Microbial fuel cells in the house: A study on real household wastewater samples for treatment and power

Abstract

In line with the global movement towards sustainable buildings and dwellings, this work investigated the potential for integrating microbial fuel cell technology into future architecture. Various types of domestic greywater and wastewater from five different sources (bathroom, kitchen sink, dishwasher, laundry washing machine and urinal) were tested as feedstock in otherwise identical MFCs. In terms of power output, urine outperformed other feedstock types by producing a maximum power of 3.91 ± 0.27 mW (97.8 ± 6.8 W m−3). The urine-fed MFCs showed a COD removal rate of 38.9 ± 1.1% and coulombic efficiency of 15.1 ± 3.4%. When urine was diluted with either bathwater or tap water, which represents a realistic scenario where flushing toilets are installed, results showed that MFC power output decreased with increasing dilutions. Interestingly, when commercial bleach was added in full concentration, although the level of instantaneous power dropped, performance recovered to the previous levels within 48 h after this was replaced with fresh urine. This suggests that the MFC systems are fairly robust and can be resistant to short-term domestic chemical exposure. These novel findings provide a stepping-stone to more sustainable future buildings and cities with fully integreated MFC technology.