A method of treating mixed fruit peel waste was investigated using anaerobic contact filter based on bio-hydrogen generation. The effectiveness of anaerobic treatment was monitored by varying the influent volatile solid content (46, 66 and 84g/L) and hydraulic retention time (HRT) (3, 5, 7, 10, 13, 15 and 18 days). The results showed that for an influent volatile solid content of 46, 66 and 84g/L a HRT of 10, 13 and 18 days were required to achieve a volatile solid destruction efficiency of 60%. The hydrogen content in the biogas reached a stable value of 63 +/- 2%, irrespective of influent volatile solid concentration and HRT. While the average biogas generation for the mixed fruit peel waste was found to be 0.73 m(3) /kg VS destroyed at a HRT of above 5 days. (c) 2007 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.