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In this work, we systematically investigated the performance and degradation mechanism of quinoline using a persulfate (PS) or sulfite (S(Ⅳ)) assisted WO 3 /CuFe 2 O 4 /Cu (10WCC) photocatalysis. The experimental results showed the degradation efficiency of quinoline were the best in the PS-photocatalysis system with the catalyst dosage of 3 g/L, the PS dosage of 4 mmol/L and pH of 7, and that were the best in the S(Ⅳ)-photocatalysis system with the catalyst dosage of 2 g/L, the S(Ⅳ) dosage of 5 mmol/L and pH of 7. In addition, the S(Ⅳ)-photocatalysis system (77.2%, 1.43 h−1) had lower degradation efficiency than the PS-photocatalysis system (100%, 11.04 h−1) under visible light irradiation. The main active species in the 10WCC/VIS/PS system were h+ and ·OH, while in the 10WCC/VIS/S(Ⅳ) system they were h+, ·O 2 - and SO 4 ·-. This was likely because the electrons of 10WCC could not be captured by S(Ⅳ), and more electrons were captured by O 2 to form ·O 2 -. Some h+ oxidized S(Ⅳ), resulting in a small amount of ·OH. Thus, ·O 2 - and SO 4 ·- played key roles in presence of S(Ⅳ). Moreover, h+ was most important in both systems, indicating photocatalytic degradation dominated quinoline removal reaction. This study provides some reference for SO 4 ·- coordinated photocatalysis technology. [Display omitted] • WO 3 /CuFe 2 O 4 /Cu Z-scheme catalyst was constructed. • Quinoline was removed by persulfate or sulfite assisted photocatalytic process. • The main active species were different between persulfate system and sulfite system. • Degradation mechanism and pathways of quinoline in two systems were compared. [ABSTRACT FROM AUTHOR]

Sulfaquinoxaline (SQX) is a vital sulfonamide antibiotic for the treatment of livestock infections. Although its degradation has become a research focus in the last few years, its biodegradation process and biometabolic mechanisms were rarely studied. In this research, microbial electrolytic cells (MECs) were used to remove SQX using sodium acetate as a co-substrate. The findings indicated that the maximum removal rate of SQX for a 5-day period in co-substrate reached 94.2%, and SQX exhibited a lower resistance (45.64 Ω) and had a larger double-layer area than a single substrate (95.03 Ω). LC MS/MS analysis suggested that SQX could eventually degrade to 17 byproducts through hydrolysis, hydroxylation, N rearrangement and sulfur reduction. Density flooding theory (DFT) calculations showed that sodium acetate addition weakened the N-C bond and facilitated hydroxylation. Meanwhile, the fluorescence composition of fDOM shifted from protein-like to humic acid-like with co-substrate supplementation. Microbial community analysis showed that Actinobacteria, Proteobacteria, Bacteroidota and Chloroflexi were highly correlated with SQX removal. Analysis of the metabolic pathways showed that key enzymes such as NAT, CAT, DHP and NAD+ were involved in the degradation of SQX. Biotoxicity tests indicated that weak electrical stimulation was beneficial in reducing biotoxicity. These results provide theoretical basis and new insights into the bioelectrochemical degradation of SQX. [Display omitted] • The feasibility of facilitating SQX degradation through MEC was first assessed. • The degradation of SQX was effectively improved with sodium acetate addition. • The main metabolic pathway of SQX was hydroxylation by DFT calculations. • The correlation between SQX degrading bacteria and exoelectrogens was existed. • The NAT and CAT had higher abundance based on the number of genes for key enzymes. [ABSTRACT FROM AUTHOR]

In this study, the attempt was made to enhance the degradation of the typical antibiotics, metronidazole (MNZ) by coupling three-electrode photocatalytic and microbial fuel cell systems (PMFC). The PMFC reactor was constructed, and the photocatalytic bioanode, attached with TiO 2 , was synthesized and characterized using SEM, EDS, XPS methods. The stability of microbial on bioanode was tested during acclimatization process. Electrochemical characteristics, including power density, CV and EIS curve, were analyzed to explore the advantage of power generation and higher electron transfer interaction in the PMFC. Compared with the traditional MFC system, the improved degradation and enhanced mineralization of MNZ were achieved, and the 1.30 and 1.24-fold increase in MNZ and TOC removal were realized, respectively. The three degradation pathways of MNZ were identified by LC-MS in the coupling PMFC, and the intermediates were more easily to further degrade and mineralize. The structure of the microbial community was demonstrated, and the functional species consisted of MNZ degradation bacteria, exoelectrogens, hydrocarbon removal bacterial, and nitrogen removal bacterial, were largely enriched in the PMFC, contributing to the improved electricity production, MNZ degradation and photoelectric effect. Moreover, the photoelectric played the selective role in the enrichment of functional microbial. The study provides a promising and environmentally approach for the treatment of containing antibiotics wastewater in the practical application. [Display omitted] • The PMFC system was developed for the treatment of metronidazole. • The performance of metronidazole degradation and mineralization was strengthened in the PMFC system. • The higher electron transfer reaction was obtained in the PMFC. • Degradation bacterial, exoelectrogens, nitrogen removal bacterial were enriched and coexisted. [ABSTRACT FROM AUTHOR]

Anaerobic fermentation (AF) could achieve simultaneous recovery of short-chain fatty acids (SCFAs) and phosphorus (P) when waste activated sludge (WAS) and meat processing waste (MPW) act as co-substrate. However, long-chain fatty acids, the degradation intermediates of lipids, always inhibit anaerobic microbial activity. Therefore, sodium hydroxide (NaOH) conditioning was applied to improve the lipid-rich AF performance in this study. The results demonstrated that 96% WAS (v/v) with NaOH addition that remaining at pH 7.5 could achieve the maximum SCFAs yield (1180.05 mg/g VS fed) at 12 d, and ortho-P content in the AF liquor (AFL) was much more than that of without NaOH addition. Anaerovibrio and Aminobacterium , one kind of lipolytic and proteolytic bacteria, respectively, became the major genus in the lipid-rich AF system. 86% of P in the AFL from 96% WAS + pH 7.5 reactor was recovered through vivianite crystallization method, with 91% of SCFAs remaining in the post-AFL. Meanwhile, analysis results verified vivianite formation in the P precipitate products. Overall, this study provided a new idea to achieve SCFAs and P simultaneous recovery from WAS and MPW through AF with NaOH conditioning and vivianite crystallization. [Display omitted] • Meat processing waste and activated sludge were treated by anaerobic fermentation. • NaOH conditioning enhanced SCFAs yield and P release from lipid-rich AF. • Maximal SCFAs yield (1180.05 mg/g VS fed) occurred at pH 7.5 with NaOH addition. • Anaerovibrio , one kind of lipolytic bacteria, was stimulated during lipid-rich AF. • Ortho-P release from the fermentation system was favorable for vivianite recovery. [ABSTRACT FROM AUTHOR]

The calcined Mg–Fe layered double hydroxides (Mg–Fe–CLDHs) with the Mg–Fe molar ratio of 3 were used as adsorbents to remove sulfate in natural water. The Mg–Fe–CLDHs were synthesized by the co-precipitation method. The influences of initial adsorbent concentration, temperature, and pH on the adsorption of sulfate on Mg–Fe–CLDHs were evaluated. Three kinetic models and two isotherms were used to fit the experimental data, and it was found that the pseudo-second order kinetics model and Langmuir isotherm model could be used to describe the uptake process appropriately. Characteristics of the adsorbents and adsorption mechanism were analyzed by XRD, FT-IR, BET, TG-DSC, and SEM. [ABSTRACT FROM PUBLISHER]

• Bio-foaming seemed to be caused by the accumulation of volatile fatty acids. • CH 4 yield was increased by 2.5–11.3% after Fe0 dosing at a loading rate of 7.5 kgVS/m3/d. • Addition of Fe0 decreased the degree of effluent surface active by 49.7–59.2%. • Fe0 dosing was assessed by comparison with commercial antifoam agents. Bio-foaming during the anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW) is a major cause of unstable reactor operations, especially under high organic loading rates (OLRs). Here, we used two 40-liter anaerobic reactors to deal with the actual organic fraction of municipal solid waste at OLRs of 5 and 7.5 kgVS/m3/d and tried to inhibit bio-foam generation by dosing with Fe0. One of reactors had 400 g of Fe0 added before operation and additional 200 g of Fe0 was added when the operating conditions changed; the other one was the control reactor with no Fe0 dosing. The results show that bio-foam was generated in the control reactor at an organic shock loading of 10 kgVS/m3/d and re-startup at 5 kgVS/m3/d, while the reactor containing Fe0 operated normally. Due to the surfactant attributes of volatile fatty acids (VFAs), the probability of bio-foam generation was positively correlated with the effluent's degree of surface activity (SA) induced by VFAs, which is a parameter representing the foaming potential. Because VFA biodegradation was enhanced in the reactor with added Fe0, at the position of Fe0 accumulation, the SA was decreased by 49.7–59.2%. Furthermore, the effect of Fe0 dosing on inhibiting bio-foam was evaluated by comparison with traditional commercial anti-foam agents. The results suggest possible reasons for bio-foam generation in OFMSW AD and suggest the reasonable usage of Fe0 to inhibit bio-foam formation. [ABSTRACT FROM AUTHOR]

• Zn(II) inhibited the performance of SDM and multiple antibiotic biodegradation. • Zn(II) intervention promoted protein release in the DOM of EPS. • ZnuA and zipB can provide abundant sites to bind Zn(II) and antibiotics. • The effect of Zn(II) stress on ARGs was higher than that of antibiotics. • The abundances of MGEs, Zn-RGs, and ARGs were positively correlated. High-strength nitrogen and antibiotics-containing wastewater can be efficiently eliminated by simultaneous denitrification and methanogenesis (SDM). Heavy metals and antibiotics are two critical factors that can lead to horizontal transfer of antibiotic resistance genes (ARGs), which can be simultaneously detected in wastewater. Unfortunately, the impacts of heavy metals on SDM and antibiotic biodegradation have not been fully elucidated. Herein, the effects of SDM and multiple antibiotics biodegradation, extracellular polymeric substances (EPSs) and protein response mechanisms, and ARG fate under Zn(II) stress were comprehensively evaluated. The results indicated that a high level of Zn(II) (≥5 mg/L) stress significantly decreased the degradation rate of multiple antibiotics and suppressed denitrification and methanogenesis. In addition, Zn(II) exposure prompted the liberation of proteins from microbes into the EPSs, and the combination of EPSs with small molecules quenched the original fluorescent components and destroyed the protein structure. The dominant proteins can bind to both Zn(II) and multiple antibiotics through several types of chemical interactions, including metallic and hydrogen bonds, hydrophobic interactions, and salt bridges, relieving the toxicity of harmful substances. Moreover, metagenomic sequencing revealed that the abundance of zinc resistance genes (Zn-RGs), ARGs (mainly tetracyclines), and mobile genetic elements (MGEs) increased under Zn(II) stress. Mantel test illustrated that the ARGs mecD, tetT, and tetB(60) were most affected by MGEs. Moreover, molecular network analysis revealed that several MGEs can bridge metal resistance genes (MRGs) and ARGs, facilitating the horizontal transfer of ARGs. This study provides theoretical guidance for the environmental risk control of antibiotics-containing wastewater treated by an SDM system. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Pyrolytic carbon from waste tire pyrolysis was used to boost the AD performance. • Pyrolysis temperature for pyrolytic carbon used in AD should be higher than 800 °C. • The conductivity of pyrolytic carbon at 1000 °C is (12.5–25.2) × 104 S/m. • The hydrolysis of vinegar residue is enhanced and the VFA content is 3330 mg/L. • The maximal CH 4 yield is 454.53 mL CH 4 /gVS, representing an increase of 104.4%. Random disposal of waste tires and vinegar residues is deleterious to the environment; these materials can be sufficiently treated using pyrolysis and anaerobic digestion, respectively. In this study, pyrolytic carbon was used to enhance the performance of the anaerobic digestion of vinegar residues, which is a much more economic method comparing with dosing commercial-level carbon based materials. The conductivity of pyrolytic carbon at 1000 °C is much higher than that of commercial activated carbon. At a dosage of 10 g per 29 g of vinegar residues, the maximum volatile fatty acid production was 4225.4 mg COD/L in the reactor (effective volume of 400 mL) with inoculum to substrate ratio (ISR) of 1:1, representing an increase of 50.3% from that of the control reactor. A sufficient dosage is necessary to improve methane yield. The maximum methane yield was obtained at a pyrolytic carbon dosage, obtained at 1000 °C, of 12 g per 29 g of vinegar residues. The results indicated that the differences in the microbial communities of the control and experimental reactors correlated with the performance; however, the deep microbial mechanism of pyrolytic carbon boosting anaerobic digestion performance must be explored in further studies. [ABSTRACT FROM AUTHOR]

Exploration of value-added products from wastewater treatment plants (WWTPs) was promising for its sustainable development. This study simultaneously addressed the possibility of volatile fatty acids (VFAs) production boost and cellulosic components recovery from fine-sieving fractions (FSF) under initial alkaline conditions. The step utilization of FSF was relatively untapped in similar literatures. The effect of different initial pH values with 8.5, 9.5 and 10.5 (defined as F-8.5, F-9.5 and F-10.5) on fermentation performance were investigated. Then, the fermentation residues were collected to evaluate the changes in chemical structure and thermodynamic properties by fourier transform infrared spectroscopy (FTIR) and thermo-gravimetric (TG) analysis. Furthermore, analysis of the changes in microbial community structure and the interaction between functional genus and performance parameters were undertaken by high throughput sequencing and canonical correspondence analysis (CCA). Results showed that F-10.5 obtained the highest VFAs yields of 234 mg/g VSS, due to efficient polysaccharides release and inhibited methane production. However, high alkaline intensity caused proteins denaturation. Acidogenesis kinetics suggested that the fermentation rate was chemical-dominated. Although crystalline structure was more disordered with increasing alkalinity, the weight loss was lower than 2.5%, making it possible to recover cellulose from fermented residues. Interaction between functional genus and performance parameters revealed the microbial mechanism during the alkaline fermentation. Consequently, the initial-alkaline motivated fermentation was proved to be a promising technology in value-added products recovery to be cost economic, energy positive and environmental friendly. [Display omitted] • VFAs production was accelerated due to efficient chemical-dominated hydrolysis. • Change in cellulose structure was detected with less weight loss after fermentation. • Alkaline fermentation significantly affected the microbial community structure. • The process was evaluated to be cost effective, energy and environmental positive. [ABSTRACT FROM AUTHOR]

High value-added utilization of industrial waste is important for environmental protection and sustainability. The objective of this study was to recycle industrial wastes, silica fume (SF) and aluminium ash (AA) as raw materials to substitute chemicals for sustainable and low-cost SUZ-4 zeolite (L-SUZ-4) synthesis in one pot. The synthesis parameters to obtain pure L-SUZ-4 were optimized as x KOH(x = 7.84–9.33): y Al 2 O 3 (y = 0.81–1.10):2.6TEAOH:21.2SiO 2 : z H 2 O(z = 330.72–712.32) at 150 °C for 96 h. The notably high yield of L-SUZ-4 (up to 85%) indicated that silicon and aluminium species in SF and AA are not only easy to be activated but also liable to be incorporated into the zeolitic framework. Exploration of L-SUZ-4 synthesis process by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) characterizations indicated that the synthesis follows the liquid phase transition mechanism. It can also be observed that the complete dissolution of SF is the rate-determing step during the induction period. Meanwhile, the adsorption ability of L-SUZ-4 for Cd2+ in water was first investigated. A notably maximized adsorption amount (q max = 263.68 mg/g) of L-SUZ-4 for Cd2+ was obtained, which is higher than the other adsorbents investigated in this work or those described in the literature. The sustainable production and outstanding adsorption performance of L-SUZ-4 make it a very promising adsorbent for heavy metal removal with practical application prospects, which is the typical case of "waste to treat waste". [Display omitted] • SUZ-4 zeolite is first prepared using silica fume and aluminum ash by one-pot. • The formation mechanism of the low-cost SUZ-4 zeolite is expatiated. • The low-cost SUZ-4 zeolite displays high adsorption capacity for Cd2+. • The low-cost SUZ-4 is a very promising adsorbent from the practical application. [ABSTRACT FROM AUTHOR]

• 150 mgN/L of nitrate photolysis improved SCFAs production from WAS. • Nitrate increase (150∼375 mgN/L) has no significant promotion on SCFAs in photolysis. • ROS contributed more than RNS on WAS solubilization, hydrolysis and acidification. • Both AFB and NRB enriched for the high SCFAs production and complete denitrification. • Genes related to glycolysis, amino acid, acetate and nitrogen metabolism were enhanced. Nitrate photolysis has become an efficient, low-cost and promising technology for emerging contaminants removal, while its performance and mechanism for waste activated sludge (WAS) treatment is still unknown. This study innovatively introduced nitrate photolysis for WAS disintegration, and investigated the effect of nitrate addition (150–375 mg N/L) for short-chain fatty acids (SCFAs) production during anaerobic fermentation (AF). The results showed that nitrate photolysis significantly promoted the SCFAs production from WAS, and peaked at 280.7 mg/g VSS with 7-d fermentation with 150 mg N/L addition (150N-UV), which increased by 8.8–35.0 % and 10.7–23.3 % compared with other photolysis groups and sole nitrate groups. Effective release of the soluble organics was observed in the nitrate photolysis groups during AF, especially soluble proteins, reaching 1505.4 mg COD/L at 9 d in 150N-UV group, promoted by 7.0∼15.7 % than nitrate/nitrate photolysis groups. The model compounds simulation experiment further demonstrated the positive effect of nitrate photolysis on organics hydrolysis and SCFAs accumulation. The result of the radical capture and quenching verified the reactive oxygen species contributed more compared with reactive nitrogen species. Functional group analysis confirmed the effective bioconversion of the macromolecular organics during the fermentation. Moreover, the nitrate photolysis enhanced the enrichment of the functional consortia, including anaerobic fermentation bacteria (AFB), e.g., Fnoticella, Romboutsia, Gracilibacter and Sedimentibacter , and nitrate reducing bacteria (NRB), e.g., Acinerobacter and Ahniella. The macrogenetic analysis further revealed that glycolysis, amino acid metabolism, acetate metabolism and nitrogen metabolism were the dominating metabolic pathways during fermentation, and the abundance of the relevant genes were enhanced in 150N-UV group. [Display omitted] [ABSTRACT FROM AUTHOR]

• A novel upflow microaerobic sludge reactor was constructed. • The removal efficiencies of NH 4 +-N and TN reached 90.53% and 80.77%, respectively. • AOB, NOB, anammox, autotrophic and heterotrophic denitrifiers cooperated in UMSR. • Partial denitrification/anammox was dominant nitrogen conversion pathway. • The small height waterfall was applicable to treat low strength NH 4 +-N wastewater. A novel falling water aeration-external reflux upflow microaerobic sludge reactor (UMSR) was designed to treat wastewater with the low chemical oxygen demand (COD) to total nitrogen (TN) ratio. The result showed the concentration of dissolved oxygen (DO) in the reactor could be accurately controlled by adjusting the reflux ratio of oxygenated water. The higher aeration efficiency in pollutant removal could be obtained by the reoxygenation mode of the small height falling water. At the reflux ratio of 5:1, the ammonium, nitrite and nitrate nitrogen concentrations in the effluent of UMSR were 6.0, 0.4 and 6.1 mg/L on average, respectively. The removal efficiency of ammonium nitrogen and total nitrogen reached 90.53% and 80.77%, respectively with the influent COD/TN as being 1.0. The structure of the microbial community confirmed the existence of partial-denitrification/anaerobic ammonium oxidation (anammox) bacteria, autotrophic and heterotrophic denitrifiers contributed to nitrogen and carbon removal in UMSR. [ABSTRACT FROM AUTHOR]

Waste activated sludge (WAS) is a promising phosphorus (P) source for fertilizer production; however, it is mainly enmeshed inside microbial cells or extracellular polymeric matrixes. Thus, efficient P release is a key goal. This study provided an effective route to simultaneously release organic P (OP) and harvest hydrogen from WAS via bio-electrolysis assisted with prefermentation system (AD_MEC). The clarification of P fractions in both solid and liquid phases and the underlying mechanism in this cascading system were explored. Free nitrous acid (FNA) was employed to enhance WAS hydrolysis. The results showed that hydrogen generation was effectively accelerated: 0.54 mL per gram sludge (in volatile suspended solids (VSS)) was produced from raw WAS (AD_MEC_RWAS), which increased to 1.27 mL/g VSS from FNA-pretreated WAS (AD_MEC_FWAS). The limited OP release by prefermentation was enhanced via MECs; additionally, it was further promoted by FNA, and the treatment time was also shortened. The maximum OP release efficiency reached 54.6% at 112 h (AD_MEC_FWAS). Additionally, non-apatite and inorganic apatite P may regenerate in MECs due to the localized decrease in pH caused by hydrogen generation. This work may provide a scientific basis to enhance P and hydrogen co-recovery from WAS in forthcoming implementation. Image 1 • H 2 recovery and P release from WAS was achieved in cascading conversion system. • The limited OP release in prefermentation was accelerated via bio-electrolysis. • FNA played a positive effect on H 2 recovery and OP release from WAS. • Underlying mechanism of cascading conversion system for P release was explored. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A novel up-flow microaerobic granular sludge reactor was constructed. • NH 4 +-N and TN removal averaged 92.35% and 90.41%, respectively, at a low C/N ratio. • Nitrifiers, denitrifiers, and anammox bacteria thrived in the microaerobic system. • An ecological nitrogen conversion model of granule sludge was proposed. Abstract In this study, a novel upflow microaerobic sludge reactor (UMSR) was constructed to conduct anaerobic digestion of municipal wastewater with low carbon and nitrogen ratio (C/N). Oxygen in the UMSR was supplied by falling water and external recirculation. Excellent nitrogen removal performance was obtained in the UMSR for treating wastewater with low C/N ratio at a temperature of 25 °C and a hydraulic retention time of 24 h. Ammonium and total nitrogen removal efficiencies averaged 92.35% and 90.41%, respectively, and sludge granulation occurred during acclimation. The inferred metabolism of nitrogen removal and ecological positions of functional microbe were integrated into a granule model by scanning electron microscopy. Additionally, the analysis of microbial community indicated that aerobic nitrifying bacteria and heterotrophic bacteria survived on the surface of sludge floc and granules while the anaerobic autotrophic, heterotrophic denitrifying, and anaerobic ammonia oxidation bacteria were present in the inner layer. [ABSTRACT FROM AUTHOR]

Current studies have employed various chemicals for disintegrating and hydrolyzing microbial cells in waste activated sludge (WAS). However, a comprehensive process assessment over the whole anaerobic digestion process has seldom been proposed. Besides, the characterization of microbial community responses to these chemicals is not well understood. In this study, the effects of five typical chemicals: solubilizer (β-cyclodextrin, CD), alkaline (NaOH), peroxide (peracetic-acid, PA), biological (rhamnolipid, RL) and chemical (sodium dodecylsulphate, SDS) surfactants on WAS digestion were examined. Higher efficiencies of WAS solubilization, hydrolysis and acidification were achieved by CD treatment, followed by RL and SDS. Methanogenesis was also strongly chemicals-dependent. Shifts in microbial community structure were observed in all chemical-pretreated WAS. The community in RL, CD and PA was dominated by microorganisms that anaerobically hydrolyze organics to acids, while that in NaOH and SDS was mainly associated to biogas production. This study proved that the overall performance of WAS digestion was substantially depended on the initial chemical pretreatments, which in turn influenced and was related to the microbial community structures. Although the economic advantage might not be clear yet, the findings obtained in this work may provide a scientific basis for the potential implementation of chemicals for WAS treatment. [ABSTRACT FROM AUTHOR]