Biosolids Management Technology
GeoEnvironment Technologies has developed, patented, and successfully demonstrated an innovative new technology to manage municipal sludge with significant environmental benefits. We call this technique Deep Earth Digestion / Sequestration. Through appropriate geological formation selection, well design, and advanced geophysical monitoring, the biosolids slurry can be injected into soft, porous, sand formations in the deep subsurface (on the order of 5000ft or more).
Deep underground the earth’s natural geothermal heat sterilizes the biomass quickly (within 24 hours), and then through continuing anaerobic biodegradation converts the organic mass to methane and carbon dioxide. The carbon dioxide is preferentially absorbed by formation waters (due to its high solubility in water) while relatively pure methane collects and may be stored long-term, or eventually produced for beneficial use.
- Inject municipal sludge into deep geologic formations (5000 ft)
- Allow material to undergo natural process of high-temperature anaerobic biodegradation, instantly (within 24 hrs) sterilizing the material and over time (30-60 days) starting conversion to methane and carbon dioxide
- Design process to capture and sequester generated CO2 in formation water
- Store or recover high purity methane for beneficial use
At the high temperature and pressure conditions in the deep subsurface, carbon dioxide is ten times more soluble in water than methane. Therefore, as the gas percolates through the formation water, the carbon dioxide will be preferentially absorbed by the water, leaving a relatively methane rich gas phase. Due to density segregation, the gas will percolate upwards through the brine filled porous sand formation until it reaches the impermeable capping shale formation. The resulting relatively pure methane gas can be stored for subsequent beneficial use at the subsurface, in the same way biogas generated from surface digesters is currently used at many modern sanitation plants.
The Terminal Island Renewable Energy (T.I.R.E.) demonstration project includes extensive field monitoring and sampling from sensors installed in both the injection and offset monitoring wells. This monitoring enables GeoEnvironment Technologies to instantly measure pressure and temperature variations at the point of injection and offset monitoring location in order to quantify slurry placement, biodegradation rates, carbon dioxide and methane separation, carbon dioxide sequestration and saturation in the formation brine, and free gas migration and production. This technology provides the following environmental and economic benefits over current practices:
- Enhanced treatment and sterilization of biosolids
- Greater protection for surface and shallow groundwaters
- Provides a local solution, reducing long distance truck traffic
- Reduced greenhouse gas emissions to the atmosphere
- Recycles waste into high quality clean energy for beneficial use