A novel Ni/carbon catalyst recently developed by the authors was used to gasify organic compounds dissolved in the wastewater with TOC concentration from 0.2 to 2%. The process removes the organic compounds by gasifying them into high calorific gases like methane and hydrogen. The investigations were focused on the efficiency of the Ni/carbon catalyst in terms of carbon conversion, conversion of big organic molecules, and catalyst deactivation due to sintering. The preliminary results showed that up to 99% carbon conversion can be achieved at 360 degrees C, and 20 MPa. A conversion mechanism was suggested which consists of: first, decomposition of big molecules to small molecules on the metal surface, steam gasification of small molecules to produce CO and H-2 followed by CO methanation and CO shift reaction to produce CH4 and CO2. The catalyst was found to be highly active and stable and no sintering was observed even after 100 h of reaction time. (c) 2005 Elsevier Ltd. All rights reserved.