Did you know?

On average, it takes about one hour to process a ton of municipal solid waste at a Waste To Energy facility and deliver the resulting electricity to the power grid. In contrast, it is estimated that waste decomposition at a modern landfill takes 100 to 150 years.



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 Waste-To-Energy: How It Works

 

First, the trucks delivering waste are weighed at the scale house and monitored for safety. Once cleared, they enter an enclosed tipping area where they unload waste into a concrete storage pit. An overhead crane mixes the delivered waste (bulky objects that cannot be processed are removed and land-filled). The crane lifts the waste to the furnace hoppers located above the back wall of the pit. Air from the pit and tipping area is used for burning the waste. This prevents the escape of dust and odor from the building. Once in the furnace, the waste travels on moving metal grates. A minimum temperature of 1800 degrees F is used, assuring complete combustion and leaving little chance of releasing unburned pollutants.

Hot gases are carried up from the grate area through several boiler tube sections where heat is absorbed to produce steam. The gases pass from the boiler through a scrubber, where a water mist containing lime is mixed with the gases. The gases are cooled and a chemical reaction of the lime with the gases neutralizes any acids and produces particles that can be collected.

Next in the process line is a baghouse that works like a large vacuum cleaner, collecting particles produced in the boiler and scrubber. The cooled and cleaned gases are vented through a stack flue topping out at 200 feet above the ground.

The entire process is guided and monitored by operators from a central control room. All processing activities take place indoors to control dust odors, and to prevent rain water from coming in contact with either waste or ash. Metals in the ash are removed and recycled while the remaining ash is land-filled.

Steam from the boilers power a turbine generator, producing electricity to run plant equipment. The remaining electricity, about 95 percent of the total, is sold to Seminole Electric to be used in our homes and businesses.