Turning Waste into Fuel

If all of the cattle, swine and poultry waste across the United States could be collected and converted to electricity, the resulting energy could produce 80 percent of the nation’s current electrical power needs, while also generating marketable high-end plants and extracts. And the system works, at least on a smaller scale, according to research by civil engineering professor, Clifford Fedler. Fedler believes the country is largely ignoring an unlimited source of renewable energy – animal waste and other biomass – which is nothing more than any dry organic material like yard clippings, paper, residual material from cotton fields or other agricultural leftovers.

Biomass as Renewable Energy

Fedler funded the research with a grant from the State Energy Conservation Office. He recently received a second grant from the organization to perform an economic analysis of his biomass recycling system. Other departments across campus are assisting in the analysis; agricultural economics to assess marketing costs, and industrial engineering to assess the engineering economics of the system. “The U.S. Department of Agriculture put out a report two years ago that says in the future, there will be 1.2 billion tons of biomass available for energy production,” Fedler said. “What I have found is that if animal waste is recycled into biomass (dry material) rather than using fresh water sources, we have the potential to produce more than 4 billion tons annually, which is sufficient to produce nearly 80 percent of the nation’s current electrical energy usage.” In addition, the heat produced in the conversion process could be used in ancillary businesses such as greenhouse vegetable systems for year-round production, Fedler said. Biomass energy has several advantages over wind and solar energy – mainly that it can be designed to be available 24/7, whereas wind and solar energy are site specific and rely heavily on climatic conditions and time availability.

Intregrated Recycling Systems

By integrating various technologies together, such as water recycling with fish production, not only can additional biomass be generated, but negatively impacted water can be remediated, resulting in a cleaner environment. Additionally, integrated systems have the potential to produce valuable byproducts that result in new jobs and sustainable economic growth, particularly in rural communities. Fedler’s integrated modular production system would operate differently in various parts of the country, depending on the resources available at a given locale. In an arid or semi-arid region like West Texas, a hypothetical integrated recycling system would operate as follows:

• Cattle waste from a feedlot is converted into energy using a gasifier or separated to produce hydrogen gas and carbon fiber, a high-strength structural material.
• Feedlot runoff water is treated in a series of ponds with aquatic plants such as cattails and water hyacinth. The plants are supplied to the gasifier and the water used to grow a high-protein plant such as duckweed, after which it would be clean enough to water the cattle or to produce fish for the aquarium market. The duckweed is harvested and used as fish or cattle feed.
• Water from the fish production system can produce other edible plants such as organic tomatoes or other organic food plants.
• Additional opportunity lies in plants grown specifically for their profitable extracts for the nutritional supplement market, many of which have a higher value than traditional plants, all byproducts are consumed onsite.

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