Integrating local solar energy and water recovery: Operating experiences of a systemic approach

The key message is the importance of a systemic approach to handling water and energy together, both in design and in operation. The paper demonstrates how renewable energy, solar photovoltaic (PV) and solar thermal, in combination with a small nutrient removal plant, provides a reliable solution for small-scale decentralized water recovery operations. The system is automated and can operate outside the power grid and is designed to be a fully circular system in terms of both energy and water. The system has been installed on an island in the archipelago outside Stockholm, Sweden, to replace an old-fashioned septic tank. The effluent must satisfy rather strict effluent quality criteria for the Baltic Sea. The paper describes design considerations, instrumentation aspects, automation features, and operation experiences. HIGHLIGHTS The key message is the importance of a systemic approach to handling water and energy together, both in design and in operation.; The paper demonstrates how renewable energy, solar PV and solar thermal, in combination with a small nutrient removal plant provides a reliable solution for small-scale decentralized water recovery operations.;