A method for treating particulate biodegradable organic waste includes sizing
the
waste and adding a base prior to introducing the waste to a thermal hydrolysis
reactor and hydrolyzing the waste at a temperature of about 130 C. or greater
and a pressure greater than the saturated water vapor pressure to produce a slurry
including solubilized organic material and residual solids. The solubilized organic
material is separated from the residual solids using a liquid/solid separator and
the solubilized organics are subjected to anaerobic digestion to produce a methane
gas. The base is preferably potassium hydroxide (KOH) at a concentration of about
1%. The method may further include preheating the particulate biodegradable organic
waste with latent heat of the separated solubilized organic material prior to thermal hydrolysis.
