Input MSW can also be formulated into specialized feedstock referred to as Refuse Derived Fuel
(RDF), or Solid Recovered Fuel (SRF) as it is commonly referred to in Europe. RDF/SRF comes in two
primary forms: densified, hardened waste pellets or shredded waste fluff. This specialized incinerator
feedstock are often generated through propriety waste transformation processes, with the RDF/SRF
input material ranging from industrial waste materials, to rejected single stream recyclables, to
standard MSW. Exhibit 2 visually contrasts typical mass burn input feedstock and RDF feedstock.
A key distinction often integrated into the system design of a WtE plant using RDF/SRF as feedstock,
versus that for a mass burn WtE plant, is the addition of a MRF processing line at the front end of the
former. This approach may add significant facility complexity and capital/operational costs to the
overall system, but in the event of closure of the WtE plant, the process line components can
theoretically still be used to extract recyclables from MSW and/or as a RDF production line. The RDF
output also may have application as a salable fuel product in addition to being a WtE feedstock; such
material is used to fire cement kilns or industrial boilers and may generate carbon offset credits.