We most commonly think of the term "organic" in relation to naturally grown foods, so you may think the UTOC is able to consume only plant matter. Chemically speaking, the term "organic" refers to anything that includes carbon-bonded atoms, including plastics, rubber, various chemicals and gases, and biological material. All organics, by the chemical definition, can be processed by UTOC.
UTOC ash is the metal and mineral fractions of UTOC feedstocks.