Increasing self-sufficiency of a wastewater treatment plant with integrated implementation of anaerobic co-digestion and photovoltaics

The transition for a circular economy is considered as a development pillar of European Union, due to the conservation and continued valuation of resources in the economy. This requires an integrated approach addressing energy consumption, use of raw materials, treatment and valorization of resources, new business models and synergies among industrial stakeholders. Managing and adding value to organic residues is a challenge and an opportunity for industries that produce these by-products. If anaerobic digestion is fundamental in this valuation, the quality and quantity of the obtained biogas, as well as the required energy intensity, dictate the participation of these stakeholders in the circular economy. A systemic approach is proposed in this work, fostering the vision of a circular economy in industries that generate organic residues, by considering the potential of renewable energy (photovoltaics) for self-consumption of locally generated electrical energy, and anaerobic co-digestion for improving the efficiency of biofuel production. A wastewater treatment plant is analysed, and the benefits of this integrated approach are highlighted.