Electro-Fenton systems for “on-site” sanitary wastewater treatment: Towards an off-grid technology for developing countries

Nowadays, 2.3 billion people in the world (almost a third of the planet´s population) live in communities that lack a sewer system and the financial resources for its installation. In this work, two electrochemical reactors based on the Fenton reaction were evaluated as a tertiary treatment for real sanitary wastewater which was obtained from a pre-treatment using biological processes. The evaluated systems were solar-powered, modular, off-grid operated and tested for open use. The processes consist on treating real sanitary wastewater with an anaerobic biodigester followed by a biological anoxic-aerobic stage and finally using the electrochemical reactors. The solid waste is stabilized using a solar heater and the outcoming aqueous effluent has an average organic matter concentration measured as chemical oxygen demand of 30.6 ± 10.1 mgO2 L−1, biological chemical demand of