Microbial electrochemical snorkel for optimization of wastewater treatment bioprocesses – BIOTUBA

In urban areas, the amount of electrical energy expenditure for water treatment and supply could reach up to 18%. Within wastewater resource recovery facilities (WRRF), oxygen supply to microorganisms for carbon and nitrogen biological removal remains the main source of energy consumption (up to 75% of the overall power expenditure of the WRRF). Also, the development of alternatives to conventional processes is essential to reduce the environmental impact of these treatment units. Bio-electrochemical systems represent a technology in the making for the treatment and valorization of waste, based on catalysis of electrochemical reactions by microbial biofilms on electrode surfaces. Among these technologies, the bioelectrochemical snorkel (BIOTUBA) is original due to its simpler operation that allows to consider short-term implementation in existing WWTP bioreactors. This technology consists of a bio-anode and a (bio-)cathode connected in short-circuit. It ensures a maximal efficiency of the oxidation of organic matter and substantial energy savings can be considered. In addition, this technology could meet other issues of the water treatment (process control, reduction of the sludge production or metallic micro-pollutant treatment).

Several scientific and technical challenges must be raised before considering the implementation of such technologies at industrial scale. The cost of electrodes, due to the expensive materials used for their design, is a constraint on scale-up. In addition, researches shall be conducted to allow fundamental understanding and to optimize the bioelectochemical snorkel specifying both microbial and electrochemical processes governing its performance.

The BIOTUBA project aims to raise scientific and technical barriers to the implantation of the bioelectrochemical snorkel at industrial scale through a transdisciplinary and multiscale approach. The scientific program of the project is divided in different tasks: (i) Studies at laboratory scale to understand and optimize the operation of BIOTUBA by focusing on the use of low-cost recycled materials and application to real matrices (WP1); (ii) Development and use of models for electrode design and implementation in industrial bioreactors (WP2); (iii) Evaluation of energetic and environmental impacts of BIOTUBA on wastewater bioprocesses using an life cycle analysis coupled to experiments at semi-industrial scale (WP3).

The development of the BIOTUBA will be based on the precise knowledge of the electrochemical and biological mechanisms to optimize its operation and to maintain its performance over time. Experiments at a semi-industrial scale will allow to characterize its behavior and induced impacts at a representative scale and to validate the technological choices. The economic development will be supported a partner of the project (6TMIC).

The project involves five partners: an Institute for applied research (Irstea-HBAN), an academic laboratory (LGC), a public industrial enterprise for urban wastewater management and treatment of the Parisian area (SIAAP) and a private company SME specialized in the development of innovative processes and technology transfer (6TMIC). Coordination will be provided by Irstea-HBAN.