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The work is devoted to a comprehensive study of the plant bioelectrochemical systems (BES) properties, including both electrogenic characteristics and monitoring of gas composition changes in the near-electrode areas, as well as photosynthetic, biochemical and morphological parameters of the resulting plant products. Tomatoes and three different growing systems were selected as a test object – using panoponics technology, peat substrate and sod-podzolic sandy loam soil. The BES voltage using a nutrient solution was 35-180 mV, peat – 160-430 mV, soil – 160-590 mV, depending on the stage of plant development. The carbon dioxide content in the near-electrode areas of the BES was increased on average by more than 5 times. An increase in the amount of hydrogen content by 40% compared to air in peat-based BES was discovered. The presence of compounds with m / z = 56 and m / z = 64 in the gas component of the near-electrode areas has been identified. It was shown that tomatoes grown in BES with soil had better photosynthetic characteristics and higher yields. The identified increase in the amount of hydrogen in the BES in the context of plants cultivation using a peat substrate opens new possibilities for hydrogen biosynthesis. The prospects for the use of agricultural technological energy complexes are in the integrated obtaining of environmentally friendly energy, high-quality plant products and the microbiological production of biohydrogen. [ABSTRACT FROM AUTHOR]

Composting microbial fuel cells can generate electricity from recycled organic waste at accelerated degradation rates. However, the problem of high internal resistance ( R int ), which results in low power density, is a technical obstacle related to this process, and the preferential conversion of the organic fraction by bioelectrogenesis remains unclear. This study involved designing a novel three-chamber bioelectrochemically assisted anaerobic composting process (AnC BE,III ) to dispose of dewatered sludge (DS), which was operated at reduced internal resistance. The maximum power density of the AnC BE,III was higher (7.0–8.6 W/m 3 ) than that of the two-chambered AnC BE,II (4.7–5.7 W/m 3 ), with lower R int (63.8–88.5 Ω) than that of the AnC BE,II (78.8–98.5 Ω). At the end of composting, the AnC BE,III had higher total chemical oxygen demand (TCOD) removal (42.3 ± 0.5%) than the AnC BE,II (32.1 ± 0.5%). During electrogenesis, the dissolved organic carbon (DOC) [hydrophilic fraction and hydrophobic acid fraction of EBOM] (extracellular biological organic matter) was substantially removed, the hydrophobic neutral fraction of aromatic macromolecules was increasingly solubilized (by 13.2%), and the aromatic protein-like and humic acid-like substances were substantially removed. The results demonstrate that the increases in both the proton exchange area and cathode surface area in the AnC BE,III can enhance electricity generation and organic matter degradation. [ABSTRACT FROM AUTHOR]

• SSRMs boosted running properties of bioelectrogenesis and acidogenesis effectively. • SSRMs improved the protein and carbohydrate metabolisms-related genes' expression. • SSRMs elevated electron transfer efficiency by up-regulating cytochrome c oxidase. • SSRMs raised microbial diversity to realize superior bioelectrogenesis/acidogenesis. Anaerobic biological treatment was regarded as one of promising options for realizing concurrent WAS reduction, stabilization and bioenergy/bioresource recycle. But the relatively low treatment efficiency limited its spreading application toward larger scale considerably in China. Aimed at such barrier, this study offered a novel enhancing strategy for achieving high-efficiency of bioenergy/bioresource recycle from WAS anaerobic treatment via improving bioelectrogenesis/acidogenesis using sludge source-redox mediators (SSRMs). SSRMs not only facilitated bioeletrogenesis with an increasing efficiency of 36% for voltage output and 39% for bioelectricity bioconversion, but also enhanced acidogenesis of WAS with a mean elevating efficiency of 37.5% of volatile fatty acids (VFAs) production within 5 d Mechanistic investigations indicated that SSRMs had a potential influence on improving the protein and carbohydrate metabolisms-related genes' expression for enhancing bioelectrogenesis and acidogenesis. Moreover, SSRMs exerted roles of electrochemical "catalysts" or as terminal electron acceptors with affecting functional proteins of complexes of Ⅰ and Ⅳ in electron transfer chains for improving electron transfer efficiency. Meanwhile, the core members' abundance, microbial diversity and community distributive evenness were prompted concurrently for carrying out superior bioelectrogenesis and acidogenesis. A schematic illustration was established for demonstrating the mechanism of SSRMs for enhancing bioelectrogenesis and acidogenesis via changing microbial metabolism functions, enhancing electron transfer efficiency, and regulating functional genes' expression of functional proteins (up-regulating cytochrome c oxidase and down-regulating-NADH dehydrogenase). This study provided an effective enhancing strategy for facilitating WAS bioconversion to bioenergy/bioresource with well-process sustainability. [Display omitted] [ABSTRACT FROM AUTHOR]

A waste biorefinery is a means to valorize waste as a renewable feedstock to recover biobased materials and energy through sustainable biotechnology. This approach holistically integrates remediation and resource recovery. Here we discuss the various technologies employable to construct a waste biorefinery platform and its place in a biobased economy. [ABSTRACT FROM AUTHOR]

The present study evaluates the sequential integration of two advanced biological treatment methods viz., sequencing batch reactor (SBR) and bioelectrochemical treatment systems (BET) for the treatment of real-field petrochemical wastewater (PCW). Initially two SBR reactors were operated in aerobic (SBR Ae ) and anoxic (SBR Ax ) microenvironments with an organic loading rate (OLR) of 9.68 kg COD/m 3 -day. Relatively, SBR Ax showed higher substrate degradation (3.34 kg COD/m 3 -day) compared to SBR Ae (2.9 kg COD/m 3 -day). To further improve treatment efficiency, the effluents from SBR process were fed to BET reactors. BET Ax depicted higher SDR (1.92 kg COD/m 3 -day) with simultaneous power generation (17.12 mW/m 2 ) followed by BET Ae (1.80 kg COD/m 3 -day; 14.25 mW/m 2 ). Integrating both the processes documented significant improvement in COD removal efficiency due to the flexibility of combining multiple microenvironments sequentially. Results were supported with GC–MS and FTIR, which confirmed the increment in biodegradability of wastewater. [ABSTRACT FROM AUTHOR]

• Fruit waste extracts raised microbial diversity with more power generation via MFCs. • Cooperation of key members and interactions toward bioelectrogenesis were proposed. • An illustration of co-locating scenario for maximizing power recovery was evaluated. This first-attempt study illustrated the microbial cooperative interactions related to bioelectricity generation from the mixture of sludge fermentation liquid (SFL) and fruit waste extracts (FWEs) via microbial fuel cells (MFCs). The optimal output voltages of 0.65 V for SFL-MFCs, 0.51 V for FWEs-MFCs and 0.75 V for mixture-MFCs associated with bioelectricity conversion efficiencies of 1.061, 0.718 and 1.391 kWh/kg COD were reached, respectively. FWEs addition for substrates C/N ratio optimization contributed considerably to increase SFL-fed MFCs performance via triggering a higher microbial diversity, larger relatively abundance of functional genes and microbial synergistic interactions with genera enrichment of Clostridium , Alicycliphilus , Thermomonas , Geobacter , Paludibaculum , Pseudomonas , Taibaiella and Comamonas. Furthermore, a conceptual illustration of co-locating scenario of wastewater treatment plant(s), waste sludge in situ acidogenic fermentation, fruit waste collection/crushing station and MFC plant was proposed for the first time, which provided new thinking for future waste sludge treatment toward maximizing solid reduction and power recovery. [ABSTRACT FROM AUTHOR]

• A novel paraboloid graphite based MFC was built for PIW treatment and bioelectrogenesis. • MSW was used as a substrate for the development of biofilm and biocatalyst. • Maximum power and current densities achieved were as 2.01 W/m3 and 168 mA/m2. • Maximum COD and TDS removal for PIW were attained as 80.55 and 35.62%. • Membrane-less MFC showed feasibility for PIW treatment and bioelectrogenesis. The raising pharmaceutical industrial wastewater (PIW) is one of the major health problems nowadays, not only for aquatic life but also for human beings and the environment. Several conventional techniques including coagulation, filtration, biological membranes and advanced oxidation have been used for the treatment of PIW, however, all of these techniques are limited with their applications and results. The present study aimed to build a cost-effective, high biodegradable, eco-friendly and highly efficient PIW treatment technique to generate electricity and reduce the COD of wastewater simultaneously. A novel paraboloid shaped graphite-based microbial fuel cell (MFC) configuration has been designed by eliminating different types of casings and membranes for bio-electrogenesis and treatment of PIW. Municipal solid wastewater (MSW) was used as a substrate for developing the biofilm in paraboloid graphite-based MFC. The PIW treatment showed adequate bioelectricity generation including; current, power, voltage and open-circuit voltage (OCV) of about 2.76 mA, 0.76 mW, 276 mV and 330 mV at 100 Ω respectively after five operating cycles. The cyclic voltammetry showed the maximum generation of 2.01 W/m3 and 168 mA/m2 of power and current densities respectively followed by a considerable reduction in internal resistance from 197 to 99 Ω. The results reported a significant amount of reduction in COD (80.55%) and TDS (35.62%) for PIW by MFC respectively. The reduction in the percentage removal efficiency of COD (80.55%) suggested that the removal of organic compounds from PIW is parallel to bioelectrogenesis. Based on these major findings the novel membrane-less and paraboloid graphite-based MFC operation significantly drag concentration towards the feasibility of using pharmaceutical wastewaters for bio-electrogenesis. [ABSTRACT FROM AUTHOR]