Many communities are adopting greater diversion goals and must find new ways to reduce municipal solid waste. Technologies discussed at Tuesday’s session included Waste-to-Energy, Gasification, Plasma Arc, and anaerobic digestion of MSW.
Dan Costello with DHR Engineering, Inc. presented at the Waste Conversion Technologies session. To improve their waste diversion goals, DHR completed five international tours in three years to get a feel of the global community on waste diversion technologies.
Tour sites were chosen in Asia and Europe, including Japan, Germany and Belgium.
Waste-to-Energy sites are mainly used in Germany and Belgium. With more than 300 plants in Europe, this technology costs about $150-$200 US per ton.
Gasification processes are mainly present in Japan, but not in Europe, Dan said.
This technology seems to work best with more uniform and select waste feedstock. This technology costs about $300 per ton.
The Plasma Arc technology has operational issues due to fuel feed stock that is still being worked out, Dan said. No extension operation studies at a full load rate and cost per ton information were not available on the plasma arc technology.
The last technology he discussed included anaerobic digestion of MSW. Dan stated odor is a problem with this technology and no emissions data is available, though he expected emissions to be low compared to EPA MACT standards.
Patrick Matthews, with Salinas Valley Solid Waste Authority in California discussed their research on the autoclave system technology.
The authority is made up of five cities and eastern unincorporated area of Monterey County and generates approximately 260,000 tons of waste per year. Fortunately, their authority diverts 50 percent of their waste, but has set of goal of 75 percent by 2015 and 50 years of sustainable processing/disposal capacity.
With strong opposition to landfills, Patrick wanted to research other technologies to divert waste with less environmental impacts. The authority is conducting a 2-year testing program on the autoclave system.
The autoclave is basically a large pressurized steam cooker and looks like a big cement mixer, Patrick said. The authority is in second year of testing. When speaking about the marketability of products from steaming MSW in the autoclave, high amounts of cellulose remains. Cellulose is a feedstock for ethanol production. The autoclave can process up to 2 tons of municipal solid waste per day up to three times a day and reduces waste volume by 60 percent.
We have to consider new technologies because there will probably not be very many landfills built in the next 10 years, so we have to look at new ways to handle waste stream, Patrick added.
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