Apparatus for the treatment of particulate biodegradable organic waste

1. An apparatus for treating particulate biodegradable organic waste comprising:

a thermal hydrolysis reactor receiving the particulate biodegradable organic waste for performing thermal hydrolysis at a temperature above about 130° C. and a pressure at or above the saturated water vapor pressure to produce a slurry including solubilized organic material and residual solids;

pH adjustment means for adjusting the pH of the particulate biodegradable organic waste as necessary to provide an acidic pH of greater than about 3.15 before thermal hydrolysis of the particulate biodegradable organic waste;

separating means receiving the solubilized organic material and residual solids for separating solubilized organic material from residual solids;

an anaerobic reactor configured to receive the solubilized organic material;

means for circulating the solubilized organic material from the separating means to the first separating means; and

the anaerobic reactor being configured to receive liquid including the solubilized organic material from the separating means and not solubilized organic material directly from the second separating means.

2. A method of treating particulate biodegradable organic waste comprising:

a) adjusting the pH of the biodegradable organic waste as necessary to provide acidic pH of greater than 3.15;

b) subjecting the particulate biodegradable organic waste with an acidic pH to thermal hydrolysis at a temperature above about 130° C. and a pressure at about or above the saturated water vapor pressure to produce a slurry including solubilized organic material and residual solids;

c) separating the solubilized organic material from the residual solids; and

d) subjecting the solubilized organic material to anaerobic digestion to produce a methane rich gas.

3. The method of claim 1 further comprising prior to step a), separating liquid from the particulate biodegradable organic waste.

4. The method of claim 1 further comprising:

a1) before step b), mixing the particulate biodegradable organic waste with the separated solubilized organic material of step c) to heat the particulate biodegradable organic waste;

a2) removing liquid, including the solubilized organic material, from the heated particulate biodegradable organic waste; and

a3) subjecting the removed liquid of step a) to the anaerobic digestion of step d).