Using apple pomace (AP) as substrate, a series of batch experiments were conducted to investigate the effects of activated sludge pretreated by ultraviolet and ultrasonic on the anaerobic fermentative bio-H(2) production. The results show that a maximum cumulative H(2) production (CHP(m)) of 107.0 ml g(-1)-TS and an average H(2) production rate (AHPR) of 15.0 ml g(-1)-TS h(-1) were obtained by using the pretreated sludge that was irradiated by ultraviolet lamp (25 w) for 15 min as inoculant. Based on the optimal sludge pretreatment method, the experiments of bio-H(2) production under the optimal substrate pretreatment condition (soaked in the ammonia liquor of 6% for 24 h) were further carried out, and the CHPm of 138.8 ml g(-1)-TS was achieved, increased by 80.6% compared to the un-pretreated group (76.8 ml g(-1)-TS). The effects of the various organic acids on the fermentative H(2) production were also investigated under the above optimal sludge pretreatment condition. Crown Copyright (C) 2010 Published by Elsevier Ltd. All rights reserved.