To accelerate the start-up process and enhance the efficiency of a hydrogen production system, piggery anaerobic digested residues (PADRs) were subjected to several different treatment methods to enrich the hydrogen-producing bacteria. Eight treatment methods were performed on the PADRs, including acid, alkali, heat, drying, ultrasound, aeration, sodium 2-bromoethanesulfonate (BES), and chloroform. The best method was found to be drying at 60 degrees C for 48 h, which maximised the total biogas production and the hydrogen fraction without causing any methane production. The volatile fatty acids (VFAs) found after the drying treatment were acetate and butyrate, which together accounted for 91.9% of all VFAs, indicating that butyric acid fermentation was established. Due to the drying treatment, the metabolites produced from the biodegradable DOM were utilised more rapidly, more completely, and with the least amount of hard-degradation organic matter content obtained, according to EEM fluorescence spectra. This drying treatment offers a promising method to(1) improve bio-hydrogen production. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.