Comprehensive experiments were designed to study the relative function of two bioreactor configurations viz., biofilm and suspended growth for dark-fermentative hydrogen (H-2) production along with wastewater treatment at two varying feed pH conditions (6 and 7). Both the reactors were operated in sequencing batch mode using anaerobic inoculum after pretreatment (combined treatment: acid-shock, heat-shock and chemical-shock). Biofilm system showed efficient H-2 production over the corresponding suspended growth operation at feeding pH 6. VFA profiles visualized high acetate fraction supporting feasible microenvironment for higher H-2 production. Voltammogram profiles visualized significant variation in the bio-electrochemical behavior with the function of operating pH and reactor configuration. It can be inferred from this study that biofilm systems are efficient for H-2 production particularly at acidiophilic microenvironment. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.