From Fossil Fuels to Renewable Biogas Production from Biomass Based Feedstock – A Review of Anaerobic Digester Systems

Abstract

Three-quarters of the global energy consumption is expected to come from fossil fuels by 2040 despite many drawbacks to the world’s reliance on fossil fuels. The primary drawback of fossil fuels is in procuring, transporting, refining, and combusting them which generates pollution biproducts, global warming, which in turn generate a plethora of associated problems. Biomass as a renewable resource and its conversion into renewable fuel products can offset use and drawback of fossil fuels. Anaerobic digestion is known since the 10thcentury BC has become today a versatile tool to produce renewable energy in form of biogas from many biomass-based feedstock sources. These sources can be agriculturally based such as livestock waste, energy crops, plant (lignocellulosic) based, forest residues, or industrial and municipal waste such food waste, wastewater treatment sludge, distiller grains and food product residues. Feed stocks can be used in anaerobic fermentation processes as single or co-digest feedstock. Each feedstock represents a challenge on its own for anaerobic digestion processes in order achieve good operational stability and good biogas production. Selecting a suitable anaerobic fermentation process from today’s available technical sound processes described in this review is essential for future fossil fuel independence.