Following synthesis of the respective disciplines, participants regrouped to brainstorm and envision the range of potential applications the control of bio-soils processes could be used for. In each group there was at least one representative from the disciplines of geotechnical engineering, environmental engineering, geochemistry and biogeochemistry, microbiology and biology, and agriculture and soil science. Five groups were formed to explore the following potential application/impact areas:
Each group was charged to identify specific potential applications, the critical state variables for the general application, the primary questions that must be answered, the measurement and monitoring requirements, and other relevant issues. As expected given the creative level of this exercise, the results from each group differed somewhat in format.
As evident below, specific and significant opportunities in each application area and the primary hard science and engineering research required to accomplish them were identified. A summary of each application group’s ideas follows:
Mechanical Control
Applications:
Infrastructure
Geological Hazard and Mitigation
Global Warming Issues
State Variables
Strength
Stiffness
Volume Change Properties
Hydraulic Conductivity
Durability
Process Control Variables: Chem and Bio, Pressure and Temperature
Hard Science: How to control soil as bio reactor
Understand and Model biological and chemical processes in soil and their impacts on the micro structural features
Understand the impact of the micro structural features on the Physical Properties
Characterization of the system, including heterogeneity
Control subsurface-environment (pH, simulate procedures), growth, propagation of the processes
Hard Engineering
Bridge scale gap to translate micro to macro and macro to micro
Macroscopic explained by microscopic science
Heterogeneity/Variability
Measurements and Monitoring
Site characterization; process monitoring; long term behavior
Tools:
geophysics: tomographic methods
geochemistry: ground water and pore water chemistry
geomicrobiology: presence, activity, and abundance
Need to improve resolution of existing tools, sensors, and models
To significantly increase the level of carbon sequestration.
Can we engineer the system such that microbes will nucleate CaCO3 into a granular mass?
Engineer a way to matrix the soils to transfer carbon into a more reduced, deeper environment
Nuclear Power
A GHG-free power source- zero carbon emission
Hard Science Questions
What are the controls on the transfer of reduced organic carbon into mineral carbon- hydrology, precipitation, etc.?
How can we manipulate these processes such that we can tip the balance into a carbonate precipitate.
What limits the turnover, and what is the availability of calcium?
What are the metal delivery systems that may accelerate the process of carbon capture
Can we get a handle on the microbial/geomicrobial chemical processes in action
What availability of biomass near the subsurface is there for us to use?
Evaluation of the kinetic controls of the system
What can we do to the natural pedogenic functions to allow us to capture CO2?
Can we stabilise the reduced C such that when it re-oxidises, it goes into deeper reservoirs rather than being released back into the atmosphere.
What is the process and mechanism that transfers or pumps down the captured carbon (from atmosphere through photosynthesis), converts it to organic carbon and moves to a depth where it is mineralised.
Need to research the link between top metre and solid bedrock in terms of biogeochemical processes
Monitoring and Measurements
Scale Concerns: Monitor small changes in the flux in the shallow soils- would be very small compared with the natural C fluxes in and out of the soil
Engineered watersheds for clean water; infiltration control for landfill applications; control of heat island performance; crime reduction; multi-functional control; integrated landscape design
