Effluent wastewater treament from biogas plants

Abstract

Biomethane production from the anaerobic digestion of animal wastes has regained popularity in Brazil and therefore is receiving especial attention lately. Biomethane is an alternative source of renewable energy that can contribute to local agribusiness economy whereas decreasing our dependency on petroleum. Therefore, large scale biogas plants have been considered to increase methane productivity to volumes that can make it commercially competitive. Despite the fact that biogas plants technologies are well established, little effort has been placed on how to treat the final wastewater adequately in order to maintain the sustainability of the process without jeopardizing its economic feasibility. The aim of this case-study was to determine the economic impacts of five most conventional wastewater treatment approaches available at local market on a specific pilot-scale biogas plant designed to operate in Southern Brazil. The benefits and technical limitations of each wastewater treatment approach were taken into consideration during analyses. The economic analyses were estimated based on net present value (NPV). Overall, the information gathered in this case-study can serve as guidance to decision makers during the development of newer biogas plants. Moreover, the results can assist public policies towards the development of sustainable agribusiness that is capable of producing biomethane as promising and profitable source of renewable energy.