Spatial multicriteria GIS-based analysis to anaerobic biogas plant location for dairy waste and wastewater treatment and energy recovery (Barcelos, NW Portugal)

Intensification, concentration and specialization of dairy cow farms originate many activity by-products, such as wastewater and slurry which implies treatment costs, reduce environmental quality and promote social conflicts between the urban and rural population. These (by)products present a high potential for energy recovery from biogas produced in anaerobic digestion processes, thus contributing to sustainable development. This study is focused on the development of a GIS-based spatial support decision system that supports Multicriteria Analysis and Weighted Hierarchical Analysis (AHP) models aiming to identify site locations with appropriate conditions for the implementation of biogas production units, using waste and wastewater produced by the dairy cow farms in Barcelos municipality (NW Portugal). This spatially explicit model considers environmental, social and economic factors, as well as, legal location constraints tested with a consistent sensitivity analysis of the modelling processes and results. The results indicate sites with appropriate conditions for the location of biogas production units, considering the minimal distance to the dairy cow farms, electric and road networks, in higher areas with forest land cover and maximizing the distance from the urban spaces, as well as, from the river/ground water surfaces and agricultural/ecological reserves. In the next studies it´s relevant to explore biogas units dimensioning concerns, explore other complementary biomass sources in anaerobic (co)digestion solutions and expand collected spatial data to spatial decision support system during future biogas units operation phase.