Waste-to-Energy (WtE), sometimes referred to as “Energy-from-Waste” (EfW), “incineration with
energy recovery”, or “mass burn” (if waste is not pre-processed) is the best-known and most widely
adopted MSW conversion method. There are currently four WtE facilities operating in Virginia as
listed below with their estimated throughputs in tons per day and tons per year. Collectively, the
facilities process an estimated 2.1 million tons of material per year.
No WtE facilities are currently operational in Kentucky, North Carolina, South Carolina, or Tennessee,
although there are approximately 80 to 100 facilities located nationwide. Some WtE facilities have
historically accepted material that has been pre-processed into pelletized or “fluffed” refused
derived fuel (RDF), as it is sometimes referred to in Europe, solid recovered fuel (SRF), for
consistency of feedstock and general combustion process managability.
WtE generally occurs at combustion temperatures (800 to 2200°F) in the presence of oxygen. They
have been proven to handle almost all MSW; very little pre-process is required. Generally, only bulky
items that can impede the WtE processing line such as large furniture, metal objects, and C&D
material must be removed, although chlorinated plastics are also commonly removed for purposes
of air pollution control system efficiency. However, input MSW is mixed for homogeneity, often with
excavation equipment or overhead cranes as shown in Exhibit 5.
Input MSW is fed into the combustion chamber where it is incinerated, heating a boiler and
generating steam to be used in a turbine generator for electricity production. Fly ash and pollutants
are collected in a flue gas cleanup stage. Heavier ash, inerts, and metals are collected and recycled
if appropriate. Thus, as with other thermal conversion processes, a portion (roughly 10% by mass) of
material inputs to WtE system must ultimately be landfilled. Exhibit 6 presents a potential WtE
process flow diagram.
Outputs of WtE include electrical power, a relatively stable bottom ash, fly ash (must be treated with
air pollution control technologies), and extracted or otherwise recovered materials such as bulky
items and recyclable metals.