Bioremediation of subsurface oil in a tidally-influenced sand beach: Impact of hydraulics and interaction with pore water chemistry Xiaolong (Leo) Geng, PhD Center for Natural Resources Development and Protection Department of Civil and Environmental Engineering New Jersey Institute of Technology

Co-authors Funding Michel C. Boufadel, NJIT Kenneth Lee, Commonwealth Scientific and Industrial Research Organization (CSIRO) Stewart Abrams, Langan Engineering Inc. Funding National Oceanic and Atmospheric Administration National Science Foundation Department of Fisheries and Oceans, Canada

Oil biodegradation in the intertidal zone of a beach in the GOM

Oil biodegradation in the unsaturated zone mi

BIOB model description BIOB (BIO-Batch) is a numerical model to simulate the aerobic hydrocarbon biodegradation in porous media in a given volume. Oil biodegradation Hydrocarbon Hydrocarbon degrader mi Term Function: Biodegradation Physical removal Biodegradation Physical removal

Continued Monod kinetics Oxygen consumption Limiting factors: Field capacity Substrate Nutrient Oxygen Oxygen consumption mi Geng, X., Boufadel, et. al., 2013, Biodegradation, 24 (2): 153-163. Geng, X. Boufadel, et al., 2014. Marine Pollution Bulletin, 83 (1), 138-147. Torlapati and Boufadel, 2014, Frontiers in Microbiology, 5, 212.

Aromatics Can you make the axes titles and numbers larger? mi

Aromatic Degraders Can you make the axes titles larger? mi

Oxygen Consumption mi

Water flow and solute transport in beaches MARUN (MARine Unsaturated) Model Two-dimensional finite element model MARUN (Boufadel et al. 1999) Considers water flow below and above the water table Accounts for water salinity on water density and viscosity. Boufadel, et al., Journal of Contaminant Hydrology, 1999, 37(1): 1-20. Boufadel, et al., Water Resources Research, 2000, 36(9): 2549-2565. Boufadel and Xia, Environmental modeling and software, 2011, 26(7): 899-912.

MARUN validation: Tide Li and Boufadel, NATURE Geoscience, 2010, 3(2): 96-99. Guo et al., Journal of Geophysical Research, Oceans, 115, C12077, 2010. Xia, et al., Water Resources Research, Vol. 46, W10528, 17p, 2010.

MARUN Validation: Waves Geng, X. et al., 2014. Journal of Contaminant Hydrology, 165: 37-52. Geng, X., Boufadel, M.C., 2015. Journal of Geophysical Research: Oceans. doi: 10.1002/2014JC010539.

BIOMARUN model description MARUN + BIOB = BIOMARUN Eight equations: subsurface water flow, fates of dissolved salts, two types of substrate (i.e., hydrocarbon), two types of degraders, dissolved oxygen, and nutrient (nitrogen) Oil is attached in the beach Oxygen is replenished from atmosphere, inland and sea Nutrient (i.e., nitrogen) is replenished from inland and sea Indigenous microorganisms are assumed present mi

Simulation Conditions 100 mg/kg sediment for long-chain alkanes and 50 mg/kg sediment for aromatics Concentration of dissolved oxygen is 8.2 mg/L from inland and sea Background conc for alkane degraders is 6×10-2 mg/kg Background conc for aromatic degraders is 6×10-4 mg/kg High tide= 3.95 m Low tide=3.35 m Inland WT = 3.75 m 1.2 mg-N/L 0.2 mg-N/L

Oxygen distribution

Nitrogen distribution

Beach-wise variation using BIOMARUN

Intertidal zone oil biodegradation Shallow location You could zoom in more on the intertidal zone of the beach. You could put the x axis at the level of the low tide line. Deep location

Mid intertidal zone

Bioremediation Figure: Alkane biodegradation at different application rate Figure: Alkane biodegradation at different application duration. Figure: Biochemical residence time map (BRTM) in the beach at Cthreshold = 2.0 mg-N/L

Conclusion The aerobic biodegradation of oil in tidally influenced beaches was investigated in this work using realistic beach and tide conditions. Simulation resulted uneven oil biodegradation. In the upper intertidal zone, where the inland incoming nutrient concentration is large (1.2 mg/L), oil biodegradation occurred deeper in the beach in comparison with shallow zones. In the mid-intertidal zone, a reversal was noted where the biodegradation was fast at shallow locations in comparison with deep locations. Oxygen concentration in the mid-intertidal zone exhibited two peaks as function of time. One peak was associated with the high tide, and a second oxygen peak was due to replenishment of the pore by oxygen from the atmosphere.

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