

1. Bioremediation of Chlorinated Solvent-Contaminated Groundwater

Chlorinated solvents, such as tetrachloroethene (PCE) and trichloroethene (TCE), are prevalent groundwater contaminants. Anaerobic microorganisms such as Dehalococcoides ethenogenes and related species can reductively dechlorinate PCE and TCE completely to the non-chlorinated, non-toxic end product, ethene.  Because Dehalococcoides sp. requires hydrogen (H2), as electron donor, or energy source, to degrade PCE and TCE and many other groundwater organisms may compete with Dehalococcoides for hydrogen, how to deliver hydrogen specifically to Dehalococcoides is an challenging issue in groundwater bioremediation.  It is important to understand the microbial ecology (i.e., how the different microorganisms interact) in order to devise sound bioremediation strategies.

2. Chemical reduction of chlorinated solvents catalyzed by vitamin B12

Studies have shown that vitamin B12, a cobalt cofactor found in Dehalococcoides and many other microorganisms, is the reactive component of the enzymes that catalyze the reductive transformation of chlorinated pollutants including PCE and TCE.  Understanding how B12 reacts with PCE and TCE will help us understand how microbial and enzymatic dechlorination reactions occur and what factors control these reactions.

3. Microbial transformation of chlorinated solvents coupled with anaerobic Fe(0) corrosion

One of the emerging technologies for the remediation solvent-contaminated groundwater is permeable reactive barriers (PRBs), which involves use of reactive materials, such as elemental iron, to remove or degrade contaminants in groundwater in situ. While the chemistry of solvent degradation with Fe(0) has been studied by many, the role of microorganisms in these Fe(0) barriers is not well-understood. A study conducted in our laboratory has shown that anaerobic iron corrosion can support biological transformation of chlorinated ethenes.  Here is a confocal picture of the Fe(0) surface with microbial colonies, taken from a culture-amended sample in which TCE was reduced both chemically by Fe(0) and biologically by the organisms. Since the abiotic and the biological reduction of TCE occur through different routes in the pathway, different products (i.e., non-toxic ethene and ethane vs. toxic vinyl chloride) may form.  Such iron-microbe interactions may have many important implications and applications for site remediateion.

4. Using elemental iron to enhance the degradability of refractory compounds in wastewaters

Elemental iron has been used for groundwater remediation since the mid-1990s.  Although iron has also been shown to transform many compounds commonly found in wastewaters, to date, it has not been applied to wastewater treatment.  Dr. Daniel Cha and I are in the process of developing new wastewater treatment technologies using elemental iron.

5. Graphite-mediate reduction of nitroaromatic pollutants with elemental iron

Cast iron has been used in dozens of permeable reactive barriers (PRBs) to treat groundwater contaminated with chlorinated solvents, heavy metals, radionuclides, and nutrients.  Cast iron contains mostly (~90%) elemental iron and some non-iron components (graphite and other metals).  Most of the studies to date have focused on the transformation of pollutants by elemental iron, whereas the role of the impurities such as graphite remains largely uninvestigated.  We recently found that graphite inclusions in cast iron may control the reaction pathway and products of nitroaromatic pollutants.  This process is critical for designing and modeling groundwater and wastewater treatment processes involving cast iron.  It is also important for accurate prediction of the fate of pollutants.


General chemistry, physics, and calculus

Recommended: organic chemistry and microbiology (or biochemistry)

Students may work for credit, work-study, stipend, or as a volunteer.


Contact Prof. Pei Chiu, Department of Civil & Environmental Engineering, 356C DuPont Hall

Phone: 302-831-3104



(Updated 06/02)