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[Display omitted] • Conventional H–B process with process optimization and CCSU technology is a near-term option. • Sustainable N-fertilizer that relies on air and water could revolutionize the agriculture business. • Data from demonstration plants would accelerate scale-up and market trend analysis. • Cost of electrolysis-driven HB ammonia is competitive with traditional technology in some regions. • Simultaneously achieving DOE target ammonia yield and energy efficiency remains elusive. [ABSTRACT FROM AUTHOR]

Heterotrophic-sulfur autotrophic denitrification (HAD) has been proposed to be a prospective nitrogen removal process. In this work, the potential of fermentation liquid (FL) from waste-activated sludge (WAS) as the electron donor for denitrification in the HAD system was explored and compared with other conventional carbon sources. Results showed that when FL was used as a carbon source, over 99% of NO 3 −-N was removed and its removal rate exceeded 14.00 mg N/g MLSS/h, which was significantly higher than that of methanol and propionic acid. The produced sulfate was below the limit value and the emission of N 2 O was low (1.38% of the NO 3 −-N). Microbial community analysis showed that autotrophic denitrifiers were predominated in the HAD system, in which Thiobacillus (16.4%) was the dominant genus. The economic analysis showed the cost of the FL was 0.062 €/m3, which was 30% lower than that in the group dosed with methanol. Our results demonstrated the FL was a promising carbon source for the HAD system, which could reduce carbon emission and cost, and offer a creative approach for waste-activated sludge resource reuse. [Display omitted] • Waste activated sludge FL could be an alternative carbon source for HAD systems. • FL achieved higher NO 3 −-N removal rate compared to methanol and propionic acid. • Low N 2 O emissions were achieved in the HAD systems used FL as carbon source. • The cost of the FL as carbon source was 30% lower than that of methanol. [ABSTRACT FROM AUTHOR]

Anaerobic digestion (AD) is a promising technique for waste management, which can achieve sludge stabilization and energy recovery. This study successfully prepared Fe 3 O 4 @ceramsite from WAS and applied it as an additive in sludge digestion, aiming to improve the conversion of organics to biomethane efficiency. Results showed that after adding the Fe 3 O 4 @ceramsite, the methane production was enhanced by 34.7% compared with the control group (88.0 ± 0.1 mL/g VS). Further mechanisms investigation revealed that Fe 3 O 4 @ceramsite enhanced digesta stability by strong buffering capacity, improved sludge conductivity, and promoted Fe (III) reduction. Moreover, Fe 3 O 4 @ceramsite has a larger surface area and better porous structure, which also facilitated AD performance. Microbial community analysis showed that some functional anaerobes related to AD such as Spirochaeta and Smithella were enriched with Fe 3 O 4 @ceramsite treatment. Potential syntrophic metabolisms between syntrophic bacteria (Syntrophomonas , associated with DIET) and methanogens were also detected in the Fe 3 O 4 @ceramsite treatment AD system. • Fe 3 O 4 @ceramsite promoted methane production from WAS digestion. • Fe 3 O 4 @ceramsite enhanced digesta stability and sludge organics dissolution. • Larger surface area and better pore structure of Fe 3 O 4 @ceramsite facilitated AD performance. • Some functional anaerobes related to AD were enriched. [ABSTRACT FROM AUTHOR]

Methane recovery from waste activated sludge (WAS) through anaerobic digestion is generally restricted by the poor degradability of WAS. Herein, a novel sludge pretreatment technology by using the calcium hypochlorite (Ca(ClO) 2) in enhancing the methane production from WAS anaerobic digestion was reported. The solubilization of WAS was significantly increased after 10–240 mg Ca(ClO) 2 /g VS (VS: volatile solids) pretreatment for 48 h, under which the solubilization was 1.7–3.4 folds (i.e., 0.17–0.34 mg SCOD/mg VS; SCOD: soluble chemical oxygen demand) higher than that without Ca(ClO) 2 pretreatment (i.e., 0.1 mg SCOD/mg VS). Correspondingly, the methane production was increased from 250.0 ± 5.3 mL/g VS to 385.1 ± 3.3 mL/g VS with the doses of Ca(ClO) 2 increasing from 10 mg/g VS to 240 mg/g VS, resulted in an increasing methane production of 3.6%–59.7% than that without Ca(ClO) 2 pretreatment. The microbial community composition results exhibited that the populations of key acidogens (e.g., Longilinea sp.) and methanogens (e.g., Methanosaeta sp.) were both reduced significantly. Moreover, Ca(ClO) 2 decreased the cells viability, leading to a 76.2% reduction of living cells fraction. Accordingly, it was further confirmed that high dosage of Ca(ClO) 2 could inhibit three microbial-related processes relevant to methane production, i.e., acidification, hydrolysis and methanogenesis. [Display omitted] • Ca(ClO) 2 pretreatment enhanced methane production from WAS digestion. • Methane yield is positively related to pretreatment level of Ca(ClO) 2. • High dosage of Ca(ClO) 2 decreased the abundance of acidogens and methanogens. • High dosage of Ca(ClO) 2 inhibited hydrolysis, acidification, and methanogenesis. [ABSTRACT FROM AUTHOR]

Wastes recycling and reutilization technique could simultaneously fulfill waste control and energy recovery sustainably, which has attracted increasing attention. This work proposed a novel waste reuse technology utilizing ceramsite and amended Fe 2 O 3 -ceramsite made from waste activated sludge (WAS) as additives to promote the yield of methane from WAS anaerobic digestion (AD). Experimental results demonstrated that compared to the control (85.05 ± 0.2 mL CH 4 /g-VS), the cumulative methane yield was effectively enhanced by 14% and 40% when ceramsite and Fe 2 O 3 -ceramsite were added. Further investigation revealed that ceramsite, especially the Fe 2 O 3 -ceramsite, enriched the populations of key anaerobes involved in hydrolysis, acidification, and methanogenesis. Meanwhile, potential syntrophic metabolisms between syntrophic bacteria and methanogens were confirmed in the Fe 2 O 3 -ceramsite AD system. Mechanisms studies exhibited that ceramsite and Fe 2 O 3 -ceramsite reinforced intermediate processes for methane production. The favorable pore structure, enhanced Fe (III) reduction capacity and conductivity also contributed a lot to the AD process. [Display omitted] • Amended Fe 2 O 3 -ceramsite was more favorable to enhance WAS anaerobic digestion. • Ceramsite enriched functional microbes and constructed potential syntrophic metabolisms. • Intermediate processes for methane production were all enhanced by ceramsite. • Better pore structure and enhanced conductivity facilitated the methane production. [ABSTRACT FROM AUTHOR]

The practice of aquaculture is associated with the generation of a substantial quantity of effluent. Microalgae must effectively assimilate nitrogen and phosphorus from their surrounding environment for growth. This study modeled the algal biomass film, NO 3 –N concentration, and pH in the membrane bioreactor using the response surface methodology (RSM) and an artificial neural network (ANN). Furthermore, it was suggested that the optimal condition for each parameter be determined. The results of ANN modeling showed that ANN with a structure of 5-3 and employing the transfer functions tansig-logsig demonstrated the highest level of accuracy. This was evidenced by the obtained values of coefficient (R2) = 0.998, R = 0.999, mean squared error (MAE) = 0.0856, and mean square error (MSE) = 0.143. The ANN model, characterized by a 5-5 structure and employing the tansig-logsig transfer function, demonstrates superior accuracy when predicting the concentration of NO 3 –N and pH. This is evidenced by the high values of R2 (0.996), R (0.998), MAE (0.00162), and MSE (0.0262). The RSM was afterward employed to maximize the performance of algal film biomass, pH levels, and NO 3 –N concentrations. The optimal conditions for the algal biomass film were a concentration of 2.884 mg/L and a duration of 6.589 days. Similarly, the most favorable conditions for the NO 3 –N concentration and pH were 2.984 mg/L and 6.787 days, respectively. Therefore, this research uses non-dominated sorting genetic algorithm II (NSGA II) to find the optimal NO3–N concentration, algal biomass film, and pH for product or process quality. The region has the greatest alkaline pH and lowest NO 3 –N content. • Algal biomass film, NO 3 –N concentration, and pH were predicted using RSM and ANN. • NSGA-II suggests that the best point on the curve is where it reaches its minimum. • Based on RSM, Biofilm growth and lipid production were significant at 3% CO 2. • Compared to the RSM, ANN was more predictive of CO 2 concentration increases. • An ANN has an R2 of 9.96E-01, an R-value of 9.98E-01, and MAE of 1.62E-03 and MSE of 2.62E-02. [ABSTRACT FROM AUTHOR]

Dealing with the current defaults of environmental toxicity, heating, waste management, and economic crises, exploration of novel non-edible, toxic, and waste feedstock for renewable biodiesel synthesis is the need of the hour. The present study is concerned with Buxus papillosa with seeds oil concentration (45% w/w), a promising biodiesel feedstock encountering environmental defaults and waste management; in addition, this research performed simulation based-response surface methodology (RSM) for Buxus papillosa bio-diesel. Synthesis and application of novel Phyto-nanocatalyst bimetallic oxide with Buxus papillosa fruit capsule aqueous extract was advantageous during transesterification. Characterization of sodium/potassium oxide Phyto-nanocatalyst confirmed 23.5 nm nano-size and enhanced catalytic activity. Other characterizing tools are FTIR, DRS, XRD, Zeta potential, SEM, and EDX. Methyl ester formation was authenticated by FTIR, GC-MS, and NMR. A maximum 97% yield was obtained at optimized conditions i.e., methanol ratio to oil (8:1), catalyst amount (0.37 wt%), reaction duration (180 min), and temperature of 80 °C. The reusability of novel sodium/potassium oxide was checked for six reactions. Buxus papillosa fuel properties were within the international restrictions of fuel. The sulphur content of 0.00090% signified the environmental remedial nature of Buxus papillosa methyl esters and it is a highly recommendable species for biodiesel production at large scale due to a t huge number of seeds production and vast distribution. [Display omitted] • A novel biodiesel feedstock with 45% oil content has been proven to be buxus papillosa. • A novel green bimetallic catalyst with 0.37 wt% yielded 97% BPBD. • Buxus papillosa biodiesel has pollution-free and eco-friendly properties. • Buxus papillosa seed oil's successful conversion to bio-diesel was ascertained by FT-IR, GC/MS. • Buxus papillosa bio-diesel has fuel physical qualities compatible with international fuel restrictions. [ABSTRACT FROM AUTHOR]

Elemental sulfur autotrophic denitrification (S0AD) processes are temperature-sensitive, presenting a substantial challenge for the practical implementation of S0AD bioreactors. In this study, a comprehensive methodology for designing and operating S0AD bioreactors was developed, effectively managing fluctuations in nitrogen removal efficiency caused by seasonal temperature variations. Initially, the nitrate removal rate was correlated with simulated on-site temperature and nitrate loading, revealing correlation coefficients of k 1 , k 2 , k 3 , and A as 5.42 × 10 − 4 , −0.41, 0.04, and 0.13, respectively, to establish a mathematical model for predicting S0AD efficiency. Subsequently, by considering influence factors such as dissolved oxygen and dynamic sulfur consumption, the model was employed to accurately design a pilot-scale S0AD bioreactor for a case study. By utilizing an alternative multi-subunit operation, a stable effluent nitrate concentration of less than 8 mg-N/L was maintained throughout the year. Importantly, this approach resulted in a substantial reduction of 76.8% in excessive nitrate removal, sulfur consumption, and sulfate production. This study aims to provide an optimal design and operation strategy for the practical application of S0AD bioreactors, thereby enhancing reliability and cost-effectiveness in the face of seasonal temperature changes. • A mathematical model correlating temperature, nitrate loading, and nitrate removal rate was developed. • A multi-subunit strategy guided by model prediction was applied in a pilot-scale S0AD bioreactor. • Compliant nitrate removal across annual temperature range was achieved by multi-subunit operation. • Substantial reduction in excessive sulfur consumption and sulfate production was achieved. [ABSTRACT FROM AUTHOR]

To reuse water and reduce water pollution, such as chemical oxygen demand (COD), total suspended solids (TSS), PO 4 , NTU, and NO 3 , advanced wastewater treatment technologies (a combination of coagulation (FeCl 3) and adsorption (Activated Carbon (AC))) are attractive. Considering that water reclamation can help provide an irrigation system for crops and domestic purified water, removing organic matter and nutrients prior to wastewater reuse is fundamental. In order to remove contaminants like organic matter and nutrients from wastewater, advanced wastewater treatment processes are recommended. The purpose of this paper is to investigate various doses of AC and FeCl 3 in wastewater treatment and study the optimum conditions for the removal of COD, TSS, PO 4 , NTU, and NO 3. Furthermore, the evaluated FeCl 3 '/AC's optimum functioning pH ranges from 6.5 to 8.0, and their optimum working times range from 2.5 to 5.5 h. The optimum concentrations of AC were 0.1–25 g/L and 0.1–5 g/L of FeCl3. The most significant COD elimination rate (98%), the highest TSS elimination efficiency (94%), NTU elimination performance (99%), PO4 elimination (99%), and NO3 elimination (67%), among the investigated FeCl 3 and AC. Secondly, the effects of operational variables such as AC, FeCl 3 , time, and solution pH were modeled, optimized, and evaluated using response surface techniques based on the D-Optimal design. Input from the response surface approach findings was used to develop an artificial neural network-based prediction model and Non-dominated Sorting Genetic Algorithm II (NSGA-II). [Display omitted] • COD, TSS, PO4, NTU, and NO3 were effective FeCl3 and PAC coagulants at optimal conditions. • Co-degradation outputs are compared to experimental results using ANNs and RSMs. • The RSM correlation coefficient was 0.973 and the ANN correlation coefficient was 0.997. • Activated carbon and FeCl3 are suitable technologies for the decline of organic matter in advanced water treatment. [ABSTRACT FROM AUTHOR]

The recovery of phosphorus (P) through vivianite crystallization offers a promising approach for resource utilization in wastewater treatment plants. However, this process encounters challenges in terms of small product size and low purity. The study aimed to assess the feasibility of using quartz sand as a seed material to enhance P recovery and vivianite crystal characteristics from anaerobic fermentation supernatant. Various factors, including seed dosage, seed size, Fe/P ratio, and pH, were systematically tested in batch experiments to assess their influence. Results demonstrated that the effect of seed enhancement on vivianite crystallization was more pronounced under higher seed dosages, smaller seed sizes, and lower pH or Fe/P ratio. The addition of seeds increased P recovery by 4.43% in the actual anaerobic fermentation supernatant and also augmented the average particle size of the recovered product from 19.57 to 39.28 μm. Moreover, introducing quartz sand as a seed material effectively reduced co-precipitation, leading to a notable 12.5% increase in the purity of the recovered vivianite compared to the non-seeded process. The formation of an ion adsorption layer on the surface of quartz sand facilitated crystal attachment and growth, significantly accelerating the vivianite crystallization rate and enhancing P recovery. The economic analysis focused on chemical costs further affirmed the economic viability of using quartz sand as a seed material for P recovery through vivianite crystallization, which provides valuable insights for future research and engineering applications. [Display omitted] • Quartz sand as seed material increased P recovery in anaerobic fermentation supernatant. • Seed-induced vivianite crystallization was enhanced at higher seed doses, smaller seed sizes, and lower pH or Fe/P ratios. • Quartz sand as seed material improved vivianite purity through reduced co-precipitation. • Quartz sand as seed material for vivianite crystallization was economically feasible. [ABSTRACT FROM AUTHOR]

Sulfur-packed beds (SPBs) have been increasingly incorporated into constructed wetland systems to overcome limitations in achieving satisfactory nitrate removal efficiency. However, the underlying impact of hydraulic regimes on SPB performance remains understudied. This study investigated the performance of a pilot-scale SPB, encompassing sulfur autotrophic denitrification (SAD) and sulfur disproportionation (SDP) processes, under various horizontal flow (HF) and vertical flow (VF) regimes. The HF regime exhibited superior SAD efficiency, achieving 3.1–4.4 mg-N/L of nitrate removal compared to 0.9–2.8 mg-N/L under VF regimes. However, greater sulfide production of 3.8–5.6 mg/L was observed, in contrast to only 1.5–2.3 mg/L under VF regimes when SDP occurred. Employing current computational fluid dynamics simulations could predict general regimes but lacked precision in detailing sulfur layer dynamics. In contrast, determining the spatial distribution of SAD substrates and SDP products offered a viable solution, revealing stagnate, short-circuit, and back flows. Moreover, the feasibility of an aeration approach to reduce sulfide emissions below 0.5 mg/L in case of accidental SDP occurrence was confirmed. This study offers a method for assessing detailed hydraulic regimes within SPBs. Additionally, it provides guidance on optimizing the packing of sulfur-based materials when implementing SPBs in constructed wetland systems and presents a strategy for mitigating excessive sulfide emissions. [Display omitted] • SAD and SDP processes were alternatively achieved in a pilot-scale SPB. • The detailed hydraulic regimes within the sulfur layer were determined. • Horizontal flow improved SAD efficiency but concurrently elevated SDP risk. • Equipping aeration devices was suggested to address sudden spikes in SDP. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) are attractive functional materials due to their high surface area, high porosity, and flexible compositions. However, the high precursor cost and complex synthetic processes hinder their large-scale applications. Herein, a novel green approach has been developed toward the synthesis of Cu-based MOF by a solvent-free mechano-synthesis method and utilizing consumed polyethylene terephthalate (PET)-derived benzenedicarboxylate (BDC) as the linker. The as-prepared CuBDC and aminated CuBDC (CuBDC-NH 2) act as green catalysts for the reduction of deleterious 4-nitrophenol (4-NP) into the value-added 4-aminophenol (4-AP). Compared with CuBDC, CuBDC-NH 2 shows increased adsorption capability and reduction efficiency. The mechanism and thermodynamic studies suggest that the adsorption of 4-NP on CuBDC-NH 2 is an endothermic, spontaneous, favorable, and physical adsorption process. Furthermore, CuBDC-NH 2 can expedite the reduction of 4-NP by participating in an adsorptive catalytic process. With the CuBDC-NH 2 catalyst, the catalytic normalized kinetic rate of 4-NP was achieved 11.28 mol/min. mg, outperforming state-of-the-art catalysts, and a complete reduction occur in 5 min for a concentrated effluent (200-ppm 4-NP). The plastic waste-derived MOF-mediated catalytic valorization of organic pollutants demonstrated here opens an avenue for the green recycling/utilization of plastic waste, providing meaningful insights into the sustainable management of organic pollutants in wastewater. [Display omitted] • Modified alkaline hydrolysis extraction of high-quality PET-derived BDC in a novel rotary autoclave • Solvent-free green synthesis of waste PET-derived CuBDC • High 4-NP adsorption capacity of green CuBDC-NH 2 • Achieving comparative high instantaneous efficiency in the reduction of 4-NP to 4-AP • Meticulous mechanism study of adsorptive catalytic reduction of 4-NP [ABSTRACT FROM AUTHOR]

Medium-chain fatty acids (MCFAs) have drawn great attention due to their high energy density and superior hydrophobicity. Waste activated sludge (WAS) has been documented as a renewable feedstock for MCFAs production via anaerobic fermentation. However, MCFAs production from WAS depends on exogenous addition of electron donor (ED, e.g., lactate) for chain elongation (CE) bioprocess, which results in increased economic cost and limited practical application. In this study, a novel biotechnology was proposed to produce MCFAs from WAS with in-situ self-formed lactate by inoculating Yoghurt starter powder containing with Lactobacillales cultures. The batch experimental results revealed that the lactate was in-situ generated from WAS and the maximum production of MCFAs increased from 1.17 to 3.99 g COD/L with the increased addition of Lactobacillales cultures from 6✕107 to 2.3✕108 CFU/mL WAS. In continuous long-term test over 97 days, average MCFA production reached up to 3.94 g COD/L with a caproate yield of 82.74% at sludge retention time (SRT) 12 days, and the average MCFA production increased to 5.87 g COD/L with 69.28% caproate and 25.18% caprylate at SRT 15 days. A comprehensive analysis of the metagenome and metatranscriptome demonstrated that the genus of Lactobacillus and Streptococcus were capable of producing lactate from WAS and upgrading to MCFAs. Moreover, another genus, i.e., Candidatus Promineofilum , was firstly revealed that it might be responsible for lactate and MCFAs production. Further investigation of related microbial pathways and enzyme expression suggested that D-lactate dehydrogenase and pyruvate ferredoxin oxidoreductase contributed to lactate and acetyl-CoA production, which were the crucial steps for MCFAs generation and were most actively expressed. This study provides a conceptual framework of MCFAs from WAS with endogenous ED, potentially enhancing the energy recovery from WAS treatment. [Display omitted] • MCFA production from WAS with in-situ self-formed lactate was achieved. • MCFA production was positively related to inoculated Lactobacillales cultures level. • The SRT of 15 days was preferable for MCFA production than the SRT of 12 days. • Key microorganisms were revealed to contribute to lactate and MCFA productions. [ABSTRACT FROM AUTHOR]

Peroxymonosulfate (PMS)-mediated advanced oxidation processes gain growing attention in degrading antibiotics (e.g., tetracycline (TC)) in wastewater for their high capacity and relatively low cost, while designing efficient catalysts for PMS activation remains a challenge. In this study, a sulfur-doped Fe/C catalyst (Fe@C–S) synthesized from iron metal-organic frameworks (Fe-MOFs) was developed for PMS activation towards TC removal. Under optimal conditions, the TC removal efficiency of Fe@C–S150/PMS system within 40 min was 91.2%. Meanwhile, the k value for Fe@C–S150/PMS system (0.2038 min−1) was 3.36-fold as high as the S-free Fe@C-based PMS system. Also, Fe@C–S150/PMS system showed high robustness in different water matrices. Further studies found that the TC degradation mechanism was mainly ascribed to the non-radical pathway (1O 2 and electron transfer). Fe nanoparticles, S and C O groups on the catalyst all participated in the generation of reactive oxygen species (ROS). Besides, S species could enhance the Fe2+/Fe3+ redox cycle and accelerate the electron transfer process. This work highlights the critical role of S in enhancing the catalytic performance of Fe/C-based catalysts for PMS activation, which would provide meaningful insights into the design of high-performance PMS activators for the sustainable remediation of emerging contaminants-polluted water bodies. [Display omitted] • S-doped Fe/C composite was designed for PMS activation towards TC degradation. • Fe@C–S150/PMS exhibited good TC removal performance in surface water. • Dominant non-radical mechanism (1O 2 and e− transfer) was elucidated. • Fe species, S and C O groups were active sites for PMS activation. [ABSTRACT FROM AUTHOR]

In this work, a model framework was constructed to assess and predict nitrous oxide (N 2 O) production, substrate and microbe interactions in an anammox biofilm bioreactor. The anammox kinetics were extended by including kinetics of autotrophic soluble microbial products (SMP) formation, which consisted of utilization-associated products (UAP) and biomass-associated products (BAP). Heterotrophic bacteria growing on UAP, BAP and decay released substance (SS) were modelled to perform four-step sequential reductions from nitrate to dinitrogen gas. N 2 O was modelled as an intermidiate of heterotrophic denitrification via three pathways with UAP, BAP and SS as the electron donors. The developed model framework was evaluated using long-term operational data from an anammox biofilm reactor and satisfactorily reproduced effluent nitrogen and SMP as well as N 2 O emission factors under different operational conditions. The modeling results revealed that N 2 O was mainly produced with UAP as the electron donor while BAP and SS play minor roles. Heterotrophic denitrifiers growing on UAP would significantly contribute to N 2 O emission from anammox biofilm reactor even though heterotrophs only account for a relatively small fraction of active biomass in the anammox biofilm. Comprehensive simulations were conducted to investigate the effects of N loading rate and biofilm thickness, which indicated that maintaining a low N loading rate and a thick biofilm thickness were essential for high total nitrogen removal efficiency and low N 2 O emission. Image 1 • The model describes SMP production and three N 2 O pathways in anammox biofilm. • N 2 O via UAP serves as the main pathway, while BAP and SS pathways play minor roles. • SMP increased with decreasing N loading and increasing biofilm thickness. • A low N loading and a thick biofilm are crictial for high TN removal and low N 2 O. [ABSTRACT FROM AUTHOR]

Vivianite crystallization has been regarded as a suitable option for recovering phosphorus (P) from P-containing wastewater. However, the presence of humic substances (HS) would inevitably affect the formation of vivianite crystals. Therefore, the influences of HS on vivianite crystallization and the changes in the harvested vivianite crystals were investigated in this study. The results suggested the inhibition effect of 70 mg/L HS on vivianite crystallization reached 12.24%, while it could be attenuated by increasing the pH and Fe/P ratio of the solution. Meanwhile, the addition of HS altered the size, purity, and morphology of recovered vivianite crystals due to the blockage of the growth sites on the crystal surface. Additionally, the formation of phosphate ester group, hydrogen bonding, and COOH–Fe2+ complexes are the potential mechanisms of HS interaction with vivianite crystals. The results obtained herein will help to elucidate the underlying mechanism of HS on vivianite crystallization from P-containing wastewater. [Display omitted] • Humic substances (HS) inhibited phosphorus recovery and vivianite growth. • The presence of HS changed size, morphology, and purity of vivianite crystals. • Increasing pH and Fe/P ratio mitigated the inhibitory effect of HS on vivianite crystallization. • Phosphate ester group, hydrogen bonding, and COOH–Fe2+ complexes were mainly responsible for the interaction. [ABSTRACT FROM AUTHOR]

Heterojunction-driven photocatalysis can degrade various organic pollutants, and developing carbon nitride-based composite photocatalysts is of great significance and gains growing interest. In this study, a two-dimensional graphitic carbon nitride nanosheets/BiFeO 3 (GCNNs/BiFeO 3) Z-scheme heterojunction has been synthesized through the electrostatic spinning and post-calcination The obtained GCNNs/BiFeO 3 nanofibers show large surface contact between GCNNs the and BiFeO 3 nanostructures. The Z-scheme heterojunction shows a remarkably enhanced photocatalytic performance, which could degrade 94% of tetracycline (TC) and 88% of Rhodamine B (RhB) under LED visible light irradiation in 150 min. Radical trapping experiments demonstrate the effective construction of Z-scheme heterojunctions, and •O 2 − and h+ are the main active species in the photocatalytic degradation process. This study realizes a novel nanostructured GCNNs/BiFeO 3 heterojunction for photodegradation applications, which would guide the design of next-generation efficient photocatalysts. • Ionic liquid modification of bulk C 3 N 4 to obtain GCNNs with improved dispersion. • GCNNs/BiFeO 3 nanofibers Z-scheme heterojunction are constructed by electrospinning. • Large contact area effectively promotes the transfer of photogenerated carriers. • BC-4 could degrade 94% of TC and 88% of RhB under LED visible light. [ABSTRACT FROM AUTHOR]

High-silica phosphogypsum (PG) is a kind of industrial by-product with great utilization potential. However, it is difficult to reuse PG directly due to the related gangue minerals (e.g., SiO 2), and thus efficient purification is required to allow its further applications. Herein, a typical high-silica phosphogypsum waste was purified by a new "reverse-direct flotation" method. The organic matters and fine slimes were removed by reverse flotation, and then, the silica impurity was removed by direct flotation. Via the closed-circuit flotation process, the whiteness of the PG concentrate is improved from 33.23 to 63.42, and the purity of gypsum in the PG concentrate increases from 83.90% to 96.70%, with a gypsum recovery of 85%. Additionally, the content of SiO 2 is significantly reduced from 11.11% to 0.07%. In-depth investigations suggest that the difference in the floatability of gypsum and quartz is prominently intensified by flotation reagents at pH = 2–2.5, and thus leads to good desilication performance. Further characteristics of the PG concentrate prove that impurities have been well removed, and the PG concentrate meets the requirement of related standards for gypsum building materials. The flotation method reported here paves the way for the purification of high-silica phosphogypsum, which can be extended to the purification and value-added reutilization of other industrial solid wastes. [Display omitted] • The "reverse-direct flotation" method effectively purifies the waste PG. • The surface of gypsum crystals after flotation purification is clean and smooth. • Flotation purification of waste PG can obtain huge environmental and economic benefits. [ABSTRACT FROM AUTHOR]

Food waste (FW) is not only a major social, nutritional and environmental issue, but also an underutilized resource with significant energy, which has not been fully explored currently. Considering co-digestion can adjust carbon to nitrogen ratio (C/N) of the feedstock and improve the synergetic interactions among microorganisms, anaerobic co-digestion (AnCoD) is then becoming an emerging approach to achieve higher energy recovery from FW while ensuring the stability of the system. To obtain higher economic gain from such biodegradable wastes, increasing attention has been paid on optimizing the system configuration or applying enzymatic hydrolysis before digesting FW. A better understanding on the potentiality of correlating enzymatic pretreatment and AnCoD operated in various system configuration would enhance the bioresource recovery from FW and increase revenue through treating this organic waste. Specifically, the biobased chemicals outputs from FW-related co-digestion system with different configuration were firstly compared in this review. A deep discussion concerning the challenges for achieving bioresources recovery from FW co-digestion systems with enzymatic pretreatment was then given. Recommendations for future studies regarding FW co-digestion were then proposed at last. • Bioenergies recovered from FW co-digestion system were evaluated. • Multi-phase system performed better in energy recovery from FW via co-digestion. • Strategies for coping high cost for enzymatic pretreatment were proposed. • Coupling enzymatic pretreatment with co-digestion induced higher energy recovery. [ABSTRACT FROM AUTHOR]

Excess sludge management is a restrictive factor for the development of municipal wastewater treatment plants. The addition of metabolic uncouplers has been proven to be effective in sludge reduction. However, the long-term effect of metabolic uncoupler o-chlorophenol (oCP) on the biological wastewater treatment system operated in anaerobic-oxic mode is still unclear. To this end, two parallel reactors operated in anaerobic-oxic mode with and without 10 mg/L of oCP addition were investigated for 91 days. The results showed that 56.1 ± 2.3% of sludge reduction was achieved in the oCP-added system, and the nitrogen and phosphorus removal ability were negatively affected. Dosing oCP stimulated the formation of microbial products and increased the DNA concentration, but resulted in a decrease in the electronic transport activity of activated sludge. Microbial community analysis further demonstrated that a significant reduction of bacterial richness and diversity occurred after oCP dosing. However, after stopping oCP addition, the pollutant removal ability of activated sludge was gradually increased, but the sludge yield, as well as species richness and diversity, did not recover to the previous level. This study will provide insightful guidance on the long-term application of metabolic uncouplers in the activated sludge system. [Display omitted] • Sludge reduction of 56.1% was achieved in the o-chlorophenol (oCP)-added system. • oCP addition stimulated the microbial products formation of activated sludge. • The species richness and diversity were reduced with oCP addition. • The sludge yield, as well as species richness and diversity, did not recover after stopping oCP addition. [ABSTRACT FROM AUTHOR]

Metal-laden solid wastes (e.g., waste graphite powders) have attracted great attention owing to their hazardous effects on the surrounding soil and water. Additionally, the metal-bearing impurities also hinder the reutilization of waste graphite powders. Thus, it is necessary to remove these inorganic impurities and figure out the removal mechanism of impurities in the purification process. In this study, an alkaline roasting-water washing-acid leaching (AWA) method was used to upgrade the waste graphite powders, and the migration behavior of diverse impurities has been qualitatively and quantitatively investigated. A graphite product with high impurity removal efficiencies is attained under optimal conditions. The removal of impurities mainly follows three routes: (1) V-, P-, and S-bearing impurities were complete removed (some formed soluble salts during alkaline roasting, and the remainder was dissolved in acid); (2) most Al-, K-, and Si-bearing impurities were removed by alkaline roasting, with the remainder was dissolved in the acid-leaching process; and (3) Fe-, Mg-, Ti-, Ca-, and Zn-bearing impurities were decomposed at high temperature and reacted with alkali to form hydroxides or oxides, which was subsequently dissolved in acid. In addition, the treatment of the generated wastewater is also discussed. The uncovered migration mechanisms of diverse impurities would guide the purification and reutilization process of other metal-bearing solid wastes efficiently. • Graphite wastes were purified by alkali roasting-water washing-acid leaching. • Graphite products with a fixed carbon content of 99.96% were obtained. • The migration mechanisms of impurities are studied qualitatively and quantitatively. [ABSTRACT FROM AUTHOR]

The development of highly efficient photocatalysts is crucial for the remediation of organic pollutants. Herein, we reported a facile synthesis of oxygen vacancy rich Bi(OH)SO 4 ·H 2 O photocatalyst by the control of precursor. The samples were characterized by XRD, scanning electron microscope, electron paramagnetic resonance, X-ray photoelectron spectroscopy etc. With more oxygen vacancies introduced, the photocatalytic activity on the degradation of RhB and tetracycline was significantly boosted. Density functional theory calculation was used to further reveal the influence of oxygen vacancy on the band structure of Bi(OH)SO 4 ·H 2 O. The results and finding of this work are helpful for the development of sustainable environmental protection. • Bi(OH)SO 4 ·H 2 O with controllable oxygen vacancies prepared by a facile method. • The photocatalytic activity on the degradation of organic pollutants was significantly increased. • The influence of oxygen vacancy on band structure was revealed. [ABSTRACT FROM AUTHOR]

Rotaviruses (RV) are a common cause of severe diarrhea in young children, resulting in nearly one million deaths worldwide annually. Rotavirus VP7 was the rotavirus neutralizing protein. Previous study reported that VP7 DNA vaccine can induce high levels of IgG in mice but cannot protect mice against challenge (Choi, A.H., Basu, M., Rae, M.N., McNeal, M.M., Ward, R.L., 1998. Virology 250, 230–240). We found that rotavirus VP7 could maintain its neutralizing immunity when it was transformed into the potato genome. Mice immunized with the transformed tubers successfully elicited serum IgG and mucosal IgA specific for VP7. The mucosal IgA titer was as high as 1000, while serum IgG titer was only 600. Neutralizing assays indicated that IgA could neutralize rotavirus. These results indicate the potential usefulness of plants for production and delivery of edible rotavirus vaccines. [Copyright &y& Elsevier]

Clarithromycin retained in waste activated sludge (WAS) inevitably enters the anaerobic digestion system. So far, the complex impacts and fate of clarithromycin in continuous operated WAS anaerobic digestion system are still unclear. In this study, two semi-continuous long-term reactors were set up to investigate the effect of clarithromycin on biogas production and antibiotic resistance genes (ARGs) during WAS anaerobic digestion, and a batch test was carried out to explore the potential metabolic mechanism. Experimental results showed that clarithromycin at lower concentrations (i.e., 0.1 and 1.0 mg/L) did not affect biogas production, whereas the decrease in biogas production was observed when the concentration of clarithromycin was further increased to 10 mg/L. Correspondingly, the relative abundance of functional bacteria in WAS anaerobic digestion (i.e., Anaerolineaceae and Microtrichales) was reduced with long-term clarithromycin exposure. The investigation of ARGs suggested that the effect of methylation belonging to the target site modification played a critical role for the anaerobic microorganisms in the expression of antibiotic resistance, and ermF , played dominated ARGs, presented the most remarkable proliferation. In comparison, the role of efflux pump was weakened with a significant decrease of two detected efflux genes. During WAS anaerobic digestion, clarithromycin could be partially degraded into metabolites with lower antimicrobial activity including oleandomycin and 5-O-desosaminyl-6-O-methylerythronolide and other metabolites without antimicrobial activity. • Clarithromycin inhibited biogas production from WAS anaerobic digestion. • Most methylase ARGs in digested sludge were increased after clarithromycin exposure. • Clarithromycin was partially degraded after anaerobic digestion. • Oleandomycin (m/z 671 and m/z 590) were the main metabolites of clarithromycin. [ABSTRACT FROM AUTHOR]

Bisphenol A (BPA) is a toxic environmental pollutant commonly found in wastewater. Using non-toxic materials and eco-friendly technology to remove this pollutant from wastewater presents multiple advantages. Treatment of wastewater with clay minerals has received growing interest because of the environment friendliness of these materials. Bentonite is a 2:1 layered phyllosilicate clay mineral that can support nano-metal catalysts. It can prevent the agglomeration of nano-metal catalysts and improve their activity. In this article, a green catalytic nano zero-valent iron/bentonite composite material (NZVI@bentonite) was synthesized via liquid-phase reduction. The average size of NZVI was approximately 40–50 nm. Good dispersion and low aggregation were observed when NZVI was loaded on the surface or embedded into the nanosheets of bentonite. Degradation of BPA, a harmful contaminant widely found in wastewater at relatively high levels, by NZVI@bentonite was then investigated and compared with that by pristine NZVI through batch Fenton-like reaction experiments. Compared with pristine NZVI and bentonite alone, the NZVI@bentonite showed a higher BPA degradation ratio and offered highly effective BPA degradation up to 450 mg/g in wastewater under optimum operating conditions. Adsorption coupled with the Fenton-like reaction was responsible for BPA degradation by NZVI@bentonite. This work extends the application of NZVI@bentonite as an effective green catalyst for BPA degradation in aqueous environments. Image 1 • Bentonite-supported nano-zero-valent iron (NZVI@bentonite) were synthesized. • The synthesized composite NZVI@bentonite was characterized in detail. • The degradation ratio for bishphenol A (BPA) in wastewater were studied. • The degradation mechanisms of BPA by NZVI@bentonite were discussed. • NZVI@bentonite affords highly effective degradation of BPA 450 mg/g. [ABSTRACT FROM AUTHOR]