Aqualia publishes in the Journal of Membrane Science
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Summary: One of the challenges of the implementation of Microbial Desalination Cell (MDCs) at larger scale lies in the supply of biodegradable organic matter from real wastewater as fuel for the bacteria growth in the anodic chamber. Anaerobic digestion can be used as pre-treatment step to enhance the availability of volatile fatty acids or VFAs (specially acetic acid) in real wastewater streams. However, the enrichment in VFAs strongly depends on the wastewater source. In the case of municipal wastewater, the enrichment in VFAs by anaerobic digestion still remain insufficient for an optimal operation of the MDC.
Taking into account that MDCs can produce around 1.8 kWh bioelectricity from the treatment of 1 m3 of wastewater, the concentration of the pre-treated and enriched VFAs-wastewater stands as a technically and economically feasible option to overcome the shortage of biodegradable organic matter in raw municipal wastewater. In this sense, this paper demonstrates that Forward Osmosis (FO) can be used as concentration step for volatile fatty acids to optimize downstream MDC. The required VFAs concentration for fueling the MDC was achieved at water concentration factors above 10 with no extra energy consumption associated.