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Straw biochar prepared by three methods (i.e., pyrochar, HNO3-modified pyrochar, and hydrochar) was added to the anaerobic digestion system with acetic acid and ethanol as substrates to explore the effects of biochar on methane production, substrate degradation, and microbial community structure. The biogas yields of the biochar-supplemented groups all increased, and the maximum methane yield was found in the hydrochar group, which was 45.4% higher than the control. In the ethanol-fed reactor, the maximum partial pressure of hydrogen in the headspace of the hydrochar reactor was reduced from 3.5% (blank reactor) to 1.9%. Overall, methane production is directly proportional to the electron exchange capacity (EEC) value of biochar. Furthermore, the bio-aging process increased the EEC of each kind of biochar to 5.5–8.1%, which was favorable for the sustainable promotion of methanogenesis. The increased methane yield from the bio-aged biochar could either be attributable to the changes in surface oxygen-containing functional groups or the selectively enriched microbial community on the biochar, such as Geobacter, which could participate in direct interspecies electron transfer.

Purpose: Hearing assistive technology (HAT) has been shown to be a viable solution to the speech-in-noise perception (SPIN) issue in children with autism spectrum disorder (ASD); however, little is known about its efficacy in tonal language speakers. This study compared sentence-level SPIN performance between Chinese children with ASD and neurotypical (NT) children and evaluated HAT use in improving SPIN performance and easing SPIN difficulty. Methods: Children with ASD (n=26) and NT children (n=19) aged 6-12 performed two adaptive tests in steady-state noise and three fixed-level tests in quiet and steady-state noise with and without using HAT. Speech recognition thresholds (SRT) and accuracy rates were assessed using adaptive and fixed-level tests, respectively. Parents or teachers of the ASD group completed a questionnaire regarding children’s listening difficulty under six circumstances before and after a ten-day trial period of HAT use. Results: Although the two groups of children had comparable SRTs, the ASD group showed a significantly lower SPIN accuracy rate than the NT group. Also, a significant impact of noise was found in the ASD group’s accuracy rate, but not in the NT group’s. There was a general improvement in the ASD group’s SPIN performance with HAT and a decrease in their listening difficulty ratings across all conditions after the device trial. Conclusion: The findings indicated inadequate SPIN in the ASD group using a relatively sensitive measure to gauge SPIN performance among children. The markedly increased accuracy rate in noise during HAT-on sessions for the ASD group confirmed the feasibility of HAT for improving SPIN performance in controlled laboratory settings, and the reduced post-use ratings of listening difficulty further confirmed the benefits of HAT use in daily scenarios.

The annual increase of waste activated sludge (WAS) has become an urgent problem to be solved in sewage plants worldwide. Anaerobic digestion (AD) of WAS is an attractive choice to maximize the resource utilization rate. Nevertheless, the disintegration of sludge complex polymers is difficult, resulting in low bioconversion rate. Potassium ferrate (PF), as a green oxidant with strong oxidizing property, has been attracted great attention in WAS pretreatment recently. The effects of PF pretreatment on WAS hydrolysis and its dosage-response on methane production were investigated in the present study. Results show that as PF dosage raise from 0 to 50 g-K

In this study, exogenous Megasphaera elsdenii inoculum and acetate supplementation were introduced at the acidogenic phase to regulate the acidogenic fermentation pathway and assess their effects on food waste (FW) carbon conversion in two-phase anaerobic digestion (AD) system. These two additives significantly accelerated organic removal efficiency and subsequently increased FW hydrolysis and acidogenesis by 16% and 35%, respectively. As expected, two exogenous additives promoted butyrate fermentation during FW acidogenesis. With regard to the role of exogenous additives, both hydrogen and butyrate yields increased by over 60%. This desired increment resulted in a 25% increase in methane production. The overall carbon conversion from FW in the integrated two-phase AD system was enhanced by biochemical additives, which was 1.3-fold higher than that in control without any additives. Collectively, findings demonstrate the feasibility of regulating acidogenic fermentation via exogenous biochemical additives and its benefits on FW carbon conversion during AD process.

Energy crisis and increasing rigorous management standards pose significant challenges for solid waste management worldwide. Several emerging diseases such as COVID-19 aggravated the already complex solid waste management crisis, especially sewage sludge and food waste streams, because of the increasingly large production year by year. As mature waste disposal technologies, landfills, incineration, composting, and some other methods are widespread for solid wastes management. This paper reviews recent advances in key sewage sludge disposal technologies. These include incineration, anaerobic digestion, and valuable products oriented-conversion. Food waste disposal technologies comprised of thermal treatment, fermentation, value-added product conversion, and composting have also been described. The hot topic and dominant research foci of each area are summarized, simultaneously compared with conventional technologies in terms of organic matter degradation or conversion performance, energy generation, and renewable resources production. Future perspectives of each technology that include issues not well understood and predicted challenges are discussed with a positive effect on the full-scale implementation of the discussed disposal methods.

To improve the dose efficiency of K

Hierarchical porous carbons (HPCs) with optimized porosity and enriched surface functional groups are a promising carbon material for supercapacitor development. However, it is a challenge to reali...

Suitable treatment of toilet sewage is a worldwide challenge. The anaerobic baffled reactor (ABR)-microbial fuel cell (MFC)-microbial electrolysis cell (MEC) (AMM) coupling treatment system has been constructed achieving effective removal of carbon, nitrogen, and phosphorus from toilet sewage and resource recovery; however, ammonium (NH4 + -N) and total phosphorus (TP) accumulation in tail water is a found problem of the system. In this study, acid-modified and alkali-heat modified palygorskite-bentonite (Pal-Ben) were used to recover NH4 + -N and TP from the AMM toilet tail water simultaneously. The higher adsorption capacity of the modified clay is attributed to the changes of surface structure of the material. The modified clay Pal-Ben (mass ratio 1:3) activated with alkali performed the highest NH4 + -N and TP recovery rates of 83.6% and 85.5%, respectively. The adsorption of NH4 + -N was more in line with the pseudo-second-order kinetic model and confirmed to be a chemical adsorption process, while the adsorption of TP was more in line with the pseudo-first-order kinetics and a physical adsorption process; the adsorption capacity of NH4 + -N accelerated with decrease of TP removal when pH increased. This study developed a low cost and high capacity of alkaline thermally modified clay removing/recovering NH4 + -N and TP from toilet tail water simultaneously. PRACTITIONER POINTS: A cheap composite clay was developed to recover nitrogen and phosphorus from toilet tail water simultaneously. The low costs and high capacity of alkaline thermally modified clay make it stand out in NH4 + -N and TP removal of toilet tail water. The process mechanism of simultaneous nitrogen and phosphorus recovery was clarified with characterization and kinetic model fitting. The used clay loaded with nutrients could be applied as a slow-release compound fertilizer for soil improvement.

International audience; Biochar addition to anaerobic digestion systems generally improves the conversion of organic waste into methane, yet biogas residues are still unwanted byproducts that may pollute the environment. Therefore, we hypothesized that biogas residues could be recycled into new biochar. We produced biochar by heating at 500 °C the residue of anaerobic digestion of food waste. We measured methane production by adding either this residue biochar, or coconut shell biochar, or corn stalk biochar, in the anaerobic codigestion of sewage sludge and food waste. Results show that the residue biochar produces the highest daily methane amount, of 432.2 mL per g of volatile solids, versus 377.7-386.3 mL for coconut and corn biochars. This finding is tentatively explained by the fact that the residue biochar has more basic groups, which neutralize fatty acids and, in turn, alleviates acidification. Another explanation is the higher abundance in sludge of electroactive Clostridia, Methanobacterium and Methanobrevibacter, which are known to accelerate methanation. Recyling biogas residues as biochar onsite would both decrease the amount of digestion byproducts and avoid long-distance transportation of biochar from remote biomass.

National audience; In order to improve the denitrification efficiency of low carbon to nitrogen ratio (C/N) wastewater, we conducted continuous flow experiments of weakly electrically stimulated denitrification using a direct current output voltage. The results showed that the best denitrification was achieved at a voltage of 0.2 V. The removal of nitrate and total nitrogen was increased by 20% and the production of intermediate greenhouse gas (N2O) was reduced by 62.6%. We explored the specific pathways involved in the weak electrical stimulated denitrification using enzyme activity as a cut-off point. The enzyme activity analysis and 3D fluorescence spectroscopy revealed that nitrate reductase (NAR) and nitrite reductase (NIR) activities were significantly enhanced by weak electrical stimulation, and the aromatic protein content in extracellular polymeric substances (EPS) increased, accelerating electron transfer and promoting the conversion of loosely bound EPS (LB) to tightly bound EPS (TB). The accelerated electron transfer further increased enzyme activity and the metabolic rate of microorganisms. This study indicates that weak electrical stimulation could improve activities of biological enzymes to enhance denitrification efficiency.

International audience; About 1.6 billion tons of food are wasted worldwide annually, calling for advanced methods to recycle food waste into energy and materials. Anaerobic digestion of kitchen waste allows the efficient recovery of energy, and induces low-carbon emissions. Nonetheless, digestion stability and biogas production are variables, due to dietary habits and seasonal diet variations that modify the components of kitchen waste. Another challenge is the recycling of the digestate, which could be partly solved by more efficient reactors of anaerobic digestion. Here, we review the bottlenecks of anaerobic digestion treatment of kitchen waste, with focus on components inhibition, and energy recovery from biogas slurry and residue. We provide rules for the optimal treatment of the organic fraction of kitchen waste, and guidelines to upgrade the anaerobic digestion processes. We propose a strategy using an anaerobic dynamic membrane bioreactor to improve anaerobic digestion of kitchen waste, and a model for the complete transformation and recycling of kitchen waste, based on component properties.

Wastewater treatment is an essential aspect of the earth's sustainable future. However, different wastewater treatment methods are responsible for carbon discharge into the environment, raising environmental risks. Hence, such wastewater treatment methods are required that can minimize carbon release without compromising the treatment quality. Microbiome-based carbon sequestration is a potential method for achieving this goal. Limited studies have been carried out to investigate how microbes can capture and utilize CO

Structural defects and surface functional groups defects engineering in the graphitic carbon nitride (g-C3N4) polymer semiconductor usually has great benefit in optimizing its electron structure and photocatalytic performance. In this study, one type of carboxyl group defects-grafting g-C3N4 was prepared through glucose oxidase treatment on the initial O sites in the g-C3N4, which played multi-functional roles in the generation of carboxyl groups and melon structure defect. FT-IR, XPS and 13C NMR analysis verified the presence of highly favorable carboxyl groups, which was beneficial to the fast separation and migration of photogenerated carriers. The singularity of enzyme mediated defects control of carbon nitride materials was greatly boosted on O-enriched g-C3N4 (OCN) further supporting the overall O sites ring-opening hypothesis. The glucose oxidase (GOD) treated reconstructed g-C3N4 photocatalysts showed narrowed band gaps and fast charge separation ability as verified by UV–vis DRS and electrochemical tests. As a result, the optimized photocatalyst (GOD-OCN-3d) showed a high Cr(VI) photocatalytic detoxification rate of 99 %, which was 6.6 times higher than that of raw g-C3N4 (15 %) in 120 min. These findings open the understanding on precise molecular defects modulation of g-C3N4 via an environmental-friendly enzyme treatment approach, as well as providing a new avenue for understanding the function of structural defects of photocatalysts on prompting charge separation.

In light of current globalization and economic regional integration, especially after the 18th National Congress of the Communist Party of China, college English teaching in China has become increasingly unable to meet the demand of building China into a cultural power. Based on computer corpora, the paper proposes how to build the cultural confidence of college students from the following four aspects: (1) to reform the current syllabus and curriculum; (2) to add the content of Chinese culture into college English textbooks; (3) to promote the cultural identity of English teachers; (4) to fully exert the guiding role of English proficiency tests.

The advantages of anaerobic digestion (AD) technology in organic solid waste treatment for bioenergy recovery are evidenced in worldwide. Recently, more attention has been paid to on-site biogas research, as well as biogenic CO2 sequestration from AD plant, to promote "carbon neutral". Single-phase and two-phase AD system can be incorporated with various CO2 bioconversion technologies through H2 mediated CO2 bioconversion (in-situ and ex-situ biogas upgrading), or other emerging strategies for CO2 fixation without exogenous H2 injection; these include in-situ direct interspecies electron transfer reinforcement, electromethanogenesis, and off-gas reutilization. The existing and potential scenarios for on-site CO2 bio-sequestration within the AD framework are reviewed from the perspectives of metabolic pathways, functional microorganisms, the limitations on reaction kinetics. This review concluded that on-site CO2 bio-sequestration is a promising solution to reduce greenhouse gas emissions and increase renewable energy recovery.

International audience; Wastewater microbial fuel cells (MFCs) can transform the chemical energy into electricity; however, little is known on the effect of circuit modes on start-up and performance of wastewater MFCs. Here we have investigated the effect of four circuit modes on start-up, performance and membrane fouling of MFCs systematically. Besides shortening the start-up period and improving the performance of MFCs, applying anodic negative potential also balances pH of the system and thus enhances COD removal. The open-circuit constant potential mode (OC-MFC) presents the shortest start-up period of 5 days, with the highest voltage output of 810 mV and the slightest membrane fouling, which provides an effectively strategy to accelerate the start-up of wastewater MFCs. The circuit mode applied to start up wastewater MFC not only affects the degree of membrane fouling, but also causes significant differences in anode microbial communities. The total abundance of exoelectrogens in the closed-circuit intermittent potential (CI-MFC) mode was the highest up to 54.70%, but the performance of CI-MFC inferiors to OC-MFC, indicating that performance of the wastewater MFC is not solely determined by the dominant bacteria. Overall, the OC-MFC provides a new strategy to accelerate the start-up period and enhance performance of wastewater MFC simultaneously.

International audience; Thermal/ultrasonic pre-treatment of sludge has been proven to break the hydrolysis barriers of sewage sludge (SS) and improve the performance of anaerobic digestion (AD). In this study, the objective was to investigate whether the combination of two pre-treatment methods can achieve better results on the AD of SS. The results indicated that, compared with the control group and separate pre-treatment groups, the thermal combined ultrasonic pre-treatment presented more obvious solubilization of soluble proteins, polysaccharides, and other organic matters in SS. The combined method promoted the dissolution of protein-like substances more effectively, with biogas production increased by 19% and the volatile solid (VS) removal rate improved to above 50% compared with the control group. The capillary suction time is reduced by about 85%, which greatly improved the dewatering performance of SS. In addition, the combined method has advantages in degrading sulfonamide antibiotics, roxithromycin and tetracycline. Particularly, by analyzing the interaction between the degradation of different antibiotics and the composition of dissolved organic matters (DOMs), it was found that the composition of DOMs could affect the degradability of different antibiotics. Among them, the high content of tyrosine-like and tryptophan-like was conducive to the degradation of sulfamethoxazole, and the high content of fulvic acid-like and humic acid-like was conducive to the degradation of roxithromycin and tetracycline. This work evaluated the comprehensive effect of thermal combined ultrasonic pre-treatment on SS disposal and provided useful information for its engineering.

Affective prosody recognition is an important area of research in autism spectrum conditions where difficulties in social cognition have been frequently observed. To probe into the mixed results reported in the literature, we conducted a systematic review with meta-analysis and examined potential factors that could explain the inconsistent results. Our literature search included six electronic databases for studies that compared the affective prosody recognition performance in individuals with autism spectrum condition with typically developing participants, which yielded 23 papers eligible for quantitative synthesis. Using a random-effects model, we obtained a moderate-to-large pooled effect (Hedges’ g = −0.63) for the overall affective prosody recognition performance of autism spectrum condition participants, which, however, reduced substantially (to −0.26) and became non-significant after the correction for publication bias. The number of answer codes was found to be a significant moderator for the effect estimate, whereas the number of speakers was not. Moreover, the magnitude of the pooled effect estimate varied across emotions. The findings suggested moderate differences in affective prosody recognition ability between autism spectrum condition and typically developing individuals, which reduced to marginal difficulties for autism spectrum condition when the impact of publication bias was taken into account. Diversity in the number of answer codes could have differential effects on affective prosody recognition performance in autism spectrum condition, which varied across emotions. The present review and meta-analysis demonstrated the insufficiency of research on affective prosody recognition in autism spectrum condition, highlighting a need for further exploration of the contributors and underlying mechanisms for specific affective prosody recognition difficulties. Lay abstract Differences in understanding others’ emotions and attitudes through features in speech (e.g. intonation) have been observed in individuals with autism spectrum conditions, which contribute greatly to their social communication challenges. However, some studies reported that individuals with autism spectrum condition performed comparably to typically developing individuals on affective prosody recognition. Here, we provide a comprehensive review with statistical analysis of 23 existing studies on this topic to examine potential factors that could explain the discrepancies. Compared with typically developing individuals, autism spectrum condition participants generally appeared to encounter more difficulties in affective prosody recognition. But this finding was likely due to the tendency of the existing research to overly focus on deficits in autism. The affective prosody recognition performance in individuals with autism spectrum condition was closely related to the number of answer options offered to them. Moreover, the degree of difficulty in affective prosody recognition encountered by individuals with autism spectrum condition varied across emotions. The findings of this systematic review highlighted the need for further research on affective prosody recognition in autism (e.g. studies that include tonal language speakers and autism spectrum condition individuals with lower cognitive or verbal abilities).

The advantages of anaerobic digestion (AD) technology in organic solid waste treatment for bioenergy recovery are evidenced in worldwide. Recently, more attention has been paid to on-site biogas research, as well as biogenic CO

The aim of this chapter is to provide a comprehensive review of the emerging technologies applied in food waste (FW) treatment from the aspect of cascade utilization, i.e., various high-value products derived from FW, fast volume reduction by biodrying, and energy recovery by comanagement of FW and domestic wastewater. Various value-added products can be selectively extracted from the FW matrix through combined biochemical, chemical, or thermal/physical approaches, including biomolecules (sugars, peptides, amino acids, etc.) and calcium-based and carbon-based absorbent materials. The biodrying process can be a promising alternative to treat humid FW at a large volume and high-quality refuse-derived fuel can be harvested. Anaerobic digestion processes often encounter difficulties such as frequent process failure and long retention time of the substrate, thus the feasibility of incorporating FW into domestic wastewater treatment plants via different scenarios is discussed.

Biochar addition in anaerobic digestion (AD) systems generally improves the transformation of organic waste and the production of methane, yet little is known on further recycling of the biogas residue into biochar for AD. Here we prepared biogas residue biochar by heating the residue of food waste after AD at 500°C. We comprehensively compared the performance of this biochar with coconut shell biochar and corn stalk biochar on anaerobic co-digestion of sewage sludge and food waste, and explored the corresponding mechanisms. Results show that the biogas residue biochar has the highest mean methane daily yield, of 432.16 mL per g of volatile solids, versus 377.66-386.30 mL for coconut and corn biochars. This finding is in agreement with the structure of biogas residue biochar, whose structure shows more abundant functional groups, especially basic functional groups, which can effectively neutralize fatty acids and alleviate systematic acidification. Results are also supported by characteristics of the biogas residue biochar, which enriched the abundance of electroactive Clostridia , Methanobacterium and Methan o brevibacter in sludge under thermophilic condition, thus shortening the process of methanation.

Anaerobic digestion has been recognized as an economical and effective way for food waste treatment and resource recovery. This chapter presented an overview on the researches about anaerobic digestion of food waste. Biochemical parameters and synergistic effect together with possible inhibition factors are analyzed to characterize the microbial catalyzed bioelectrochemical process. Phased anaerobic digestion (AD) and emerging AD-based bioelectrochemical systems including microbial fuel cell, microbial electrodialysis cell, and microbial electrosynthesis are introduced and evaluated. Resource recovery from AD of food waste in terms of CH4, H2, CH4, and H2 and volatile fatty acids are summarized. For the promotion of resource recovery, more attention should be paid to integrated technologies that can produce more useful products toward zero discharge. Furthermore a technological route for food waste conversion based on anaerobic digestion was proposed.

A new 'shape-orientated' continuous wavelet transform (CWT)-based algorithm employing an adapted Marr wavelet (AMW) with a shape matching index (SMI), defined as peak height normalized wavelet coefficient ( [Formula: see text] ) for feature filtering, was developed for chromatographic peak detection and quantification. Exploiting the chromatographic profile of a candidate peak, AMW-SMI algorithm emphasizes more on the matching of the overall chromatographic profile to a reference Gaussian shape, while partly alleviates the requirement on the signal intensity derived from single or several data points, thus it allows the detection of low-intensity features from metabolites at low abundance. AMW-SMI imposes maximum and minimum thresholds on the ridgeline width and length to define a valid ridgeline, which corresponds to a more stably shaped chromatographic profile. The maximum wavelet coefficient C

International audience; Efficient nutrient removal from mixed black water is under challenge in the context of global pollution control and circular economy. The anaerobic-anorexic-aerobic process is a widely used biological nutrient removal technology for wastewater treatment, yet its denitrification capacity is limited by the low biodegradable organics to nitrogen (C/N) ratio due to prior degradation of mixed black water. We have previously proved that weak electrical of 0.2 V could stimulate microbial denitrification of black water using an external electrical supply to ensure voltage stability. To reduce the dependence on additional electrical and to ensure a stable voltage output, we built a microbial fuel cell (MFC) and a microbial electrolytic cell (MEC) embedded in the anaerobic-two stage anoxic/aerobic (A-(A/O) 2) system in this study, where the MFC degrades organic matter and generates electricity first. Then, the electroactive bacteria in the MEC catalyze denitrification at low carbon levels, which is affected by microbial ultra-low weak electrical stimulation (MUlWES) generated by MFC. Results showed that the removal rates of total nitrogen (TN) and total phosphorus (TP) were up to 91.3% and 98.3% respectively at a stimulation voltage of 0.1 V. Fluorescence spectroscopy revealed the formation of aromatic proteins and an increase in tightly bound-extracellular polymeric substances (TB-EPS), suggesting the involvement of these compounds in electron transfer. Community analysis disclosed the activation of autotrophic denitrifying bacteria and the inhibition of most heterotrophic denitrifying bacteria.

The effects of pyrolysis temperature (350, 450, and 550 °C) on the properties of biochar prepared from chicken manure (CM), dairy manure (DM), and their digestates (CMD and DMD) were investigated in this study. The physicochemical properties and the transformation of phosphorous and heavy metal forms in various types of biochar were analyzed, and the bioavailability was assessed to optimize the pyrolysis condition towards biochar land application. The larger specific surface area was found in CM and CMD derived biochars (14.90–22.45 m2/g), as compared to DM and DMD derived biochars (1.17–7.36 m2/g). The highest contents of total phosphorous (TP) and bioavailable non-apatite inorganic phosphorus (NAIP) were obtained in DMD biochar, i.e., 49.31 and 27.03 mg/g TS, respectively. Cu and Zn are identified as the harmful heavy metal elements in manure derived biochars due to its high level of total concentration. When increasing pyrolysis temperature, the fractions of Zn and Cu in exchangeable-, carbonate-, and the organic-bonded state decreased and the fractions of manganese oxidized and residual state increased. Finally, the citric acid leaching treatment was proposed to decrease the Zn and Cu contents in biochar before land application. The overall leaching rates for Cu and Zn were 37–45% and 27–32%, respectively.

Most of the developing countries are in need of sanitary toilets due to insufficient supporting facilities and proven technology mainly on disposal of fecal sewage. A microbial fuel cell (MFC)-microbial electrolytic cell (MEC) coupling with an anaerobic baffle reactor (ABR) was used to realize simultaneous removal of nitrogen and carbon in fecal sewage and complete energy recycling. Configuration and rapid start-up of the ABR-MFC-MEC process treating fecal sewage was systematically studied. Results showed that the application of an external voltage of 0.5 V can shorten the start-up time and improve hydrogen production rate to 3.42 × 10−3 m3-H2/m3/d in the MEC unit, where the double-chamber MFC can drive MEC completing the synchronous coupling start-up. In the single and double chamber systems, bio-electrochemical processes both enhanced shock resistance capacity of the whole ABR-MFC-MEC process during coupled operation, with chemical oxygen demand (COD) removal rates of 99.2% and 98.9% for the single and double chamber systems respectively. Based on results of biological analysis, the coupled system has a distinct selective effect on microbial population and each unit has high microbial diversity to enhance the stability and resistance of the whole system for treatment of feces and urine., Graphical abstract Unlabelled Image, Highlights • A novel coupled bio-electrochemical process was developed to treat fecal sewage. • Optimal configuration and start-up mode of the coupled process were determined. • 0.5 V was determined as the threshold voltage shortening start-up time. • The coupling mechanism of the combined process were investigated.

Effects of biochar on co-digestion of pig manure and dewatered sewage sludge under different total solids (TS) were investigated. Biochar could accelerate the start-up of methanogenesis and shorten the adaptation phase. At TS5%, the methane daily production in biochar group was 60.6% higher than the control; nevertheless, when TS increased, the gap between two groups gradually narrowed. Additionally, the change on antibiotics resistance genes (ARGs) was also affected by TS and the biochar addition. Moreover, biochar was beneficial to reduce ARGs in liquid phase. At TS14%, the total ARGs abundance in the liquid phase of biochar group was 41.4% lower than the control, among which the reduction rates of etB(P), sul1, rpoB2, macA, mupA and mupB were more prominent. These findings could provide useful guidance for developing ARGs elimination strategy before their release into the environment.

It is crucial to have a review on the role of iron in water treatment for the guidance towards the selection of appropriate processes, content of iron, and application conditions, as there are few reviews available at present and the systematic information is lacking for both researchers and engineers. The objectives of this review are to summarize the state of arts with respect to iron applied in nitrogen removal, discuss chemical and biological or bio-chemical combined nitrogen removal pathways and processes coupled with iron, and to reveal reaction mechanisms as well as providing references or even solutions to pertinent the practical engineering application of nitrate removal coupling with iron. The following information have been summarized and discussed in details: (1) iron based materials with varieties of preparations and forms, (2) major coupling ways of nitrogen removal methods or processes with iron application, (3) chemical reaction equations about a variety of chemical and biological or bio-chemical combined processes and the main mechanisms. In addition, challenges and/or drawbacks during the nitrogen removal processes will also be discussed in this paper, which is aimed to seek better practical engineering applications of nitrate removal coupling with iron.

Delamination treatment is crucial in promoting the activity of bulk graphitic carbon nitride (g-C3N4). However, most of the currently used methods of exfoliating bulk g-C3N4 to achieve g-C3N4 thin layers suffer from low yield and environmental pollution. Herein, we developed a facile bacterial etching approach for the preparation of high-quality g-C3N4 nanosheets by exfoliating bulk g-C3N4 under room temperature. Morphology and physicochemical characterizations show that the bacteria-treated g-C3N4 (BT-CN) samples, especially BT-CN-2d, have a lamina-like two-dimensional (2D) in-plane porous structure, a significantly enlarged specific surface area (82.61 m2 g–1), and a remarkable narrow band gap (2.11 eV). X-ray photoelectron spectroscopy and electron paramagnetic resonance spectra confirm the dramatic enrichment of unpaired electron in the BT-CN-2d g-C3N4 nanosheets. EIS spectra and photocurrent tests indicate the fast electron transportation. As a result, the representative BT-CN-2d g-C3N4 photocatalyst...

This study assessed the digester stability and overall methane production of co-digestion of sewage sludge (SS) and pig manure (PM). Four different ratios of PM were mixed with SS to reach different final concentrations of total solids (TS), i.e. 4%, 6%, 8% and 10%. Volatile solids (VS) reduction rate decreased along with an increase in TS%, and the maximum cumulative methane yield of 342 mL/g VSrem was obtained in treatment with TS of 6%. When TS was ≥ 8%, accumulation of volatile fatty acids (VFAs), free ammonium nitrogen (FAN) and total ammonium nitrogen (TAN) were observed. At a TS content of 10%, VFAs accumulated to > 20000 mg/L and the highest FAN was 481 mg/L. The suppression of methanogenesis was negatively correlated with FAN and VFA/TIC (P

In this study, ozone-oxidation was used to treat synthetic chemical plating solution containing Cu(II)/Ni(II)-EDTA solution to realize the purpose of decomplexation. The effects of solution pH, initial concentration of Cu(II)/Ni(II)-EDTA, the molar ratio of EDTA to Cu(II)/Ni(II), and the coexistence of Cu(II)/Ni(II) on their removal efficiencies were investigated. The degradation of EDTA-Cu(II) and EDTA-Ni(II) were mainly attributed to OH oxidation, and the removal rates of Cu(II)/Ni(II) depend on the complete decomplexation. The removal rates of Cu(II) and Ni(II) was affected by the pH of solution, and the optimal pH was found to be 7–9; nevertheless, their removal rates can still be up to 90% even in acidic pHs of 3~5. When the molar ratio of EDTA to Cu(II)/Ni(II) increased from 1:1 to 3:1, the kinetics of metal ion removal rate declined from 0.0788 and 0.1139 min-1 to 0.0250 and 0.0271 min-1. The synergistic effect was found in the Cu(II)/Ni(II) blended system due to the higher catalytic capability and the lower complexation affinity toward EDTA for Ni(II). In summary, ozone oxidation can be considered as an effective technology to realize the complete decomplexation of Cu(II)/Ni(II)-EDTA that contained in chemical plating industry wastewater.

The aim of this paper is to select feasible agricultural straws as high-quality sustained-release carbon source and examine the effect of determined agricultural organic waste on improving denitrification efficiency. Five kinds of agricultural straws, i.e., the rice straw, the corn straw, the wheat straw, the broomcorn straw, and the reed straw, were evaluated in a self-designed drawer-type biological filter. Results showed that the contents of C, H, and N in the five straws were 34.0~41.0%, 4.9~5.4%, and 1.1~1.5% respectively. The highest TOC release capacity of the rice straw was 12.4 ± 1.3 mg g−1 and the average TOC release of other waste straws ranged from 6.0 to 9.2 mg g−1. The TN release capacities of all the five straws were at a low level, ranging from 0.2 to 1.4 mg g−1. Preliminary denitrification studies showed that the corn and the rice straw could be used as high-quality carbon sources, achieving a COD removal rate of 47.3~50.2% and a TN removal rate of 21.8~24.8% for wastewater with low C/N ratio. The rice straw and the corn straw founctioned both as favorable solid carbon sources and biofilm carriers; the carbon source quality of the corn straw lixivium is more beneficial to microbial utilization. The drawer-type biological filter has showed a good efficiency of denitrification for nitrogen removal when using agricultural straws as biofilm carriers.

With the fast-growing adoption of anaerobic digestion in food waste treatment, the appropriate disposal and utilization of digestate have become a prominent problem. Using digestate as a soil conditioner promotes the circular economy and the sustainable development of biogas production. Before the application of digestate, post treatment is necessary to reduce the volume and phytotoxicity, accelerate the stabilization, and conserve nutrients. In this paper, the properties of food waste digestate and the worldwide regulations on digestate for soil conditioning were summarized. The principles, mechanisms, and application prospects of the various post digestion treatment processes were reviewed and discussed, including dewatering, drying, and biological stabilization. Biodrying and hyperthermophilic composting (HTC) have great potential for accelerating digestate stabilization and reducing greenhouse gas emissions from digestate handling. Combined with chemical or biological approaches, biodrying and HTC processes could achieve a 27%–84% nitrogen fixation. Thus, biodrying and HTC are applicable in the post digestion stabilization of food waste digestate. Nonetheless, more attention could be paid to assure product quality via source collection management and process optimization.

In this study, the performance of a circular microbial electrolysis cell (MEC) system on removing NO3−-N/NO2−-N and NH4+-N at low C/N ratios was investigated. With the assistance of active bioelectrode, electron transportation and utilization efficiency between electron donor and acceptor was enhanced in MEC. High rate of nitrogen removal was observed in MEC at 0.2 V, which was 695.6 and 514.5 g-N/m3/d, respectively under COD/N = 2 and COD/N = 1. Without carbon source addition, the symbiotic activity of Anammox and electrochemical autotrophic denitrifiers were verified in MEC, in which the demand of NO2−-N for NH4+-N removal is calculated to be ∼1.3. Microbial community analysis revealed that the biocathode was enriched with autotrophic and heterotrophic nitrate/nitrite-reducing bacteria (e.g. 5.09 % Candidatus, 4.35 % Thauera and 3.34 % Comamonas), as well as the fermentative bacteria (e.g. 7.57 % Bacteroidetes). As heterotrophic denitrification, electroactive autotrophic denitrification, partial-denitrification and Anammox can coexist and collaborate in the MEC system, the strict nitritation to produce only nitrite toward Anammox can be avoided.

Epithelial-mesenchymal transition (EMT) contributes to the invasion and metastasis of numerous malignant cancers, including melanoma. A significant higher expression of B-lymphoma Moloney murine leukemia virus insertion region-1 (Bmi-1) has been reported in cell lines from metastatic melanoma compared to cell lines from primary melanoma. There are studies that show that knockdown of Bmi-1 could induce E-cadherin expression in melanoma cells. However, the role of Bmi-1 in mediating EMT-like changes in melanoma has not yet been fully studied. In the present study, knockdown of Bmi-1 by shRNA transduction decreased the invasion properties of the cultured human melanoma cells A375 by a Matrigel invasion assay, along with alterations in EMT-related markers E-cadherin, α-catenin, vimentin and N-cadherin. The aforementioned altered expression of EMT markers was verified in BALB/c-nude mouse xenografts. Furthermore, to explore the underlying regulatory mechanism of EMT, we detected the significant downregulation of p-Akt/p‑NF-κB/MMP-2 and the upregulation of PTEN in Bmi-1-silenced A375 cells. The present study demonstrated that knockdown of Bmi-1 significantly inhibited the aggressive behavior of melanoma by reversing EMT-like changes via the PTEN/p-Akt/p‑NF-κB/MMP-2 pathway.

Four kinds of biochar were obtained by pyrolysis carbonization and hydrothermal carbonization from swine manure digestate, i.e. pyrochar (HC, HC-Fe) and hydrochar (HTC, HTC-Fe). Batch fermentation was conducted to compare their effects on the co-digestion of sewage sludge and swine manure. Both pyrochar and hydrochar present positive effect on methane production, nevertheless the higher methane yields were obtained in HTC and HTC-Fe digesters. No advantage was observed for the iron impregnation. The maximum methane yield was 308.4 mL/g VS in HTC digester, which was 27% and 49% higher than HC and Control, respectively. The surface functional groups of hydrochar are more abundant than pyrochar, which is favorable for promoting the syntrophic anaerobic metabolism, as revealed by the promoted substrate hydrolysis and VFAs consumption rate. Thus, it is proposed to convert swine manure digestate to hydrochar, which can be recirculated back to the AD reactor to increase the digestion efficiency.

To provide insight into direct interspecies electron transfer (DIET) via carbon-based materials and ferric oxides, the effects of three conductive materials (i.e. activated carbon (AC), iron modified activated carbon (FEAC) and goethite (FEOOH)), on methanogenesis from volatile fatty acids (VFAs) were evaluated. Under the acid stress (~4 g/L VFAs), the maximum methane yield of 266 mL/g-chemical oxygen demand (COD) was found in the FEOOH supplemented reactor, which was 48% higher than that of AC reactor. The reasons for the enhanced activity of the electron transport chain and extracellular electron transfer ability by FEOOH include: 1) the activation on iron-containing enzymes that involved in methanogenesis and acidogenesis; 2) selective enrichment on functional microorganism. The higher electron donating capacities (EDC) value of FEOOH may be a triggering factor on the growth of Syntrophomonadaceae, which perform DIET with methanogens (Methanosaeta and Methanosarcina) for the syntrophic degradation of VFAs.