Harvesting Biogenic Waste Streams for Energy

In 2010, the United States generated about 250 million tons of municipal solid waste. Approximately 34 percent of that was recycled or composted. Most of the rest was dumped in landfills. Can the nation do better?

The EPA recently released its annual report Municipal Solid Waste Generation, Recycling, and Disposal in the United States: Facts and Figures for 2010 . The data indicate that large amounts of biogenic materials (e.g., food waste, yard trimmings, paper, and wood) are still sent to landfills.

We at EESI note that much of the landfilled material rots underground over time, emitting greenhouse gases such as carbon dioxide (CO2) and methane. Most operating landfills are collecting the methane gas and either flaring it, without energy recovery, or burning it to produce electricity and/or useful heat. However, landfill methane collection systems do not catch all of the emissions. Reducing the amount of biogenic matter entering landfills is a better way to reduce and prevent methane emissions from municipal waste streams. While reducing, reusing, and recycling remain the leading strategies for reducing the volume of material going to landfills, capturing more energy value from the biogenic materials remaining in the urban waste stream can help, too. Anaerobic digester technology shows great promise, as reported in the following articles from Science Digest.

Making Chemicals from Biogas Instead of Burning It
Industrial By-Products Upgraded Into Fuel
Biogas Climate Benefit Greater than Previously Thought
Electricity from Straw and Other Waste Materials

To learn more about biogas production and use from waste streams, see the proceedings from a previous EESI briefing Renewable Biogas: Too Valuable to Waste .