Relationship between pH, Oxidation Reduction Potential (ORP) and Biogas Production in Mesophilic Screw Anaerobic Digester

Anaerobic digestion is a biological process that can be used for food waste and leachate treatment. A semi-continuous anaerobic digestion experiment was carried out treating a synthetic feedstock made of 50% synthetic food waste and 50% leachate. The total solids concentration inside the reaction was maintain constant and different TS were investigated varying from 5 to 7% TS. The aim of this study was to investigate the effect pH and Oxidation Reduction Potential (ORP) on the biogas production at the different organic loading rate tested. These operational parameters were used to predict and control a mesophilic screw digester. The results of this study indicated that the optimum of ORP and pH during the acidogenesis phase were -28 +/- 32.71 mV and 5.76 +/- 0.24, respectively. The optimum of ORP and pH during the methanogenesis phase were -335.63 +/- 28.97 mV and 7.49 +/- 0.24, respectively. The highest biogas and CH4 content were obtained for the OLR equal to 5%TS condition. The value of biogas and CH4 content were0.29 L biogas/g COD utilized and 68% of methane content, respectively. (C) 2017 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the scientific committee of the 2017 International Conference on Alternative Energy in Developing Countries and Emerging Economies.