Wet anaerobic bio gas plants are more suited to large scale livestock (manure) and industrial (organic waste) projects with their continuous / perpetual system operations. Though more complex in operations, these can take animal waste, agricultural solid waste and crop residues as well as green energy crops. However, these systems are not suited for high solid content substrates and resultantly need substrate management (size and liquid mix) for a suitable solid content for the Bio Gas Plant. These plants thus, have higher water and energy requirements than dry anaerobic plants.