Definitions:

Pyrolysis is the thermal processing of waste using indirect heat in the absence of oxygen

Gasification is the thermal processing of waste using heat, pressure, and steam to convert materials directly into a gas

Acid Hydrolysis is the chemical decomposition of waste using acid and water to split chemical bonds

Anaerobic digestion is the bacterial breakdown of organic materials in the absence of oxygen

Aerobic digestion is, essentially, composting of organic matter