Recent Advance in Anaerobic Co-digestion Technology: A Review

Due to their polluting characteristics, fossil fuels presently tend to be replaced by renewable energy resources. Anaerobic digestion is a recent technology for producing biofuels. As a biochemical method to produce biogas, it is more environmentally friendly than other processes and is almost non-polluting. The anaerobic co-digestion is an upgrade of the mono-digestion since some limitations of the single-substrate degradation were solved by digesting two or more substrates. The present review gives an overview of the progress made in the anaerobic co-digestion technology. Appearing as a complex technology, lots of factors can affect its operation. Those factors include the choice and the composition of the substrates, the ratio between the substrates and the inoculum, the pretreatment, the environmental conditions, the operational parameters, and the post-treatment at the end of the process. Analytical and empirical tools for the assessment of the whole system in terms of biodegradability and synergy of the substrates, the efficiency of the process, and the identification of the operation inhibitors are also presented in this paper.