A controllable, continuous-feed system and process for the reduction or depolymerization of organic materials using microwave energy in a reducing, substantially oxygen-reduced atmosphere. The microwave energy is generated by a plurality of magnetrons in a microwave tunnel. Gaseous products may be extracted from the microwave tunnel for recycling and/or analysis. A collector such as a liquid trap may be used to separately collect floating and sinking constituents of the solid products while preventing the escape of the reducing atmosphere from the system.