Enhancing oleophilic biobarriers for non-tidal sediments impacted with petroleum hydrocarbons
Date
2021
Authors
DeBiasi, Marina Ann, author
Scalia, Joseph, IV, advisor
Sale, Tom, advisor
Sutton, Sally, committee member
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Abstract
The objective of this study is to develop tools to prevent petroleum hydrocarbons trapped in non-tidal sediments from causing detrimental effects such as sheens. Oleophilic biobarriers (OBBs) provide a robust, low-cost solution for managing petroleum hydrocarbon contamination at groundwater-surface water interfaces in tidal zones but are untested in non-tidal zones. This study evaluates enhanced OBB remedies for petroleum hydrocarbon contamination in non-tidal zones by incorporating amendments within the OBB. The amended OBB is intended to serve as an engineered bioremediation tool to enhance microbial growth and degradation of petroleum hydrocarbons by supplying the system with a resource of electron donors and nutrients while simultaneously mitigating petroleum hydrocarbon releases to surface water. Complementary laboratory and field studies were conducted to test non-tidal OBBs (NOBBs) with six amendment types: (1) hematite (H), (2) greensand (GS), (3) greensand + hematite (GS+H), (4) gypsum (GYP), (5) hematite + greensand + gypsum (ALL), and (6) blank (B). The laboratory study was constructed as a series of chemostats using sediment and water samples from the field site. This study observed the productivity of petroleum hydrocarbon degradation through biweekly headwater extractions analyzing alkalinity, dissolved inorganic carbon (DIC), and pH as well as continuously monitored oxidation reduction potential (ORP). Results from these tests indicated that the GYP amendment was most effective in degrading petroleum hydrocarbons while the B and ALL amendments were least effective. However, all systems exhibited increased effluent DIC characteristic of enhanced petroleum hydrocarbon degradation. The field study was constructed as a series of OBB disks deployed atop petroleum hydrocarbon impacted sediments in a non-tidal setting. Results from the laboratory and field study illustrated abundant microbial growth after six months. The NOBBs with the top three highest numbers of microbial abundance were found in the field (F): F-GS+H, F-B, and F-GS. The overall results of both lab and field studies suggest that NOBBs, whether amended or not, provide effective media for petroleum hydrocarbon-degrading microorganisms. This study illustrates the promise of the non-tidal OBB as a bioreactive barrier for petroleum hydrocarbon impacted sediments. Further study is needed to evaluate the rate of petroleum hydrocarbon degradation in a non-tidal OBB relative to the rate of loading.
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Subject
bioreactive
contaminant
sheen
bioremediation
biodegradation
petroleum hydrocarbon