Comparison of the anaerobic digestion at the mesophilic and thermophilic temperature regime of organic wastes from the agribusiness Daniela Almeida Streitwieser Universidad San Francisco de Quito USFQ, Department of Chemical Engineering, Institute for Development of Alternative Energies and Materials IDEMA, Diego de Robles s/n y Av. Interoceánica, Quito D.M. 170157, Ecuador highlights  The rate of anaerobic digestion varies as function of organic load and temperature.  A global power law model for mesophilic and thermophilic anaerobic digestion is presented.  Activation energy and degradation rate are higher at thermophilic regime. graphical abstract article info Article history: Received 27 March 2017 Received in revised form 31 May 2017 Accepted 3 June 2017 Keywords: Anaerobic digestion Co-digestion Power law kinetic model Mesophilic–thermophilic transition abstract An overall kinetic power law model has been successfully applied to study the anaerobic digestion of agricultural wastes. In this comparative kinetic study feed composition, organic load rate, residence time and process temperature have been systematically varied in an automated semi-continuous fermentation system to obtain the dependency of the rate of degradation as biogas production on the organic load rate and temperature. The results show that the overall reaction order depend only on the Chemical Oxygen Demand (COD) at values between 3.6 and 3.7. The Arrhenius approach shows a shift in the rate determining step between the mesophilic and thermophilic temperature regimes. The activation energy at the temperature insen- sitive mesophilic regime is very small at 8.9 (kJ/mole), while the activation energy at the temperature sensitive thermophilic regime lies around 117 (kJ/mole). Ó 2017 Elsevier Ltd. All rights reserved. 1. Introduction The search for new energy sources has encouraged investors, researchers and costumers to look for new technologies to utilize the energy contained in water sources (hydro), sunlight (solar), or wind (Manzano-Agugliaro et al., 2013; Romo-Fernández et al., 2012). Also the residual biomass can be considered a renewable energy source, which is the organic material produced by photo- synthesis. The advantage of biomass, compared to the other men- tioned renewable energy sources, is that the energy contained in it can be stored, transported or transformed into gaseous, liquid or solid fuels (Naik et al., 2010; Saxena et al., 2009). The biomass energy can be used in thermal combustion processes or biochem- ical conversions. It can be distinguished between first or second http://dx.doi.org/10.1016/j.biortech.2017.06.006 0960-8524/Ó 2017 Elsevier Ltd. All rights reserved. E-mail address: dalmeida@usfq.edu.ec Bioresource Technology 241 (2017) 985–992 Contents lists available at ScienceDirect Bioresource Technology journal homepage: www.elsevier.com/locate/biortech