Date of Award

Spring 2022

Project Type

Thesis

Program or Major

Civil Engineering

Degree Name

Master of Science

First Advisor

Nancy E Kinner

Abstract

ABSTRACT

SELECTIVE GRAZING OF INDIGENOUS PROTISTS ON DECHLORINATING BACTERIA IN GROUNDWATER

ByJonathan G. Whaland University of New Hampshire, May 2022

Degradation of trichloroethylene (TCE) in contaminated groundwater can stall at cis-dichloroethylene (cDCE). One cause of the stall could be predation of indigenous protists on the bacteria responsible for cDCE degradation. This research evaluated the uptake and clearance rates of indigenous groundwater protists on KB-1, a bacterial consortium used for bioaugmentation at TCE contaminated sites. The experiments involved two wells, one contaminated with TCE located in Portsmouth, NH and one uncontaminated well located in Newington, NH, and the indigenous protists and bacteria from these wells, as well as the KB-1 consortium. The experiments also studied how sonication affects uptake (UR) and clearance rates (CR) of indigenous protists. Maximum uptake and clearance rates were calculated for the TCE contaminated and uncontaminated wells (URTCE = 0.8 bacteria/protist*h; CRTCE = 0.11nL/protist*h and URControl = 0.04 bacteria/protist*h; CRControl = 0.02 nL /protist h, respectively). These rates are low compared to those reported for protistan predation in other contaminated groundwater. Larger protists (10 µm) from the TCE contaminated well had greater uptake and clearance rates than the smaller protists (2-3 µm) from the uncontaminated well. These rates indicate that indigenous protists are not likely causing the stalls in cDCE observed at the TCE contaminated site.

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