Patent ID: 7138046

Claim:
A process for producing hydrogen from anaerobically digested organic materials comprising: (i) applying an intermittent electric potential across said materials to produce hydrogen and carbon dioxide-wherein said electric potential comprises a voltage applied by a voltage source according to a duty cycle that is adjusted by a controller, (ii) detecting methane production by gas detection means in communication with said controller; (iii) applying a voltage for a first time period until methane production is depressed; (iv) discontinuing application of voltage for a second time period; (v) detecting resumption of methane production by said gas detection means; (vi) applying a voltage for a third time period longer than said first time period; (vii) discontinuing application of voltage across electrodes for a fourth time period shorter than the second time period in step (iv); (viii) repeating steps (iii)–(vii) iteratively until methane production is minimized and hydrogen production is maximized.