<p>A feed system includes a buffer assembly that receives material to be fed to a gasifier. The buffer assembly has structure that pre-processes the material for delivery to the gasifier. A rotary valve is positioned relative to the buffer assembly to receive the material from the buffer assembly. A digester receives the material from the first rotary valve, where the rotary valve conveys the material to the digester and includes a gas lock that prevents gas from escaping the digester. The digester is operable as one of a dryer and a gasifier depending on its operating parameters.</p>
