Biological fuel cells produce bioelectricity with in-situ brackish water purification

Systematic and quantitative analysis of two decades of anodic wastewater treatment in bioelectrochemical reactors

Wastewater treatment is generally performed using energy-intensive processes, such as activated sludge. Improving energy efficiency has become one of the main challenges for next-generation wastewater treatment plants. Bioelectrochemical systems (BES) have been attracting attention because they take advantage of the chemical energy contained in wastewater while enabling the valorization of effluents: either with electrical energy (microbial fuel cells) or with useful chemicals (microbial electrolysis cells). Bioelectrochemical wastewater treatment has been under investigation since the early 2000s and is now the subject of an abundant literature, which is most frequently focused on anodic COD removal. Comparing results obtained in different studies is particularly difficult with BES, because many different parameters (effluent characteristics, inoculation, design, and operation) may interact and because using real effluents results in high variability. To address this issue, data were retrieved from 1,073 articles that were selected objectively and with transparency. This systematic review evaluates the potential of anodic wastewater treatment, based on 4,579 experimental observations. Overall, BES has already shown satisfactory treatment capacity, with a median chemical oxygen demand removal of 72%. However, the median coulombic efficiency was only 18%, increasing this parameter offers the greatest opportunity for BES improvement.

Anoxic-biocathode microbial desalination cell as a new approach for wastewater remediation and clean water production

Bioelectrochemical systems are emerging as a promising and friendly alternative to convert the energy stored in wastewater directly into electricity by microorganisms and utilize it in situ to drive desalination. To better understand such processes, we propose the development of an anoxic biocathode microbial desalination Cell for the conversion of carbon- and nitrogen-rich wastewaters into bioenergy and to perform salt removal. Our results demonstrate a power output of 0.425 W m^-3 with desalination, organic matter removal and nitrate conversion efficiencies of 43.69, 99.85 and 92.11% respectively. Microbiological analysis revealed Proteobacteria as the dominant phylum in the anode (88.45%) and biocathode (97.13%). While a relatively higher bacterial abundance was developed in the anode chamber, the biocathode showed a greater variety of microorganisms, with a predominance of Paracoccus (73.2%), which are related to the denitrification process. These findings are promising and provide new opportunities for the development and application of this technology in the field of wastewater treatment to produce cleaner water and conserve natural resources.

Prospects in bioelectrochemical technologies for wastewater treatment

Bioelectrochemical technologies are emerging as innovative solutions for waste treatment, offering flexible platforms for both oxidation and reduction reaction processes. A great variety of applications have been developed by utilizing the energy produced in bioelectrochemical systems, such as direct electric power generation, chemical production or water desalination. This manuscript provides a literature review on the prospects in bioelectrochemical technologies for wastewater treatment, including organic, nutrients and metals removal, production of chemical compounds and desalination. The challenges and perspectives for scale-up were discussed. A technological strategy to improve the process monitoring and control based on big data platforms is also presented. To translate the viability of wastewater treatment based on bioelectrochemical technologies into commercial application, it is necessary to exploit interdisciplinary areas by combining the water/wastewater sector, energy and data analytics technologies.