Master of Science in Engineering (MSE)
Civil and Environmental Engineering and Construction
First Committee Member
Second Committee Member
Third Committee Member
Fourth Committee Member
Number of Pages
Remediation of contaminated groundwater is becoming increasingly more
important as much of the U.S. population relies on groundwater for their drinking water.
Contaminates such as Chromium, common pollutant at industrial waste sites, and
Hexavalent chromium which is toxic to humans, animals, and plants are major
concerns. Chlorate, another contaminate of concern, has been widely detected in
ground and surface water in the United States and even locally in Henderson Nevada at
the Nevada Environmental Response Trust (NERT) sites. To assist in mitigating this
issue, this research focuses on the removal of high levels of hexavalent chromium (ppm
range) (Cr(VI)) and chlorate (ClO3-) from water using zero valent iron (ZVI).
Zero valent iron is a proven technology for the biotic and abiotic reduction of a
wide variety of environmental contaminants including Cr(VI), nitrate (NO3-), chlorinated
organic compounds, arsenic, ClO3-, and ClO4-. There is a lack of research investigating
the reduction of Cr(VI) using ZVI+Sludge, specifically examining how competing
contaminants, such as chlorate, would affect Cr(VI) remediation. The overall goal of this
research was to determine whether a combination of ZVI+Sludge can improve reduction
kinetics of degradation of high levels of Cr(VI) and chlorate, when they occur together.
A series of batch tests were conducted in which a synthetic groundwater,
containing the contaminants of interest, was added with various concentrations of ZVI,
microbial seed, and an external carbon source (i.e. EOS emulsified oil). Depending on
the method to be tested, varying concentrations of ZVI, Sludge, or a combination of
ZVI+Sludge were added to the vials. Degradation experiments were performed first with
single contaminants followed with the contaminants together. The analysis of the
experiments related to ZVI+Sludge showed a statistically significant increase in the
reduction of Cr(VI) alone over ZVI. The outcome of this research suggests an increase
in contaminant reduction rates when combining chemical and biological treatment
(ZVI+Sludge). Supporting the conclusion that a ZVI+Sludge treatment method could
reduce the amount of ZVI material required and/or increase the longevity of the system.
Batch test; Bio-ZVI; Chlorate; Groundwater; Hexavalent chromium; Zero valent iron
Greenhalgh, Kenneth R., "Comparison of Zero Valent Iron (ZVI) and ZVI+Sludge for the Removal of High Levels of Hexavalent Chromium and Chlorate from Waters" (2019). UNLV Theses, Dissertations, Professional Papers, and Capstones. 3606.