Subsurface Geothermal Treatment

About 10 million tons of municipal sewage sludge (biosolids) are generated each year in the United States alone. Most biosolids are currently applied to land surface, where they biodegrade over time and release greenhouse gasses into the atmosphere. But the ratio of rural land to urban development is decreasing, and the volume and costs associated with biosolids disposal and recycling are steadily increasing worldwide.

Terralog Technologies has developed and patented an innovative technology to manage municipal biosolids and recycle this waste into clean energy. With appropriate geological formation selection, well design, and monitoring, biosolids slurry can be injected into soft, porous, sand formations at depths far below the surface (on the order of 5000ft or more).

The high temperature in the subsurface will treat and sterilize the biosolids instantly (within 24 hours). The biosolids material placed deep underground will undergo a natural process of continuing anaerobic biodegradation, much as naturally deposited organic layers undergo diagenesis over geologic time after deposition and burial. This geothermal biodegradation process at depth will generate methane and CO2 , as occurs in landfills. The CO2 is preferentially absorbed by formation waters (due to its higher solubility in water). High pressure, high purity methane can be stored or subsequently produced for beneficial use. 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