Design of a biogas plant fed with Cladophora Sp. algae and wheat straw

The blooming of biogas plant installation undergoing wet anaerobic digestion processes is an evident trend at EU condition. The use of biological feedstocks from farm and agricultural origins together with the use of alternative feedstock like marine macroalage provide benefits in terms of waste management and avoided natural resource extraction. Nevertheless, the seasonal fluctuations of the type and amounts of feedstocks available for a specific biogas plant, together with their optimal co-digestion, can affect the overall efficiency and optimization of the biogas operations with potential drawback on the overall sustainability of the system. A proper design of the biogas plant is thus a key step to have profitable biogas-based systems. In this paper, based on the available literature around the topic of design and sizing of a biogas plant and on interviews with practitioners in the field, the design of all the system components of a biogas plant fed with Cladophora Sp. algae and wheat straw is reported. The kinetical analysis of the digestion and the biomethane potential of the biomass employed have been determined based on a set of experiments lead by the authors. The scope of the presented case study is to help to fill the gap identified in literature and take a step towards defining standards and benchmarks for the sector and to provide a step-by-step approach for biogas plant design.