Abstracts

178 - Simulation of Persulfate Oxidation Coupled with Enhanced
Bioremediation as an Emerging Remediation Strategy for
Petroleum Impacted Sites
Mahsa Shayan, Neil R. Thomson & James F. Barker
University of Waterloo, Waterloo, Ontario, Canada
John Molson
Department of Geology and Geological Engineering, Université Laval, Québec City, Québec,
Canada
Groundwater contamination by petroleum hydrocarbon (PHC) compounds, including
the high impact, toxic and persistent monoaromatic compounds such as benzene, toluene,
ethylbenzene and xylene (BTEX) poses a serious risk to human health and the environment.
Innovative and efficient remediation strategies are required to mitigate such risks in
a smart, and cost and time effective manner. The coupling or sequential use of different
remediation technologies, also referred to as a “treatment train”, is an emerging remediation
strategy that combines the strengths of each individual remediation technology to
improve the overall treatment efficiency and minimize clean-up cost and time. Coupling
in situ chemical oxidation (ISCO) and enhanced bioremediation (EBR) is an example of a
plausible treatment train for the application at PHC-contaminated sites.
Persulfate (S 2
O 8
2-
) is a persistent but yet aggressive oxidant that has been successfully applied
for the treatment of PHC-contaminated sites, and it also has a significant inherent
advantage in the context of being an integral part in an ISCO/EBR treatment train. The
reaction of persulfate with organic compounds leads to the production of sulfate, which
along with the breakdown of complex organic compounds into simpler and more bioavailable
organic substrates, can lead to enhanced biodegradation activity of a group of
microorganisms known as sulfate reducing bacteria (SRB). Subsequently, the enhanced
bioremediation under sulfate reducing conditions is expected to dominate the removal of
the remaining contaminant mass following persulfate treatment.
The effectiveness of a persulfate/EBR treatment train is dependent on the delivery and mixing
of persulfate and sulfate in situ. Application of a modelling tool capable of simulating the intertwined
physical, chemical and biological processes involved in a persulfate/EBR treatment train
is useful to understand the influence of the key processes (e.g., flow and transport, reaction kinetics,
design parameters) on treatment effectiveness. To date, there has been no reported effort
made to simulate a persulfate-based ISCO treatment system or an ISCO/EBR treatment train.
In this study, a modelling tool (BIONAPL/PS) was developed to simulate the coupled
processes involved in a persulfate/EBR treatment train and to quantify the impact of various
parameters on the performance of this treatment system. The key processes captured
in this model include transient groundwater flow, multi-component advective-dispersive
transport, persulfate decomposition, chemical oxidation of dissolved PHCs, and biodegradation
under various redox conditions. The model also simulates the inhibitory impact
of persulfate on subsequent sulfate reduction. The formulation of BIONAPL/PS was validated
against an analytical solution, and observations from a series of laboratory column
IAH-CNC 2015 WATERLOO CONFERENCE
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