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Increasing worldwide milk manufacturing and dairy processing resulted in producing more effluents, and thus effective management of wastewater is now the most important issue. This study used a new design of a pilot plant-scale hybrid anaerobic labyrinth-flow bioreactor (AL-FB) to increase the efficiency of anaerobic biodegradation and biogas productivity and improve anaerobic microflora performance. In addition, effluent recirculation was used to boost the treatment of dairy wastewater. Metagenomic analyses of the anaerobic microbial community were performed. It was found that an organic loading rate (OLR) of 4.0–8.0 g COD/L·d contributed to the highest CH4 yield of 0.18 ± 0.01–0.23 ± 0.02 L CH4/g COD removed, which corresponded to a high COD removal of 87.5 ± 2.8–94.1 ± 1.3%. The evenest distribution of the microorganisms' phyla determined the highest biogas production. In all tested samples, Bacteroidetes and Firmicutes abundance was the highest, and Archaea accounted for about 4%. Metagenomic studies showed that methane was mainly produced in acetoclastic methanogenesis; however, higher OLRs were more favorable for enhanced hydrogenotrophic methanogenesis. Effluent recirculation enhanced the overall treatment. Thus, at OLR of 10.0 g COD/L·d, the highest COD removal was 89.2 ± 0.4%, and methane production yield achieved 0.20 ± 0.01 L CH4/g COD removed, which was higher by 25% compared to the achievements without recirculation. [ABSTRACT FROM AUTHOR]

Methane pyrolysis is a transitional technology for environmentally benign hydrogen production with zero greenhouse gas emissions, especially when concentrated solar energy is the heating source for supplying high-temperature process heat. This study is focused on solar methane pyrolysis as an attractive decarbonization process to produce both hydrogen gas and solid carbon with zero CO2 emissions. Direct normal irradiance (DNI) variations arising from inherent solar resource variability (clouds, fog, day-night cycle, etc.) generally hinder continuity and stability of the solar process. Therefore, a novel hybrid solar/electric reactor was designed at PROMES-CNRS laboratory to cope with DNI variations. Such a design features electric heating when the DNI is low and can potentially boost the thermochemical performance of the process when coupled solar/electric heating is applied thanks to an enlarged heated zone. Computational fluid dynamics (CFD) simulations through ANSYS Fluent were performed to investigate the performance of this reactor under different operating conditions. More particularly, the influence of various process parameters including temperature, gas residence time, methane dilution, and hybridization on the methane conversion was assessed. The model combined fluid flow hydrodynamics and heat and mass transfer coupled with gas-phase pyrolysis reactions. Increasing the heating temperature was found to boost methane conversion (91% at 1473 K against ~100% at 1573 K for a coupled solar-electric heating). The increase of inlet gas flow rate Q0 lowered methane conversion since it affected the gas space-time (91% at Q0 = 0.42 NL/min vs. 67% at Q0 = 0.84 NL/min). A coupled heating also resulted in significantly better performance than with only electric heating, because it broadened the hot zone (91% vs. 75% methane conversion for coupled heating and only electric heating, respectively). The model was further validated with experimental results of methane pyrolysis. This study demonstrates the potential of the hybrid reactor for solar-driven methane pyrolysis as a promising route toward clean hydrogen and carbon production and further highlights the role of key parameters to improve the process performance. [ABSTRACT FROM AUTHOR]

Increasing worldwide milk manufacturing and dairy processing resulted in producing more effluents, and thus effective management of wastewater is now the most important issue. This study used a new design of a pilot plant-scale hybrid anaerobic labyrinth-flow bioreactor (AL-FB) to increase the efficiency of anaerobic biodegradation and biogas productivity and improve anaerobic microflora performance. In addition, effluent recirculation was used to boost the treatment of dairy wastewater. Metagenomic analyses of the anaerobic microbial community were performed. It was found that an organic loading rate (OLR) of 4.0–8.0 g COD/L·d contributed to the highest CH4 yield of 0.18 ± 0.01–0.23 ± 0.02 L CH4/g COD removed, which corresponded to a high COD removal of 87.5 ± 2.8–94.1 ± 1.3%. The evenest distribution of the microorganisms’ phyla determined the highest biogas production. In all tested samples, Bacteroidetes and Firmicutes abundance was the highest, and Archaea accounted for about 4%. Metagenomic studies showed that methane was mainly produced in acetoclastic methanogenesis; however, higher OLRs were more favorable for enhanced hydrogenotrophic methanogenesis. Effluent recirculation enhanced the overall treatment. Thus, at OLR of 10.0 g COD/L·d, the highest COD removal was 89.2 ± 0.4%, and methane production yield achieved 0.20 ± 0.01 L CH4/g COD removed, which was higher by 25% compared to the achievements without recirculation.

Methane pyrolysis is a transitional technology for environmentally benign hydrogen production with zero greenhouse gas emissions, especially when concentrated solar energy is the heating source for supplying high-temperature process heat. This study is focused on solar methane pyrolysis as an attractive decarbonization process to produce both hydrogen gas and solid carbon with zero CO2 emissions. Direct normal irradiance (DNI) variations arising from inherent solar resource variability (clouds, fog, day-night cycle, etc.) generally hinder continuity and stability of the solar process. Therefore, a novel hybrid solar/electric reactor was designed at PROMES-CNRS laboratory to cope with DNI variations. Such a design features electric heating when the DNI is low and can potentially boost the thermochemical performance of the process when coupled solar/electric heating is applied thanks to an enlarged heated zone. Computational fluid dynamics (CFD) simulations through ANSYS Fluent were performed to investigate the performance of this reactor under different operating conditions. More particularly, the influence of various process parameters including temperature, gas residence time, methane dilution, and hybridization on the methane conversion was assessed. The model combined fluid flow hydrodynamics and heat and mass transfer coupled with gas-phase pyrolysis reactions. Increasing the heating temperature was found to boost methane conversion (91% at 1473 K against ~100% at 1573 K for a coupled solar-electric heating). The increase of inlet gas flow rate Q0 lowered methane conversion since it affected the gas space-time (91% at Q0 = 0.42 NL/min vs. 67% at Q0 = 0.84 NL/min). A coupled heating also resulted in significantly better performance than with only electric heating, because it broadened the hot zone (91% vs. 75% methane conversion for coupled heating and only electric heating, respectively). The model was further validated with experimental results of methane pyrolysis. This study demonstrates the potential of the hybrid reactor for solar-driven methane pyrolysis as a promising route toward clean hydrogen and carbon production and further highlights the role of key parameters to improve the process performance.

Mass production of microorganisms, algae among them, for new bioactive compounds and renewable innovative products is a current issue in biotechnology. The greatest challenge of basic research on this topic is to find the best solution for both physiology and scalability. In this study, the main goal was to highlight the contradictions of physiological and technological optimization in the same, relatively small, laboratory scale. The green alga Monoraphidium pusillum (Printz) Komárková-Legnorová was cultured in a conventional Erlenmeyer flask (as air bubbled in a tank-type photobioreactor) and in a hybrid (fermenter type + helical tubular type) photobioreactor of the same volume (2.8 L). Higher cell numbers from 1.7–2.3-fold, 2–2.8-fold higher dry masses, and 1.9–2.6-fold higher total lipid contents (mg·L−1) were measured in the tank reactor than in the hybrid reactor. Cultures in the conventional tank reactor were characterized with better nutrient utilization (42.8–77.7% higher phosphate uptake) and more diverse lipid composition than in the hybrid reactor. The study highlights that well-scalable arrangements and settings could be not optimal (or unsuitable in some cases) from a physiological point of view. The results suggest certain developmental directions for complex, well-scalable devices and highlight the importance of testing the gained physiological optima on these systems. [ABSTRACT FROM AUTHOR]

Mass production of microorganisms, algae among them, for new bioactive compounds and renewable innovative products is a current issue in biotechnology. The greatest challenge of basic research on this topic is to find the best solution for both physiology and scalability. In this study, the main goal was to highlight the contradictions of physiological and technological optimization in the same, relatively small, laboratory scale. The green alga Monoraphidium pusillum (Printz) Komárková-Legnorová was cultured in a conventional Erlenmeyer flask (as air bubbled in a tank-type photobioreactor) and in a hybrid (fermenter type + helical tubular type) photobioreactor of the same volume (2.8 L). Higher cell numbers from 1.7–2.3-fold, 2–2.8-fold higher dry masses, and 1.9–2.6-fold higher total lipid contents (mg·L−1) were measured in the tank reactor than in the hybrid reactor. Cultures in the conventional tank reactor were characterized with better nutrient utilization (42.8–77.7% higher phosphate uptake) and more diverse lipid composition than in the hybrid reactor. The study highlights that well-scalable arrangements and settings could be not optimal (or unsuitable in some cases) from a physiological point of view. The results suggest certain developmental directions for complex, well-scalable devices and highlight the importance of testing the gained physiological optima on these systems.

Abstract A complete graphical solution is obtained for the completely mixed biofilm-activated sludge reactor (hybrid reactor). The solution consists of a series of curves deduced from the principal equations of the hybrid system after converting them in dimensionless form. The curves estimate the basic parameters of the hybrid system such as suspended biomass concentration, sludge residence time, wasted mass of sludge, and food to biomass ratio. All of these parameters can be expressed as functions of hydraulic retention time, influent substrate concentration, substrate concentration in the bulk, stagnant liquid layer thickness, and the minimum substrate concentration which can maintain the biofilm growth in addition to the basic kinetics of the activated sludge process in which all these variables are expressed in a dimensionless form. Compared to other solutions of such system these curves are simple, easy to use, and provide an accurate tool for analyzing such system based on fundamental principles. Further, these curves may be used as a quick tool to get the effect of variables change on the other parameters and the whole system.

The combination of photocatalysis and membrane filtration in a single reactor has been proposed, since the photocatalytic treatment may degrade the pollutants retained by the membrane and reduce fouling. However, polymeric membranes can be susceptible to degradation by UV radiation and free radicals. In the present study, five commercial polymeric membranes were exposed to ultraviolet (UV) radiation before and after applying a sol–gel coating with TiO2 nanoparticles. Membrane stability was characterized by changes in hydrophilicity as well as analysis of soluble substances and nanoparticles detached into the aqueous medium, and by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), and energy-dispersive X-ray spectrometry (EDS) for structural, morphological, and elemental distribution analysis, respectively. The TiO2 coating conferred photocatalytic properties to the membranes and protected them during 6 h of UV radiation exposures, reducing or eliminating chemical and morphological changes, and in some cases, improving their mechanical resistance. A selected commercial nanofiltration membrane was coated with TiO2 and used in a hybrid reactor with a low-pressure UV lamp, promoting photocatalysis coupled with cross-flow filtration in order to remove 17α-ethinylestradiol spiked into an aqueous matrix, achieving an efficiency close to 100% after 180 min of combined filtration and photocatalysis, and almost 80% after 90 min.

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The current research evaluates the treatment of Reactive Red 241, an anionic textile dye, by electro coagulation/biosorption (EC/BS) coupled process in a new hybrid reactor. The composite biomass pellets, suspended in the reactor using a twin rotary bucket system, were exploited as biosorbent. The influencing operational parameters of current density, pH, biosorbent dosage, and initial dye concentration were elucidated for decolorization. An effective performance of hybrid reactor resulted in complete decolorization with lower energy requirement and operational cost. At optimum conditions, color removal efficiency of 99.56% was obtained after 20 min at current density 21.7 mA/cm2, pH 7, biosorbent dosage 8 g/L, and dye concentration 50 mg/L with specific electrical energy consumption of 1.7 kWh/kg dye, and operational cost of 0.307 $/kg dye. The results indicate the potential of electro coagulation/biosorption (EC/BS) coupled hybrid reactor for the effective treatment of colored effluents. [ABSTRACT FROM AUTHOR]

The purpose of the study is to evaluate the efficiency of removing organic pollutants from wastewater in a household wastewater treatment plant with a hybrid reactor. The efficiency of the plant was analysed in terms of decreasing BOD5, COD and the content of total suspended solids in differentiated technological conditions. The variable parameter was the length of the reactor aeration phase and the dwell phase. Six different aeration variants were analysed. The efficiency of a wastewater treatment plant with a hybrid reactor in terms of reducing BOD5 oscillated from 81 to 90%, COD – 64–84%, whereas total suspended solids – 66–89% which, as a rule, was not sufficient to achieve standard levels. The best results were achieved for the following variants: 2h aeration – 2h dwell and 1h aeration – 0.5h dwell. Lower efficiency of the plant could have been attributed to operational problems, mainly failures of the plant control system and uneven conditions such as air temperature, volume and composition of wastewater received in the plant.

Graphical abstract Highlights • Highest nitrogen removal was achieved at 20 °C in the hybrid CANON reactor. • Performance was not always deteriorated with temperature reduction. • Activities of key enzymes were analyzed with temperature reduction. • The factors for maintaining nitrogen removal performance varied with temperature. Abstract Recently, a flocculent-granular hybrid reactor was reported as a novel nitrogen removal system; however, the mechanisms of stable operation in the system remain unclear. In this study, the mechanisms of the stable nitrogen removal performance in a flocculent-granular hybrid system were investigated with temperature reduction. The operational period was divided into three phases with different temperatures ranges. In phase I, the nitrogen removal efficiency was stabilized at about 90% with nitrogen removal load maintained at approximately 0.28 kg N/(m3·day). In phase II, while decreasing the temperature to 20 °C, the activities of key enzymes were reduced immediately and were then maintained at a certain level. The relative abundances of aerobic ammonium-oxidizing bacteria and anaerobic ammonium-oxidizing bacteria gradually increased at this phase. In phase III, after the temperature dropped to 15 °C, the activities of key enzymes gradually increased due to adaptation to low temperature, boosting the nitrogen removal efficiency to 83%. [ABSTRACT FROM AUTHOR]

In this study, anaerobic hybrid membrane bioreactor (An-HMBR) was operated for the treatment of synthetic leachate combining suspended growth, attached growth system and membrane system integrated in single unit. The treatment efficiency was examined under different ratios of synthetic leachate along with enrichment feed. Ammonia nitrogen (NH4-N) removal was limited compared to COD degradation due to anaerobic condition. The aim of the study is to examine nitrogen dynamics in An-HMBR and inhibition effect of NH4-N on the COD removal percentage. The nitrogen loading rate increased from 0.12 to 1.27 kg/m3 day and NH4-N concentration increased from 250 to 2500 mg L−1. The results showed that lower NH4-N concentration does not affect COD removal efficiency, while with increase in NH4-N concentration the COD removal efficiency decreased from 96 to 82%. The process inhibition of ammonia nitrogen was evaluated by Monod, Yano-Koga and Haldane model. Among the inhibition models, Yano-Koga model showed best fit correlation coefficient (R2 0.97) compared to other models. High concentration of ammoniacal nitrogen reduces the COD removal efficiency. Mass balance study shows that accumulation of ammoniacal nitrogen takes place at high leachate concentration. Yano-Koga model describes the specific growth rate very well. The maximum specific growth rate was 0.006 h−1 and substrate inhibition constant was 761. [ABSTRACT FROM AUTHOR]

Abstract Outcomes from RFX-mod, the largest Reversed Field Pinch (RFP) experiment, have shown a substantial increase of the electron and ion temperatures versus the plasma current with a trend that allows hypothesizing significant D-T fusion processes in larger devices with higher plasma current. Such a device, in which the plasma is purely ohmically heated, could act as an efficient, robust and cheap fusion neutron source with a neutron rate to be used as the basis for a Fusion-Fission Hybrid Reactor (FFHR). The peculiar features of this neutron source can be summarized as: ohmically heated plasma, toroidal field winding rated for a low magnetic field (one-two orders of magnitude lower than in Tokamaks), very simple, robust and cheap construction, simple access for Remote Handling and easy maintenance. Almost continuous neutron production, as required in a hybrid reactor, is guaranteed by a continuously pulsed operation without the need of additional current drive systems. The aim of the paper is to investigate the relationship between the machine size (major and minor device radius), the attainable stored volt-seconds and, consequently, the maximum plasma current and pulse duration. The analysis uses the experimental RFX-mod data (electron temperatures, plasma currents, loop voltages during flat top) to extrapolate the performances of larger RFP devices with significant neutron production from D-T reactions. This study shows a realistic possibility, in an inductively operated RFP of larger size than RFX-mod, with plasma current 15–20 MA and temperature ≈ 10–15 keV, to reach the level of neutron generation of a fusion-fission hybrid reactor, leading to a neutron production rate in the range of 1019 n/s and a wall neutron load of 0.2 MW/m2. [ABSTRACT FROM AUTHOR]

Abstract To investigate the compatibility and diffusion behavior between U-Zr alloys and Zr-4 alloys, solid-to-solid U-10wt% Zr/Zr-4 diffusion couples were assembled by vacuum hot pressing and then annealed under vacuum at temperatures ranging from 580 °C to 1100 °C for various time. Scanning and transmission electron microscopes were employed to analyze the microstructures and composition profiles at the interfaces of the couples. The compatibility between the two alloys was investigated. δ -UZr 2 and ∼20-nm-thin U-rich layers existed in the vacuum-hot-pressed samples. The interdiffusion coefficient constant and activation energy are found to be (4.23±0.63)×10−6 m2/s and (160.73±1.67) kJ/mol, respectively. The interdiffusion coefficients of the U-10wt% Zr/Zr-4 alloy couples are higher than those of U—Zr alloys, especially at low temperature. [ABSTRACT FROM AUTHOR]

Up today, two hyper research projects to achieve nuclear fusion energy exist; inertial confinement fusion (ICF) driven by laser, called national ignition facility (NIF) and magnetic confinement fusion the international thermonuclear experimental reactor (ITER) project. In reaching the required temperature and pressure, to ignite nuclear fusion reactor, is technologically complex and economically expensive. Thus, a breakthrough and a short cut, other alternative methods should be considered. Pulsed power ICF driver with repetitive pulse operation, mainly dense plasma focus (DPF) machines for high yield fusion neutrons could be taken as drivers for the fission blanket operation. The setup can be a cost-effective and efficient. In this article, we consider a set of two medium energy sizes DPF to produce simultaneously dense plasma columns, operating as thermonuclear plasma driver, to pierce the pellet target for external nuclear fusion reactions. These DPFs produce sufficient fast neutrons for the fission process in the neutral uranium or thorium and/or weak enriched uranium blanket. The drive systems and the concept for delivering thermonuclear plasma to pellets target in the magnetic free zone of central region will be presented. The feasibility of such fusion-fission hybrid reactor will be discussed. [ABSTRACT FROM AUTHOR]

A hybrid upflow anaerobic sludge blanket (UASB)–moving bed biofilm (MBB) and rope bed biofilm (RBB) reactor was designed for treatment of sewage. Possibility of enhancing granulation in an UASB reactor using moving media to improve sludge retention was explored while treating low-strength wastewater. The presence of moving media in the top portion of the UASB reactor allowed a high solid retention time even at very short hydraulic retention times and helped in maintaining selection pressure in the sludge bed to promote formation of different sized sludge granules with an average settling velocity of 67 m/h. These granules were also found to contain plenty of extracellular polymeric substance (EPS) such as 58 mg of polysaccharides (PS) per gram of volatile suspended solids (VSS) and protein (PN) content of 37 mg/g VSS. Enriched sludge of nitrogen-removing bacteria forming a porous biofilm on the media in RBB was also observed in a concentration of around 894 g/m2. The nitrogen removing sludge also had a high EPS content of around 22 mg PS/g VSS and 28 mg PN/g VSS. This hybrid UASB-MBB-RBB reactor with enhanced anaerobic granular sludge treating both carbonaceous and nitrogenous matter may be a sustainable solution for decentralized sewage treatment. [ABSTRACT FROM PUBLISHER]

A new hybrid photocatalytic membrane reactor that can easily be scaled-up was designed, assembled and used to test photocatalytic membranes developed using the sol−gel technique. Extremely high removals of total suspended solids, chemical oxygen demand, total organic carbon, phenolic and volatile compounds were obtained when the hybrid photocatalytic membrane reactor was used to treat olive mill wastewaters. The submerged photocatalytic membrane reactor proposed and the modified membranes represent a step forward towards the development of new advanced treatment technology able to cope with several water and wastewater contaminants.

The aim of this work is to contribute for the scientific advancement of carbon capture and utilization technologies (CCU), while exploring the integration of intermittent renewable electricity production and substitute natural gas (SNG) production, the so-called “Power-to-Gas” concept. In this regard, a sorptive reactor for carrying in the same unit both CO 2 capture and conversion to SNG using renewable H 2 was studied, in a perspective of process intensification. The sorptive reactor containing a layered bed of a K-promoted hydrotalcite to capture CO 2 by sorption (step 1) and a nickel-based catalyst for CO 2 hydrogenation (step 2) is operated at 300–350 °C and low pressure (≤2.5 bar). Integration of CO 2 capture and conversion in the same unit leads to enhanced sorption capacities and desorption kinetics promoted by the steam produced in situ during the reactive regeneration stage (methanation reaction). The sorptive reactor working under continuous operation mode allows to: i) capture ca . 0.30 mol of CO 2 per kilogram of sorbent and per sorption cycle, at 350 °C and p CO 2 = 0.2 bar; ii) completely convert the captured CO 2 into CH 4 ; iii) reach a productivity of ca . 2.36 mol CH 4 · kg cat - 1 · h - 1 ; iv) avoid CO formation at 300 °C and 1.34 bar and v) reach a CH 4 purity of 35% at 350 °C after N 2 purge. [ABSTRACT FROM AUTHOR]

Hybrid reactor of Dielectric Barrier Discharge (DBD) and Solid Oxide Electrolyser Cell (SOEC) was fabricated and CO2 decomposition characteristics were investigated. For the case of the DBD reactor alone, the CO2 conversion saturates with residence time. In contrast, the saturation is not observed for the case of the hybrid system where CO2 conversion increases monotonically with increasing residence time. This is because the reverse reaction to regenerate the CO2 in plasma is suppressed by the oxygen removal by SOEC in hybrid system and consequently CO2 decomposition reaction proceeds irreversibly. We have examined the experimental results by analytical modeling and reaction mechanism for the CO2 decomposition in the hybrid reactor of DBD and SOEC is deduced. The time-dependent CO2 conversion for the only plasma reactor and hybrid reactor can be reproduced by a reversible and irreversible first-order reaction model, respectively. The analytical model can also reproduce the dependence of CO2 conversion on the plasma input power very well. Interestingly, not only the reverse reaction rate but also the forward dissociation reaction rate is reduced by the SOEC in the case of hybrid reactor. The analytical modeling suggests that CO2 decomposition in the conventional DBD plasma reactor proceeds not merely by direct electron impact dissociation but also by reaction with reactive oxygen. [ABSTRACT FROM AUTHOR]

The present study deals with development of a hybrid reactor for biodiesel production based on the combined hydrodynamic cavitation and mechanical stirring processes. Biodiesel were produced using Kaner Seed Oil (KSO). The experimental results show that hybrid reactor produces 95% biodiesel yield within 45 min for 0.75% of catalyst and 6:1 M ratio which is significantly higher as compared to mechanical stirring or hydrodynamic cavitation alone. Thus biodiesel production process in hybrid reactor is cheap (high yield), efficient (time saving) and environmentally friendly (lower% of catalyst). Performance study on engine shows that an increase in compression ratios (from 16 to 18) improves the engine performance using biodiesel blends as compared to petroleum diesel. [ABSTRACT FROM AUTHOR]

This study aimed to investigate potential methane production through anaerobic digestion of dairy manure and co-digestion with maize silage. Two different anaerobic reactor configurations (single-stage continuously stirred tank reactor [CSTR] and hybrid anaerobic digester) were used and biogas production performances for each reactor were compared. The HR was planned to enable phase separation in order to improve process stability and biogas production under higher total solids loadings (≥4%). The systems were tested under six different organic loading rates increased steadily from 1.1 to 5.4 g VS/L.d. The CSTR exhibited lower system stability and biomass conversion efficiency than the HR. The specific biogas production of the hybrid system was between 440 and 320 mL/gVS with 81-65% volatile solids (VS) destruction. The hybrid system provided 116% increase in specific biogas production and VS destruction improved by more than 14%. When MS was co-digested together with dairy manure, specific biogas production rates increased about 1.2-fold. Co-digestion was more beneficial than mono-material digestion. The hybrid system allowed for generating methane enriched biogas (>75% methane) by enabling phase separation in the reactor. It was observed that acidogenic conditions prevailed in the first two compartments and the following two segments as methanogenic conditions were observed. The pH of the acidogenic part ranged between 4.7 and 5.5 and the methanogenic part was between 6.8 and 7.2. [ABSTRACT FROM AUTHOR]

A hybrid anaerobic reactor with built-in bioelectrochemical system (BES) has been verified for efficiently treating mixed azo dye wastewater, yet still facing many challenges, such as uncertain reactor construction and insufficient electron donors. In this study, an up-flow hybrid anaerobic reactor with built-in BES was developed for acid orange 7 (AO7) containing wastewater treatment. Cathode and real domestic wastewater both served as electron donor for driving azo dye decolorization. The decolorization efficiency (DE) of AO7 (200 mg/L) in the hybrid reactor was 80.34 ± 2.11% with volume ratio between anaerobic sludge and cathode (VR slu:cat ) of 0.5:1 and hydraulic retention time (HRT) of 6 h, which was 15.79% higher than that in BES without sludge zone. DE was improved to 86.02 ± 1.49% with VR slu:cat increased to 1:1. Further increase in the VR slu:cat to 1.5:1 and 2:1, chemical oxygen demand (COD) removal efficiency was continuously improved to 28.78 ± 1.96 and 32.19 ± 0.62%, but there was no obvious DE elevation (slightly increased to 87.62 ± 2.50 and 90.13 ± 3.10%). BES presented efficient electron utilization, the electron usage ratios (EURs) in which fluctuated between 11.02 and 13.06 mol e − /mol AO7. It was less than half of that in sludge zone of 24.73–32.06 mol e − /mol AO7. The present work optimized the volume ratio between anaerobic sludge and cathode that would be meaningful for the practical application of this hybrid system. [ABSTRACT FROM AUTHOR]

The study describes developing an energy-efficient and scalable alternative to conventional non-thermal plasma systems by integrating surface dielectric barrier discharge (SDBD) and UV-C radiation sources. The unprecedented enhancement in the mineralisation rate of an azo dye (brilliant red 5B) by the hybrid reactor (photo-SDBD) is demonstrated thoroughly as a function of dye concentrations, pH, and background salts. The photo-SDBD is 1.25 – 4.9 times more energy efficient than SDBD under similar experimental conditions. The photo-SDBD could overcome the problems such as the recombination of hydroxyl radicals and scavenging of radicals by salts (NaCl, Na 2 SO 4 , Na 2 CO 3) observed in conventional non-thermal plasma systems. The TOC and HR-MS analysis establish the complete mineralisation potential and chemical mineralisation pathway. Besides, the phytotoxicity of the treated water is tested and demonstrated its utility as a liquid fertiliser for enhanced germination of mung bean seeds. The optical emission spectroscopy measurements were performed to estimate the plasma's electron temperature (1.6 ± 0.2 eV) and density (1021/m3). The emission line ratio (I 763.5 /I 738.3) approach is used to compare the influence of UV-C on plasma parameters in the SDBD reactor. The study opens a new pathway for developing energy-efficient and scalable plasma-assisted mineralisation of complex and emerging organic pollutants. [Display omitted] • Developed a novel Photo-SDBD hybrid reactor for rapid mineralization of aqueous dye • A new strategy to minimize recombination of •OH and scavenging effect • The superiority of photo-SDBD over SDBD under various conditions is demonstrated • The dye degradation pathway and effluent phototoxicity are studied • A new method is proposed to use treated effluent as a liquid fertiliser [ABSTRACT FROM AUTHOR]

The paper describes the concept of a deuterium-tritium fuel cycle of a steady-state thermonuclear reactor with a fusion power over 10 MW. Parameters of fuel cycle for nuclear facility (JET scale) with different types of fuel mixtures for neutral beam injection system are presented. Optimization of fuel cycle characteristics was aimed at reducing flows and inventory of hydrogen isotopes and tritium in fuel cycle subsystems. The calculations were carried out using computer code TC-FNS to estimate tritium distribution in fusion reactor systems and components of “tritium plant”. The code enables calculations of tritium flows and inventory in the tokamak systems. Calculations of tritium flows and accumulation have been carried out for two different cases of the fuel mixture for neutral beam injection (NBI) system. The amounts of tritium which is required for operation of all fuel cycle systems in two different cases of the fuel mixture for NBI are 0.45 “” kg (D:T = 1:0) and 0.9 kg (D:T = 1:1) respectively. [ABSTRACT FROM AUTHOR]

The purpose of the study is to evaluate the efficiency of removing organic pollutants from wastewater in a household wastewater treatment plant with a hybrid reactor. The efficiency of the plant was analysed in terms of decreasing BOD5, COD and the content of total suspended solids in differentiated technological conditions. The variable parameter was the length of the reactor aeration phase and the dwell phase. Six different aeration variants were analysed. The efficiency of a wastewater treatment plant with a hybrid reactor in terms of reducing BOD5 oscillated from 81 to 90%, COD - 64-84%, whereas total suspended solids -- 66--89% which, as a rule, was not sufficient to achieve standard levels. The best results were achieved for the following variants: 2h aeration -- 2h dwell and 1h aeration -- 0.5h dwell. Lower efficiency of the plant could have been attributed to operational problems, mainly failures of the plant control system and uneven conditions such as air temperature, volume and composition of wastewater received in the plant. [ABSTRACT FROM AUTHOR]

The small wastewater treatment plant is a device or group of devices which—through mechanical, biological, and chemical processes—reduces the pollution load to the values specified in the Regulation of the Minister of the Environment. The aim of this research is to show the relationship between the growth of the biomass and the effectiveness of removing contaminants from wastewater in individual wastewater treatment systems. The results of activated sludge volume after 30 min settling, microscopic analysis, and quantitative and qualitative parameters of biomass in the aeration chambers were analyzed in this article. During the research, one of the reactors was converted into a hybrid reactor (SBR filled with plastic carriers, which support the process of nitrification). A microscopic analysis of the biomass was conducted to evaluate the operation of activated sludge and biofilm. Flocs of activated sludge in the SBR were characterized by irregular shape and high biodiversity. The appearance of rotifers testified about the good condition of the sludge. The microscopic analysis of biomass of the hybrid reactor showed a negative effect of the applied biopreparation. Microorganisms such as bacteria and ciliates were observed in the biomass. In summary, the structure of the biofilm and activated sludge floc is very sensitive to the system parameters and external factors. Biofilm develops more slowly than the activated sludge. Introduction of the moving bed into the reactor of activated sludge should be made in the summertime. [ABSTRACT FROM PUBLISHER]

We report, for the first time, extensive biologically-mediated phosphate removal from wastewater during high-rate anaerobic digestion (AD). A hybrid sludge bed/fixed-film (packed pumice stone) reactor was employed for low-temperature (12°C) anaerobic treatment of synthetic sewage wastewater. Successful phosphate removal from the wastewater (up to 78% of influent phosphate) was observed, mediated by biofilms in the reactor. Scanning electron microscopy and energy dispersive X-ray analysis revealed the accumulation of elemental phosphorus (~2%) within the sludge bed and fixed-film biofilms. 4’, 6-diamidino-2-phenylindole (DAPI) staining indicated phosphorus accumulation was biological in nature and mediated through the formation of intracellular inorganic polyphosphate (polyP) granules within these biofilms. DAPI staining further indicated that polyP accumulation was rarely associated with free cells. Efficient and consistent chemical oxygen demand (COD) removal was recorded, throughout the 732-day trial, at applied organic loading rates between 0.4-1.5 kg COD m-3 d-1 and hydraulic retention times of 8-24 hours, while phosphate removal efficiency ranged from 28-78% on average per phase. Analysis of protein hydrolysis kinetics and the methanogenic activity profiles of the biomass revealed the development, at 12˚C, of active hydrolytic and methanogenic populations. Temporal microbial changes were monitored using Illumina Miseq analysis of bacterial and archaeal 16S rRNA gene sequences. The dominant bacterial phyla present in the biomass at the conclusion of the trial were the Proteobacteria and Firmicutes and the dominant archaeal genus was Methanosaeta. Trichococcus and Flavobacterium populations, previously associated with low temperature protein degradation, developed in the reactor biomass. The presence of previously characterised polyphosphate accumulating organisms (PAOs) such as Rhodocyclus, Chromatiales, Actinobacter and Acinetobacter was recorded at low numbers. However, it is unknown as yet if these were responsible for the luxury polyP uptake observed in this system. The possibility of efficient phosphate removal and recovery from wastewater during AD would represent a major advance in the scope for widespread application of anaerobic wastewater treatment technologies.

Nitrate in the groundwater can cause a number of health and environmental issues. Therefore, a novel denitrifying reactor was investigated regarding rapid granulation of biomass and reactor start-up. The effects of the wastewater characteristics, reactor operating conditions, and reactor geometry on microbial granulation were studied. It was possible to achieve granulation in just 15 days of reactor start-up. In 15 days, the settling velocity of the granules was almost tenfold higher than that of seed sludge. The reactor was able to handle a nitrate loading rate of 460 g NO3-N m−3d−1 in just 30 days of reactor start-up, with a removal efficiency of almost 100 %. Based on the experimental observations, a hypothesis for the cause of the rapid granulation is proposed. [ABSTRACT FROM AUTHOR]