Internet of things monitoring of the oxidation reduction potential in an oleophilic bio-barrier
Date
2020
Authors
Hogan, Wesley W., author
Scalia, Joseph, advisor
Sale, Thomas, advisor
Ham, Jay, committee member
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Volume Title
Abstract
Petroleum hydrocarbons discharged to surface water at a groundwater-surface water interface (GSI) resulting in violations of the Clean Water Act often spark costly cleanup efforts. The oleophilic bio-barrier (OBB) has been shown to be effective in catching and retaining oils via an oleophilic (oil-loving) geocomposite and facilitating biodegradation through cyclic delivery of oxygen and nutrients via tidally driven water level fluctuations. Conventional resistive (e.g., geomembrane) or absorptive-only (e.g., organoclay) barriers for oil at GSIs limit oxygen diffusion into underlying sediments and are susceptible to overloading and bypass. Conversely, OBBs are designed to function as sustainable oil-degrading bioreactors. For an OBB to be effective, the barrier must maintain aerobic conditions created by tidally driven oxygen delivery. Oxidation reduction potential (ORP) sensors were installed within an OBB in the northeastern US with an internet of things (IoT) monitoring system to either confirm the sustained oxidizing conditions within the OBB, or to detect a problem within the OBB and trigger additional remedial action. Real-time ORP data revealed consistently aerobic oxidation-reduction (redox) conditions within the OBB with periods of slightly less oxidized redox conditions in response to precipitation. By interpreting ORP data in real time, we were able to verify that the OBB maintained the oxidizing conditions critical to the barrier functioning as an effective aerobic bioreactor to degrade potentially-sheen generating oils at GSIs. In addition, alternative oleophilic materials were tested to increase the range of candidate materials that may function as the oleophilic component of an OBB. Materials tested included thin black (232 g/m2), thin white (244 g/m2), medium black (380 g/m2), and thick black (1055 g/m2) geotextiles, as well as a coconut fiber coir mat. Finally, a model was developed to estimate the required sorptive capacity of the oleophilic component of an OBB based on site-specific conditions, which can be used to inform OBB design.
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Subject
IoT
oil
petroleum
OBB
biodegradation
ORP