Travel-time based model of bioremediation using circulation wells

Area of Science:

• Environmental Science
• Geochemistry
• Microbiology

Background:

• Vertical circulation wells enhance bioremediation by supplying microorganisms with necessary substrates.
• Understanding bioreactive transport in complex flow fields is crucial for effective in-situ remediation.
• Trichloroethene (TCE) is a common groundwater contaminant requiring efficient degradation methods.

Purpose of the Study:

• To develop and present a travel-time based modeling approach for bioreactive transport in circulation well systems.
• To simulate the cometabolic dechlorination of TCE using alternate oxygen and toluene injections.
• To optimize injection strategies to stimulate microbial activity and minimize aquifer biofouling.

Main Methods:

• Modeling bioreactive transport using a travel-time based approach in a flow field generated by circulation wells.
• Simplifying transport to a one-dimensional problem by neglecting local dispersion and considering sorption behavior.
• Applying the model to simulate alternate injection of oxygen and toluene for TCE bioremediation.

Main Results:

• The model characterizes recirculation by discharge densities over travel time.
• Simulations show that sufficient breaks between oxygen and toluene pulses minimize mixing within wells.
• The proposed injection scheme effectively stimulates biomass growth for bioremediation.

Conclusions:

• A travel-time based model provides an efficient method for simulating bioreactive transport in circulation well systems.
• Optimized injection strategies can enhance the cometabolic dechlorination of TCE.
• This approach allows for stimulated biomass growth without the risk of aquifer biofouling, paving the way for improved bioremediation techniques.