The catalytic hydrogen production from hog manure using supercritical water gasification and partial oxidation was investigated in a batch reactor at a temperature of 500 degrees C, and pressure of 28 MPa using several metallic catalysts. Hog manure was characterized by a total and soluble chemical oxygen demand (TCOD, SCOD) of 57,000 and 28,000 mg/L, total and volatile suspended solids (TSS, VSS) of 25,000, 19,000, and ammonia of 2400 mg/L, respectively. The order of H(2) production was the following: Pd/AC > Ru/Al(2)O(3) > RU/AC > AC > NaOH, and the order of COD reduction efficiency was as follows: NaOH > Ru/AC > AC > Ru/Al(2)O(3) > Pd/AC. The behavior of the volatile fatty acids (VFAs), ethanol, methanol, ammonia, H(2)5, and sulfate was investigated experimentally and discussed. A 35% reduction in the H(2) and CH(4) yields was observed in the sequential gasification partial oxidation (oxidant at an 80% of theoretical requirement) experiments compared to the gasification experiments (catalyst only). Moreover, this reduction in gas yields was coincided with a 45% reduction in the liquid effluent chemical oxygen demand (COD), 60% reduction of the ammonia concentration in the liquid effluent, and 20% reduction in the H(2)S concentration in the effluent gas. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.