Niches for bioelectrochemical systems on the recovery of water, carbon and nitrogen in wastewater treatment plants

Highlights: • MET integration within WWTPs shows potential to become a resource refinery. • CO₂ emissions at WWTP can be reduced using METs while valuable compounds are produced. • Water recovery in WWTPs is enhanced by using MET for NH₄⁺ and NO₃⁻ removal. • MET can be used for the recovery of NH₄⁺ from ammonium-rich water streams. • Integration rather than substitution is essential to attain the best configuration. -- Abstract: Climate change and future depletion of resources are two of the most important environmental challenges that humankind have ever faced. This mini-review aims to give a second chance to contaminated water and recalcitrant carbon dioxide (CO₂) streams by putting forward a resilience and sustainable technology based on electron-driven microbial reactions. A critical assessment of the current application of microbial electrochemical technologies (METs) in the field of electro bioremediation of contaminated water and bio-electro CO₂ recycling in wastewater treatment plants (WWTPs) is performed. Data from lab-scale and pilot-plant studies is shown to prove that MET is a highly promising and cost-effective technology for the sustainable remediation of contaminated sites while producing biofuels and/or commodity chemicals from recalcitrant CO₂ streams emitted in WWTPs.