A proof of concept study for wastewater reuse using bioelectrochemical processes combined with complementary post-treatment technologies

Role of bio-electrochemical technology for enzyme activity stimulation in high-consumption pharmaceuticals biodegradation

Active pharmaceutical ingredients (APIs) and their intermediate residues have recently been considered a serious concern. Among technologies, bio-electrochemical technologies (BETs) have stimulated the production of bio-electrical energy. This review aims to examine the benefit and mechanism of BETs on the degradation of high-consumption pharmaceutical compounds, including antibiotic, anti-inflammatory, and analgesic drugs, and the stimulation of enzymes induced in a bioreactor. Moreover, intermediates and the proposed pathways of pharmaceutical compound biodegradation in BETs are to be explained in this review. According to studies performed exclusively, the benefit of BETs is using bio-electroactive microbes to mineralize recalcitrant pharmaceutical contaminants by promoting enzyme activity and energy. Since BETs use the electron transfer chain between bio-anode/-cathode and pharmaceuticals, the enzyme activity is essential in the oxidation and reduction of phenolic rings of drugs and the ineffective detoxification of effluent from the treatment plant. This study is suggested a vital and influential role of BETs in mineralizing and enzyme induction in bioreactors. Eventually, a content of future developments or outlooks of BETs are propounded to improve the pharmaceutical industries' wastewater problems.

Microbial Electrolysis Cell as a Diverse Technology: Overview of Prospective Applications, Advancements, and Challenges

Microbial electrolysis cells (MECs) have been explored for various applications, including the removal of industrial pollutants, wastewater treatment chemical synthesis, and biosensing. On the other hand, MEC technology is still in its early stages and faces significant obstacles regarding practical large-scale implementations. MECs are used for energy generation and hydrogen peroxide, methane, hydrogen/biohydrogen production, and pollutant removal. This review aimed to investigate the aforementioned uses in order to better understand the different applications of MECs in the following scenarios: MECs for energy generation and recycling, such as hydrogen, methane, and hydrogen peroxide; contaminant removal, particularly complex organic and inorganic contaminants; and resource recovery. MEC technology was examined in terms of new concepts, configuration optimization, electron transfer pathways in biocathodes, and coupling with other technologies for value-added applications, such as MEC anaerobic digestion, combined MEC–MFC, and others. The goal of the review was to help researchers and engineers understand the most recent developments in MEC technologies and applications.

Microbial electrochemical systems for hydrogen peroxide synthesis: Critical review of process optimization, prospective environmental applications, and challenges

Hydrogen peroxide (H₂O₂) is an industrial chemical that has been widely adopted for various industrial applications, including water and wastewater treatment. Currently, the majority of H₂O₂ is being produced through the anthraquinone oxidation process, which is disadvantageous due to the requirement of toxic raw materials and high energy input. Recently, microbial electrochemical cells (MXCs), such as microbial fuel cells and microbial electrolysis cells, have demonstrated great potential for effective H₂O₂ production via cathodic oxygen-reduction reaction (ORR). Previous studies have specified key operational parameters for scaling-up of H₂O₂-producing MXCs, where improvements in production rate, conversion efficiency, product concentration and stability are attainable. Moreover, various systems have demonstrated their value proposition in the contaminant removal aspects through direct removal of various environmental pollutants, water disinfection, and many more. This review is intended to highlight promising ways of H₂O₂ production with MXCs and on-site environmental applications of bioelectrochemically-produced H₂O₂.

2019 Best Papers published in the Environmental Science journals of the Royal Society of Chemistry

The Editors-in-Chief of the Environmental Science journals introduce the Best Papers of 2019.