System for More Efficient Anaerobic Digestion of Waste

Technology #11483

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David P. Chynoweth
Patrick J. Haley
Arthur A. Teixeira
John M. Owens
Managed By
John Byatt
Assistant Director 352-392-8929
Patent Protection
US Patent 7,153,428


The University of Florida is actively seeking a company interested in commercializing a system for efficient anaerobic conversion of waste. Traditionally, landfills have been a common method of waste disposal. Unfortunately, landfills produce large amounts of hazardous gasses and tend to pollute underground water supplies, surface streams, and wells. Furthermore, due to the slow stabilization of waste, landfills may not be used for other purposes for long periods of time and are thus a large waste of land, particularly in metropolitan areas. Other approaches to waste disposal use anaerobic digestion of organic waste. Current methods of anaerobic digestion involve pumping liquid between bioreactors. However, this process frequently traps gasses in the waste and causes a blocking of liquid flow in the system, which can cause the system to malfunction, and hinder the anaerobic digestion of waste. To solve these problems, University of Florida engineers have invented a system for efficient anaerobic conversion of waste that prevents gas from becoming entrapped and that keeps liquid flowing through bioreactors without impediment.


Anaerobic digestion of waste


  • Used for disposal of variety of wastes ranging from trash to human waste to water treatment sludge providing broad commercial application
  • Prevents the blockage of liquid that stalls anaerobic digestion of waste in bioreactors increasing operational efficiency
  • Generates recycled compost and gas that can be used for energy in fuel cells

  • Reduces bioreactor sizes and processes waste at lower temperatures than current systems reducing overall operational costs


This invention is a high-solids flooded leachbed anaerobic composting system that reduces bioreactor sizes and processes waste at lower temperatures than current systems. By operating in a flooded mode with periodic flow reversal, the system invented here prevents displacement of fluid and the clogging that results from gas entrapped in waste. Moreover, the flooded mode of operation increases surface area contact between liqud leachate and solid waste particles to dramatically enhance reaction rates thereby reducing process time and size of reactors. This system can be used for disposal of various forms of waste, including: solid waste, landfill waste streams, waste produced in food industries, water treatment sludge, recycling waste, agricultural waste, yard waste, paper trash, cellulosic packaging materials, human and animal waste, and other organic wastes. This system converts organic matter into useful microbial fermentation products and compost. After anaerobic digestion is complete, the compost bed in this system can be recycled for further use in applications such as biofiltration and as a plant growth medium. This technology can also be used for other feedstocks, including industrial eastes, agricultural residues, and energy crops. Moreover, in this system, gas that is created during anaerobic digestion can be used for energy, such as in a fuel cell.