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[Display omitted] • Hydrodynamics affect vivianite precipitation and agglomeration processes. • Stirring improved crystal growth over aeration by offering homogeneous mixing. • Higher shear rates in stirring systems yield larger crystals and improved settling. • Particle Imaging Velocimetry characterizes vivianite crystals in turbulent flows. • Hydrodynamic-vivianite correlations inform phosphorus recovery optimization. Hydrodynamic conditions have an essential influence on the precipitation and agglomeration processes of crystals. However, the influence of hydrodynamics under different operating conditions on vivianite crystallization is commonly ignored in the phosphorus recovery process. To this purpose, the effects of hydrodynamics on vivianite properties in stirring and aeration systems were investigated with the aid of particle image velocimetry (PIV). Hydrodynamic parameters of shear rate (G), flow velocity, Kolmogorov microscale (η), turbulent dissipation rate (ε), and turbulent kinetic energy (k) were calculated, and the generated vivianite properties were recorded. The analysis of flow field distribution showed that the mixing state under the stirring system was more homogeneous and formed a smaller hydraulic dead zone, which may be more favorable for the formation and growth of crystals. Compared with the aeration system at the same G , the stirring system has higher hydrodynamic parameters, producing stronger turbulent intensity and higher shear rate. The higher recovery efficiency, as well as larger crystal size in the stirring system, demonstrated that higher shear rates (95–309 s−1) increased the crystallization rate, ultimately improving the crystal size and settling performance. Significant relationships between hydrodynamic parameters and the harvested crystal size showed that the flow velocity, η , ε , and k were suitable hydrodynamic parameters for evaluating the growth of vivianite. This work is expected to provide the theoretical basis and technical support for the design and operation of vivianite recovery reactors. [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]

Background: Systemic lupus erythematosus (SLE) is a multisystemic, chronic inflammatory disease characterized by destructive systemic organ involvement, which could cause the decreased functional capacity, increased morbidity and mortality. Previous studies show that SLE is characterized by autoimmune, inflammatory processes, and tissue destruction. Some seriously-ill patients could develop into lupus nephritis. However, the cause and underlying molecular events of SLE needs to be further resolved.Methods: The expression profiles of GSE144390, GSE4588, GSE50772 and GSE81622 were downloaded from the Gene Expression Omnibus (GEO) database to obtain differentially expressed genes (DEGs) between SLE and healthy samples. The gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichments of DEGs were performed by metascape etc. online analyses. The protein-protein interaction (PPI) networks of the DEGs were constructed by GENEMANIA software. We performed Gene Set Enrichment Analysis (GSEA) to further understand the functions of the hub gene, Weighted gene co-expression network analysis (WGCNA) would be utilized to build a gene co-expression network, and the most significant module and hub genes was identified. CIBERSORT tools have facilitated the analysis of immune cell infiltration patterns of diseases. The receiver operating characteristic (ROC) analyses were conducted to explore the value of DEGs for SLE diagnosis.Results: In total, 6 DEGs (IFI27, IFI44, IFI44L, IFI6, EPSTI1 and OAS1) were screened, Biological functions analysis identified key related pathways, gene modules and co-expression networks in SLE. IFI27 may be closely correlated with the occurrence of SLE. We found that an increased infiltration of moncytes, while NK cells resting infiltrated less may be related to the occurrence of SLE.Conclusion: IFI27 may be closely related pathogenesis of SLE, and represents a new candidate molecular marker of the occurrence and progression of SLE. Moreover immune cell infiltration plays important role in the progession of SLE. [ABSTRACT FROM AUTHOR]

The synthesis of ammonia via the Haber–Bosch process requires high temperature and high pressure, which causes about 1.6% of global CO2 emission every year. the development of a low-cost, facile ammonia synthesis method under ambient conditions is urgently required. Herein, we employed a facile approach to prepare defective g-C3N4 nanorods with a narrower bandgap and a sub-gap, which can significantly enhance the light utilization ratio. More importantly, the defects of g-C3N4 nanorods can also enhance the light adsorption and boost cleavage of N2 molecules, which is the rate-determining step of nitrogen fixation. Compared with bulk g-C3N4, the photocatalytic N2 reduction rate of defective g-C3N4 nanorods as the catalysts was increased by 3.66 times. According to the density functional theory calculation results, the active sites should be an extra carbon in the ring formed in s-triazine rings. This work may provide in-depth insights into the development of novel defective photocatalysts for N2 fixation. [ABSTRACT FROM AUTHOR]

Hypotrichs are a highly differentiated and very diverse group of ciliated protists. Their systematics and taxonomy are challenging and call for detailed investigations on their general morphology, ultrastructure, ontogenesis, and molecular phylogeny. Here, a comprehensive study is conducted on a brackish water population of Parabistichella variabilis using light and electron microscopy and phylogenetic analyses based on small subunit ribosomal DNA sequence data. Its morphology, including the infraciliature, pellicle, nuclei, buccal seal, and extrusomes, is documented. The present findings indicate that in P. variabilis: (i) the cortical granules are extrusomes, which differ from those of other hypotrichs; (ii) the buccal seal is bounded by the plasma membrane and contains a single layer of longitudinal microtubules; (iii) two contractile vacuoles might be present rather than one; and (iv) the pharyngeal disks are bounded by a single membrane. Early‐to‐middle stages of ontogenesis are described for the first time, enabling the complete characterization of this process. Phylogenetic analyses indicate that Parabistichella variabilis is closely related to several species from different genera, such as Orthoamphisiella breviseries, Uroleptoides magnigranulosus, and Tachysoma pellionellum. However, ultrastructural and gene sequence data for more taxa are needed in order to resolve the systematics of Parabistichella. [ABSTRACT FROM AUTHOR]

Previous studies using mouse liver tumor models have indicated that coexpression of CD38 and CD101 in programmed cell death-1 (PD-1)+CD8+ T cells may reflect fixed dysregulation of CD8+ T cells and thus indicate a poor response to anti-PD-1 immunotherapy. However, whether CD38 and CD101 expression in PD-1+CD8+ T cells can predict the clinical status and efficacy of chemotherapy for various cancer types, including ovarian cancer (OC), remains unclear. In the present study, peripheral blood mononuclear cells (PBMCs) were obtained by Ficoll-Hypaque gradient centrifugation from 96 fresh samples from healthy adult volunteers and patients with epithelial OC, aged 55.21±9.91 years. Additionally, tumor-infiltrating lymphocytes (TILs) were separated using a combination of mechanical, chemical and enzymatic digestion from fresh surgically removed tumor tissues from 15 patients with epithelial OC. The expression of CD38 and CD101 in PD-1+CD8+ T cells or TILs was detected by flow cytometry or immunofluorescence (IF) staining, respectively. The association between the level of CD38/CD101 expression and clinicopathological parameters or postoperative chemotherapy in patients with OC was statistically analyzed. The levels of CD38/CD101-coexpressing PD-1+CD8+ T cells were significantly increased in PBMCs and TILs of patients with OC compared with those of healthy volunteers. The frequency of PD-1+CD38+CD101+CD8+ T cells among the total PD-1+CD8+ T cell subpopulation was negatively associated with clinical stage, lymph node metastasis and postoperative chemotherapy prognosis in patients with OC. Furthermore, IF staining confirmed colocalization of CD38 and CD101 on the majority of TILs in OC tissues. Thus, the present study suggests that coexpression of CD38 and CD101 in peripheral PD-1+CD8+ T cells and TILs may serve as a new indicator for diagnosis and treatment efficacy in patients with epithelial OC. [ABSTRACT FROM AUTHOR]

Defects can influence the properties of photocatalysts, and defective ZnO has triggered broad interest and intensive studies for decades. However, the correlation between crystal planes and defects remains unclear. Here, we demonstrate that the (101) plane is superior in producing oxygen vacancies than the (100) plane in rod-like defective ZnO samples. While the optimum intensity of the crystal ratio, (101)/(100), approaches 1, the separation efficiency of electrons–holes is much enhanced. Furthermore, it is found that the (101) plane has stronger spontaneous adsorption and higher dissociation activity of H2O, which is conducive to the spontaneous formation of oxygen vacancies and eventually enhances the separation efficiency of electrons–holes. The charge difference also shows that the crystal boundary junctions could cause uneven charge distribution, inducing lattice polarization and boosting the charge separation of defective ZnO, which is helpful for improving the photocatalytic activities. As a new proposed mechanism, the relationship between defect engineering and crystal surface could provide inspiration for the design of special nanomaterials for the environment purification and energy fields. [ABSTRACT FROM AUTHOR]

The encystment of many ciliates is an advanced survival strategy against adversity and the most important reason for ciliates existence worldwide. However, the molecular mechanism for the encystment of free-living ciliates is poorly understood. Here, we performed comparative transcriptomic analysis of dormant cysts and trophonts from Pseudourostyla cristata using transcriptomics, qRT-PCR and bioinformatic techniques. We identified 2565 differentially expressed unigenes between the dormant cysts and the trophonts. The total number of differentially expressed genes in GO database was 1752. The differential unigenes noted to the GO terms were 1993. These differential categories were mainly related to polyamine transport, pectin decomposition, cytoplasmic translation, ribosome, respiratory chain, ribosome structure, ion channel activity, and RNA ligation. A total of 224 different pathways were mapped. Among them, 184 pathways were upregulated, while 162 were downregulated. Further investigation showed that the calcium and AMPK signaling pathway had important induction effects on the encystment. In addition, FOXO and ubiquitin-mediated proteolysis signaling pathway jointly regulated the encystment. Based on these findings, we propose a hypothetical signaling network that regulates Pseudourostyla cristata encystment. Overall, these results provide deeper insights into the molecular mechanisms of ciliates encystment and adaptation to adverse environments. [ABSTRACT FROM AUTHOR]

Circular RNAs (circRNAs) represent a newly identified class of non-coding RNAs that have been shown to be involved in several diseases, including autoimmune diseases. Two studies have revealed the aberrant circRNA expression profiles in the peripheral blood mononuclear cells (PBMCs) of patients with rheumatoid arthritis (RA) by microarrays. However, due to the intrinsic defects of microarrays, such as their inability to detect unidentified circRNAs, we examined the circRNA expression profiles in the PBMCs from four RA patients and three healthy controls by RNA sequencing (RNA-seq) and further explored the value of circRNAs in diagnosing RA. The results showed 71 markedly dysregulated circRNAs, including 41 upregulated and 30 downregulated circRNAs; these data included several previously unidentified candidate circRNAs. Gene Ontology and pathway annotation revealed that the most altered pathways and genes were associated with inflammation and transcriptional activity, such as the TNF pathway. The selected dysregulated circRNAs were verified by qRT-PCR in the PBMCs of 32 RA patients and 20 healthy controls, and the results indicated that hsa_circ_0000396 and hsa_circ_0130438 were downregulated in the RA group versus the healthy group, consistent with the RNA-seq data. The area under the receiver operating characteristic curve indicated the diagnostic value of both circRNAs for RA. Our results identified aberrant dysregulated circRNAs in RA patients, including several identified circRNAs, and the diagnostic value of circRNAs for RA, suggesting the superiority of RNA-seq versus microarrays for screening differentially expressed circRNAs and further strengthening the potential diagnostic value of circRNAs for the diagnosis of RA. [ABSTRACT FROM AUTHOR]

Elemental Ag0 is well known for its remarkable catalytic and antibacterial properties, thus the regeneration of valuable Ag0 metal from Ag+ wastewater is of great significance. In this study, a novel polyethylenimine (PEI) modified potassium tungsten oxide (N-K 2 W 4 O 13) adsorbent was prepared for Ag+ removal and reduction to Ag0 using glutaraldehyde as crosslinking agent. XPS and FT-IR spectra verified PEI successfully anchored on the surface O and W atoms of K 2 W 4 O 13 through aldehyde bridges. The content of PEI in N-K 2 W 4 O 13 was calculated as 8.74 wt% by TG curve. A heterogeneous PEI coating was observed in the SEM and TEM images. The N-K 2 W 4 O 13 exhibited larger Ag+ uptake (48.25 mg/g) than the raw K 2 W 4 O 13 (42.50 mg/g) though required a longer equilibrium time. This was due to the combined results of strong chelation and weak electrostatic repulsion that meanwhile occurring on the positive-charged surface of N-K 2 W 4 O 13. The maximum Ag+ uptake on N-K 2 W 4 O 13 was 72.5 mg/g, which was larger than many of the reported adsorbents. Furthermore, the prepared N-K 2 W 4 O 13 displayed good anti-interference toward background ions (Na+, K+) and hold a stable Ag+ removal (>95%) after five runs of recycling tests. The mechanism studies elucidated that NH/ N groups from the PEI modified N-K 2 W 4 O 13 mainly accounted for the Ag+ adsorption and Ag0 recovery in the adsorption-reduction process. Ion-exchange between Ag+ and K+ from the N-K 2 W 4 O 13 lattice also occurred. This work provided a facile method to synthesize a promising adsorbent for Ag+ wastewater remediation and valuable Ag0 recovery. Unlabelled Image • PEI modified K 2 W 4 O 13 (N-K 2 W 4 O 13) was used for Ag+ removal and Ag0 recovery from wastewater. • Strong chelation and weak electrostatic repulsion resulted in larger but slower Ag+ uptake for N-K 2 W 4 O 13. • The maximum Ag+ uptake for N-K 2 W 4 O 13 reached up to 72.5 mg/g; • NH/ N groups in PEI and C O groups in glutaraldehyde accounted for Ag+ uptake and reduction by N-K 2 W 4 O 13. [ABSTRACT FROM AUTHOR]

In this work, a low-cost alternative method (i.e., adding nitrate into WAS) to significantly enhance hydrogen production was reported. Experimental results showed that with an increase of nitrate addition from 0 to 362 mg/L, the maximal hydrogen production from acidic (pH 5.5) fermentation of WAS obviously increased from 12.6 ± 0.5 to 19.3 ± 0.9 mL per gram volatile suspended solids (VSS). The mechanism investigations illustrated more substrates were provided for subsequent hydrogen production. Although the nitrate added inhibited all the biological processes, its inhibition to the hydrogen consumption processes was much severer than that to the hydrogen production processes. The enzyme analyses on the long-term semi-continuous fermenters showed that the nitrate addition slightly inhibited the relative activities of protease, butyrate kinase, acetate kinase, CoA-transferase, and [FeFe] hydrogenase but largely suppressed the relative activities of coenzyme F 420 , carbon monoxide dehydrogenase, and adenylyl sulfate reductase. Image 1 •The presence of nitrate enhanced hydrogen production from waste activated sludge. •Nitrate accelerated the disruption of extracellular polymeric substances. •Nitrate inhibited all the biological processes in anaerobic fermentation. •Inhibition to hydrogen consumption was severer than that to hydrogen production. •A new "closed-loop" concept for the energy cycle of WWTPs was proposed. [ABSTRACT FROM AUTHOR]

Ultrasound has in the past few decades found applications in a variety of disciplines including chemistry, medicine, physics, and to a much less extent microbiology. Our previous studies found that ultrasonic treatment increases the activity of ammonia-oxidizing bacteria (AOB) while suppressing nitrite-oxidizing bacteria (NOB), resulting in beneficial effects in wastewater treatment. In this study, the kinetic and microbiological features of nitrifying microorganisms in activated sludge intermittently treated with ultrasound were investigated to gain an improved understanding of the mechanism involved in ultrasound-induced stimulation of AOB kinetics. The nitrifying microorganisms were initially enriched over 100 days in a laboratory sequential batch reactor (SBR). Ultrasonic treatment of the sludge was then applied with the treatment time in each 12 h SBR cycle progressively increased from 4 to 24 min. Application of the treatment for 21 days led to a doubled maximum specific ammonia oxidation rate, and also the enhanced dominance of known AOB Nitrosomonas genus in the biomass. This stimulatory effect is well described by a modified enzyme catalyzed reaction model, showing a good linear relationship between the natural logarithm value of μ max,AOB and the applied ultrasonic energy density. This result suggests that ultrasonic treatment likely reduced the activation energy of key enzymes involved in ammonium oxidation. Unlabelled Image • Ultrasonic treatment significantly enhances specific ammonia oxidation rate. • Dominance of known AOB Nitrosomonas genus is also enhanced in the biomass. • A modified enzyme catalyzed reaction model is proposed. • A good linear relationship between ln(μ max,AOB) and ultrasonic energy density. • The model can well describe the ultrasonic-assisted ammonia oxidation reaction. [ABSTRACT FROM AUTHOR]

Biomass is a naturally abundant, sustainable and clean resource, which has potential to replace a portion of the finite petroleum and fossil feedstock for sustainable production of value-added chemicals and fuels. However, an efficient conversion process is still difficult to be achieved due to the complex nature of biomass. Currently, the simple, mild, and environmentally benign photocatalytic process appears to be a new research avenue for lignocellulosic biomass transformation. This review provides insights into the state-of-the-art accomplishments in photocatalytic conversion of lignocellulosic biomass and its derivatives, including selective cleavage of dominant bonds of lignin, valorization of processed and native lignin, photoreforming reactions of cellulose and its intermediates, and the depolymerization of robust native lignocellulose under visible or UVA light irradiation. In addition, electricity production from photocatalytic conversion of biomass is also discussed as an innovative lignocellulosic biomass transformation process. We then put forward perspectives for photocatalytic conversion of native lignocellulose and future challenges in increasing the profitability and sustainability of a photocatalysis biorefinery system. [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]

Energy conversion of waste activated sludge alkaline fermentation liquor (WASAFL) to medium-chain fatty acids (MCFAs) is promising for sludge treatment and carbon recovery. However, the single electron donor (ED) fermentation for MCFAs production has irreparable defects. To resolve the respective shortcomings of single electron donor (ED) and improve the MCFAs production efficiency from WASAFL, a novel biotechnical process utilizing ethanol and lactate as co-EDs within different combination ratios were investigated. The results verified that MCFAs production was highest with ethanol to lactate ratio of 1:3 (6988.54 ± 208.18 mg COD/L), being 1.46 and 1.87 times of that with ethanol and lactate as single ED. The kinetic analysis results confirmed that ethanol to lactate ratio of 1:3 resulted in the highest MCFAs yield and formation rate. The microbial taxa results uncovered that the relative abundance of Sphaerochaeta and Haloimpatiens showed positive correlation with MCFAs production. The metabolic pathway analysis indicated that the ethanol oxidization, lactate oxidization, acrylate pathway, reverse β oxidization and fatty acid biosynthesis pathway might take place in the WASAFL fermentation system, contributing to the WASAFL-to-MCFAs conversion. [Display omitted] • Lower ratio of ethanol: lactate promoted MCFAs production from WASAFL. • Higher or equal ratio of ethanol: lactate reduced MCFA production and selectivity. • Under sole ED condition, ethanol is more efficient for MCFA production than lactate with WASAFL as substrate. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ideal influent substrates conditions for n-DAMO/anammox-based granular bioreactor. • Smaller granules rich in n-DAMO archaea/AnAOB accelerated bioreactor start-up. • Low diffusivity of solutes promoted bioreactor start-up and CH 4 utilization. In this work, a bioprocess model was applied to first determine the impacts of influent substrates conditions on the granular bioreactor performing nitrate/nitrite-dependent anaerobic methane oxidation (n-DAMO) and anammox integrated processes and then investigate the roles of granular sludge properties in regulating the bioreactor performance and start-up process. The ideal influent substrates conditions were identified at NO 2 −-N/NH 4 +-N of 1:1 and dissolved CH 4 concentration of 85 g COD m−3, which achieved 98.6% total nitrogen removal and 87.7% dissolved CH 4 utilization. Under such ideal influent conditions, the initial properties of granular sludge didn't significantly affect the granular bioreactor performance. However, inoculation of granular sludge with a relatively small granular sludge size and a high abundance of n-DAMO archaea or/and anammox bacteria could effectively shorten the bioreactor start-up. Meanwhile, reducing the diffusivity of solutes within granular sludge was also beneficial for expediting the start-up process and promoting dissolved CH 4 utilization. [ABSTRACT FROM AUTHOR]

In order to reduce the environmental hazards of red mud (RM) and realize its resource utilization, in this study, RM-based iron-carbon micro-electrolysis material (RM-MEM) were prepared by a carbothermal reduction process using RM as raw material. The influence of the preparation conditions on the phase transformation and structural characteristics of the RM-MEM were investigated during the reduction process. The ability of RM-MEM to remove organic pollutants from wastewater was evaluated. The results showed that RM-MEM prepared at a reduction temperature of 1100 °C, a reduction time of 50 min and a coal dosage of 50% had the best removal effect for the degradation of methylene blue (MB). When the initial MB concentration was 20 mg L−1, the amount of RM-MEM material was 4 g L−1, the initial pH was 7, and the degradation efficiency reached 99.75% after 60 min. When RM-MEM is split into carbon free and iron free parts for use, the degradation effect becomes worse. Compared to other materials, RM-MEM has lower cost and better degradation. X-ray diffraction (XRD) analysis showed that hematite was transformed to zero-valent iron with the increase in the roasting temperature. Scanning electron microscopy (SEM) and energy spectroscopy (EDS) analysis showed that micron-sized ZVI particles were formed in the RM-MEM, and increasing the carbon thermal reduction temperature was beneficial to the growth of zero-valent iron particles. [Display omitted] • Waste-derived iron carbon micro-electrocatalyst by carbon thermal reduction method. • Iron carbon micro-electrocatalyst shows high efficiency in the degradation of MB. • Iron carbon micro-electrocatalyst shows the potential for practical application. [ABSTRACT FROM AUTHOR]

Productions of medium-chain fatty acids (MCFAs) from waste streams via chain elongation (CE) platforms are conducive to the development of a sustainable society. Open-culture anaerobic fermentation is a promising and cost-effective technique to reclaim MCFAs from waste. Nevertheless, due to the complex microbial structure and the intertwined metabolic interactions, unwanted competing reactions including methanogenesis, excessive ethanol oxidation (EEO) and acrylate pathways always persist in the fermentation systems. Successful production of MCFAs requires the suppression of these competing reactions that could consume the substrate or byproduct used for CE process. Aiming to enhance the production of such higher-value liquids, multiple strategies have been proposed to hinder the occurrence of these undesired reactions in open-culture systems. Compared to the MCFAs productions, the roles of competitive reactions in CE processes are less well elucidated and have never been specifically reviewed before. To this end, this review first gave a general overview of CE pathways at first, followed by the introduction of the common competitive reactions that existed in the fermentation systems. Both conventional and emerging strategies to prevent competing reactions from occurring were examined in detail from the aspects of mechanisms, practicability, and the potential for improvements. The outlook for strategies with better technical feasibility was then put forward to ensure more carbon is shunted to MCFAs productions rather than wasted via competitive reactions. [Display omitted] • Overview concerning chain elongation is provided. • Competitive reactions for producing MCFAs are introduced. • Novel strategies to prevent competitive reactions from occurring are discussed. • Potential strategies with better technique feasibility are proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Food waste-derived MCFAs was synthesised predominantly at pH 5. • Chain elongators were enriched maximally at pH 5. • Chain elongation pathways were improved at pH 5. • Restricted EEO limited the ethanol loss during MCFAs production. Using food waste (FW) as a sustainable feedstock for the production of valuable medium-chain fatty acids (MCFAs) would alleviate greenhouse gas emissions while allowing the efficient recovery of carbon contained in this biowaste. The fermentation pH is a crucial factor controlling the type and yields of the MCFAs derived from FW-fed fermentation by steering the biological reactions involved. However, the mechanism shifts that occur at varying pH values are not well understood. Therefore, this study assessed the potential role of fermentation pH (i.e., 5, 7, and 10) on the carbon recovery from FW as MCFAs and the associated mechanisms. Predominantly MCFAs (5.52 g COD/L) were synthesized at pH 5 with caproate formed as the main high-value product. Abundant but a bit fewer MCFAs (1.08 g COD/L) were yielded at pH 7, in which caproate also was the prevalent MCFAs. However, no obvious MCFAs were synthesized under pH 10. The pH also drove the change of key microbial communities that served as chain elongators, which were maximally enriched at pH 5 but were scarce at pH 10. More importantly, mildly acidic pH (i.e., 5) drove less ethanol oxidization, ensuring the effective usage of electron donor for higher MCFAs yield. This study revealed how pH steers the metabolic pathways of MCFAs production from FW in open-culture anaerobic fermentation from a metagenomic viewpoint. [ABSTRACT FROM AUTHOR]

Humic substances (HS) is one of the main organic components of biowaste with high molecular weight and aromaticity. There is a growing concern that HS will hinder the recovery of biomass energy during anaerobic digestion in consideration of its recalcitrance and inhibitory effects. However, some studies have come to the exact opposite conclusion. This study for the first time comprehensively summarized the transformation mechanism, effect mechanism and inhibition mitigation strategies of HS in anaerobic digestion systems, as well as corresponding knowledge gaps, research defects and future perspectives. The content and aromaticity of HS are dynamic during anaerobic digestion followed a three-step process of release, decomposition and repolymerization, which is influenced by operation time and temperature, organic loading rate, precursor concentration and the type of substrates. In consistent with conflicting understandings of the role of HS in biomass energy recovery, HS is possible to positively or negatively affect the hydrolysis, acidification and methanogenesis processes of anaerobic digestion by acting as surfactant, adhesion agent, terminal electron acceptor, electron shuttle, organics binder or pH buffer. However, the boundary and threshold of different roles of HS are unable to be defined so far, due to the knowledge gap about the correlation between dynamic evolution of natural HS characteristics and its influencing behaviors. It is also found that HS could indirectly affect anaerobic digestion by regulating the bioavailability, biotransformation and bioactivity of exogenous pollutants (heavy metals, organohalides, microplastics, antibiotics, etc), but related knowledge is severely lacking. The existing HS inhibition mitigation strategies can be classified to passivator addition, co-digestion, pretreatment and integrate process, among which microbial electrolysis cell assisted anaerobic digestion is recommended as the most promising. [Display omitted] • Content and aromaticity of humic substances are dynamic during anaerobic digestion. • Humic substances have multiple roles in anaerobic digestion processes. • Humic substances could affect methane production by binding exogenous pollutants. • Bioelectrochemical system is promising in resource utilization of humic substances. [ABSTRACT FROM AUTHOR]

Evidence is mounting that sinomenine and peroxisome proliferator-activated receptor β/δ (PPARβ/δ) are effective against lipopolysaccharide (LPS)-induced acute lung injury (ALI) via anti-inflammatory properties. However, it is unknown whether PPARβ/δ plays a role in the protective effect of sinomenine on ALI. Here, we initially observed that preemptive administration of sinomenine markedly alleviated lung pathological changes, pulmonary edema and neutrophil infiltration, accompanied by inhibition of the expression of the pro-inflammatory cytokines Tumor necrosis factor-α (TNF-α) and Interleukin-6 (IL-6), which were largely reversed following the addition of a PPARβ/δ antagonist. Subsequently, we also noticed that sinomenine upregulated adenosine A 2A receptor expression in a PPARβ/δ-dependent manner in LPS-stimulated bone marrow-derived macrophages (BMDMs). Further investigation indicated that PPARβ/δ directly bound to the functional peroxisome proliferator responsive element (PPRE) in the adenosine A 2A receptor gene promoter region to enhance the expression of the adenosine A 2A receptor. Sinomenine was identified as a PPARβ/δ agonist. It could bind with PPARβ/δ, and promote the nuclear translocation and transcriptional activity of PPARβ/δ. In addition, combined treatment with sinomenine and an adenosine A 2A receptor agonist exhibited synergistic effects and better protective roles than their single use against ALI. Taken together, our results reveal that sinomenine exerts advantageous effects on ALI by activating of PPARβ/δ, with the subsequent upregulation of adenosine A 2A receptor expression, and provide a novel and potential therapeutic application for ALI. [Display omitted] • SIN improves ALI effectively by inhibiting excessive inflammation in vivo and in vitro. • The protection of SIN may be mediated by the activation of PPARβ/δ-adenosine A 2A receptor pathway. • This study provided a theoretical basis for the clinical application of SIN. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (H 2 S) produced by biofilms and sediments in sewer systems causes severe odor and corrosion problems, resulting in billions of dollars loss annually in the world. Meanwhile, methane (CH 4) production by anaerobic process in sewers may incur sewer explosion and greenhouse gas emission. Among all current sewer management measures, iron compounds have been widely used due to their effective impacts, non-toxicity, and relatively low cost. Owing to unique bio-chemical properties, the Fe (Ⅱ)-Fe (Ⅲ) iron cycle is also involved with the conversion of C, N, P and some other bioprocesses in sewer systems. In this review, the possible redox reactions in sewer systems related to bio-chemical iron cycle are comprehensively summarized, including sulfate oxidation, organic carbon oxidation, anaerobic ammonium oxidation and denitrification. Afterwards, the effects of iron compounds addition in sewer systems on nitrogen, phosphorus and organic pollutants removal are reviewed. Critical perspectives regarding future directions of iron assisted sewer management have been proposed to guide further research. This review is expected to provide instructive insights into the function of bio-chemical iron cycle in sewer systems. [Display omitted] • The mechanism of bio-chemical iron cycle in sewer systems is clarified. • The iron cycle inhibits H 2 S and CH 4 production and emissions. • Iron addition in sewers enhances the removal of C, N, and P. • Ferric ions improve the key sludge properties in sewer systems. [ABSTRACT FROM AUTHOR]

The dense surface passivation layer on zero-valent iron (ZVI) restricts its efficiency for water decontamination, causing a poor economy and waste of resources. Herein, we found that the ZVI on Fe-Mn biochar could afford a high electron-donating efficiency for the Cr(VI) reduction and immobilization. Over 78.0% of Fe in the Fe-Mn biochar was used for the Cr(VI) reduction and immobilization, i.e. , 56.2 − 161.7 times higher than the commercial ZVI (0.5%) and modified ZVI (0.9 −1.3%), indicating that the unique ZVI species in Fe-Mn biochar offered an outstanding Fe utilization efficiency. We proposed that oxygen atoms in the FeO in the FeMnO 2 precursor were removed during pyrolysis with biochar while the MnO skeleton was preserved, forming the embedded ZVI clusters within Fe-Mn oxide. The unique structure inhibited the formation of the Fe-Cr complex on Fe(0), which would facilitate the electron transfer between core Fe(0) and Cr(VI). Moreover, the surface FeMnO 2 inhibited the diffusion of Fe and facilitated its affinity with pollutants, thus supporting higher efficiency for pollutant immobilization. The preserved performance of Fe-Mn biochar was proved in industrial wastewater and after long-term oxidation process, and the economic benefit was evaluated. This work provides a new approach for developing active ZVI-based materials with high Fe utilization efficiency and economics for water pollution control. [Display omitted] • Over 78.0% of Fe in the Fe-Mn biochar can be used for Cr(VI) immobilization in wastewater. • Fe utilization efficiency of Fe-Mn biochar is up to 161.6 times higher than zero-valent iron (ZVI). • Fe-Mn biochar sustains its high efficiency even after interactions with impurities or oxidants. • Embedded ZVI clusters are formed by the reduction of FeMnO 2 during pyrolysis with biochar. • The unique iron species, embedded ZVI clusters, are vital to outstanding utilization efficiency. [ABSTRACT FROM AUTHOR]

[Display omitted] • The recyclable composite of CoFe-LDH with NF for PMS activation. • Complete MMH removal can be achieved with TOC removal efficiency of 80%. • 1O 2 species and electron transfer pathways were dominant for MMH decomposition. • DFT and XPS analysis elucidated momentous active species of Co and Ni in catalysis. • The sustainability of Co/Fe-LDH/NF was verified in terms of stability, reusability and metal leaching. The growing application of rocket propellants (e.g., monomethylhydrazine (MMH)) leads to awful water pollution, and thus it is urgent to develop efficient remediation methods to remove it from wastewater. Although persulfate-based catalytic technologies are promising for refractory organic compounds decomposition, the undesired aggregations, high cost and troublesome separation of powder catalysts still limit their wide-applications. To address these issues, we prepared Co-Fe layered double hydroxides (CoFe-LDH)/Ni foam (NF) composite as a recyclable peroxymonosulfate (PMS) activator to decontaminate MMH with high robustness to the high-strength co-existing pollutants within a wide pH range. The interfacial synergism between CoFe-LDH and NF could promote the charge transfer in the catalysis. DFT and XPS analysis elucidated the introduction of Ni and Co greatly facilitate charge transfer from LDH/NF to PMS. This work offers profound insights propellant-containing wastewater via non-radical (1O 2 and electron transfer) pathway in the presence of PMS with reclamation of cost-effective heterogeneous catalysts. [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]

Graphical abstract Highlights • Sophorolipid enhanced the SCFA production from anaerobic fermentation of WAS. • Sophorolipid facilitated the WAS solubilization. • Sophorolipid enhanced release of biodegradable organics. • Inhibition of methanogens by sophorolipid led to accumulation of SCFA. • Sophorolipid increased the abundance of hydrolytic microbes and SCFA producers. Abstract It was found in this study that the presence of sophorolipid (SL) enhanced the production of short-chain fatty acid (SCFA) from anaerobic fermentation of waste activated sludge (WAS). Experimental results showed that with an increase of SL addition from 0 to 0.1 g/g TSS, the maximal SCFA yield increased from 50.5 ± 4.9 to 246.2 ± 7.5 mg COD/g VSS. The presence of SL reduced the surface tension between hydrophobic organics and fermentation liquid, which thereby accelerated the disintegration of WAS and improved the biodegradability of the released organics. SL promoted the carbon/nitrogen ratio of the fermentation system, enhancing the conversion of proteins in WAS. Moreover, SL suppressed severely the activities of methanogens, probably due to the drop of pH caused by SL addition. Amplicon sequencing analyses revealed that SL increased the abundance of hydrolytic microbes such as Bacteroides sp. and Macellibacteroides sp., and SCFA producers (e.g., Acinetobacter sp.). [ABSTRACT FROM AUTHOR]

Programmed death-1 (PD-1), a key immune checkpoint molecule, has been developed as an oncotherapy target for various carcinomas. However, treatment with anti-PD-1 elicited only a minimal effect in pancreatic ductal adenocarcinoma (PDAC). Subsequent studies revealed the existence of a subset of PD-1+ T cells coexpressing CD38 and CD101, representing a fixed dysfunctional subpopulation that are not able to be rescued by anti-PD-1 immunotherapy. However, whether this subpopulation of PD-1 expressing CD8+ T cells could be useful in predicting PDAC stage or prognosing survival is unknown. In this study, we used flow cytometry and immunofluorescence assay to analyze the expression of CD38 and CD101 in 183 clinical PDAC samples, including 84 of peripheral blood and 99 of surgical tissues. High coexpression of CD38/CD101 on peripheral PD-1+CD8+ T cells or tumor-infiltrating lymphocytes (TILs) was found to be most significantly correlated with Tumor/Node/Metastasis (T/N/M) classification and clinical stage, in contrast PD-1+CD8+ T cells could not correlate with T classification. CD38/CD101 co-repression on TILs also correlated with the poor survival in these PDAC patient samples. Our data suggest that CD38/CD101 might represent a more helpful biomarker than PD-1 alone for diagnosis and prognosis of PDAC. [ABSTRACT FROM AUTHOR]

• The combination of heat pretreatment with FA promoted hydrogen yield from WAS. • The accumulative hydrogen yield was in the order of blank < heat < FA < heat + FA. • The combination of heat pretreatment with FA accelerated WAS disintegration. • The combined heat pretreatment with FA severely inhibited hydrogen consumers. Controlling free ammonia in an anaerobic fermenter at pertinent levels is reported recently to be an economically attractive and practically feasible approach to enhance hydrogen yield from waste activated sludge (WAS). This paper reports a new technology for WAS dark fermentation, i.e., using heat pretreatment (70 °C for 60 min) to assist free ammonia for further improving hydrogen yield. The experimental results showed that the accumulative hydrogen production from combined reactors was promoted from 12.3 to 19.2 mL/g VSS (volatile suspended solids), the maximum of which was 1.8, 2.7, and 7.1 times of that from sole free ammonia (131.9 mg NH 3 -N/L), sole heat, and blank reactors, respectively. Mechanism explorations showed that the combination strategy significantly enhanced WAS disintegration, providing more substrates for hydrogen production. Moreover, the combination suppressed activities of all microbes associated with anaerobic fermentation, but its inhibition to hydrogen consumers was much severer than that to other microbes. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Pretreatment of polyacrylamide-flocculated WAS (PF-WAS) was conducted. • Hydrolysis rate of PF-WAS was improved through thermal-alkaline pretreatment (TAP) • Biochemical methane potential of PF-WAS was improved through TAP. • Optimal TAP for methane yield of PF-WAS was 75 °C and pH 11.0 for 17.5 h. • Optimal TAP improved PAM's degradation and avoided acrylamide's accumulation. Abstract Deterioration of anaerobic digestion can occur with the presence of polyacrylamide (PAM) in waste activated sludge, and little information on mitigating this deterioration is currently available. In this study, simultaneous mitigation of PAM negative effects and improvement of methane production was accomplished by thermal-alkaline pretreatment. Under the optimized pretreatment conditions (i.e., 75 °C, pH 11.0 for 17.5 h), the biochemical methane potential of PAM-flocculated sludge increased from 100.5 to 210.8 mL/g VS and the hydrolysis rate increased from 0.122 to 0.187 d−1. Mechanism investigations revealed that the pretreatment not only broke the large firm floccules, improved the degradation of PAM, but also facilitated the release of biodegradable organics from sludge, which thereby provided better growth environment and enough nutrients to anaerobic microbes for methane production. The activities of key enzymes responsible for methane production and PAM degradation were greatly improved in pretreated reactor, with the accumulation of acrylamide being avoided. [ABSTRACT FROM AUTHOR]

Abstract Microplastics have aroused increasing concern as they pose threats to aquatic species as well as human beings. They do not only contribute to accumulation of plastics in the environment, but due to absorption they can also contribute to spreading of micropollutants in the environment. Studies indicated that wastewater treatment plants (WWTPs) play an important role in releasing microplastics to the environment. Therefore, effective detection of the microplastics and understanding their occurrence and fate in WWTPs are of great importance towards microplastics control. In this review, the up-to-date status on the detection, occurrence and removal of microplastics in WWTPs are comprehensively reviewed. Specifically, the different techniques used for collecting microplastics from both wastewater and sewage sludge, and their pretreatment and characterization methods are reviewed and analyzed. The key aspects regarding microplastics occurrence in WWTPs, such as concentrations, total discharges, materials, shapes and sizes are summarized and compared. Microplastics removal in different treatment stages and their retention in sewage sludge are explored. The development of potential microplastics-targeted treatment technologies is also presented. Although previous researches in microplastics have undoubtedly improved our level of understanding, it is clear that much remains to be learned about microplastics in WWTPs, as many unanswered questions and thereby concerns still remain; some of these important future research areas are outlined. The key challenges appear to be to harmonize detection methods as well as microplastics mitigation from wastewater and sewage sludge. Graphical abstract Image 1 Highlights • The detection, occurrence and behavior of microplastics in WWTPs are reviewed. • The collection, pretreatment and characterization of microplastics are analyzed. • The concentrations, materials and properties of microplastics are summarized. • The microplastics removal in WWTPs and retention in sewage sludge are explored. [ABSTRACT FROM AUTHOR]

Circular RNAs (circRNAs) are a large class of noncoding RNAs that have potential regulatory roles in disease pathogenesis and progression. Recently, circRNAs have been found to be expressed in hepatocellular carcinoma (HCC) tissues and involved in the development and metastasis of HCC. However, the significance of circRNAs in peripheral blood mononuclear cells (PBMCs) of HCC patients remains unclear. In this study, RNA sequencing analysis was performed to identify circRNAs from four HCC patients and three healthy controls to determine the expression pattern of circRNAs in the PBMCs and the circRNAs' molecular regulatory networks in HCC pathogenesis. A total of 58 circRNAs were found to be significantly changed (≥2 or ≤0.5‐fold) in the PBMCs of HCC patients compared with those of the healthy cases. Six random representative circRNAs (three up‐ and three down‐regulated) were further validated by real‐time RT‐PCR in 72 samples of PBMCs from HCC patients and 30 control subjects. Chi‐square test indicated that one of the up‐regulated circRNA candidates—circ_0000798—was correlated with clinical variables. Highly expressed circ_0000798 was associated with poor overall survival of HCC patients. Receiver operating characteristic curve analysis further revealed that circ_0000798 was discriminating HCC patients from healthy controls. Finally, the predicted competing endogenous RNA network of circ_0000798 showed that it might act as a "sponge" of target microRNAs, that would subsequently regulate the expression of target genes in PBMCs. In summary, this is the first study to comprehensively identify dysregulated circRNAs in PBMCs of HCC patients, and its findings suggest that dysregulated circ_0000798 in PBMCs has potential as a convenient biomarker for diagnosing or prognosticating HCC. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A model was developed to describe SeO 4 2− and NO 3 − reduction in H 2 -based MBfR. • A high influent SeO 4 2−/NO 3 − ratio and a thick biofilm thickness favored Se removal. • Moderate H 2 supply avoided SeRB suppression whilst minimizing H 2 wastage. • Two-stage MBfR had a slightly better removal performance than single-stage MBfR. Abstract A biofilm model was developed to describe the simultaneous NO 3 − and SeO 4 2− reduction in a H 2 -based membrane biofilm reactor (MBfR). Model calibration and validation was conducted using the experimental data of a reported H 2 -based MBfR. With a good level of identifiability, the SeO 4 2− affinity constant and the SeO 3 2− affinity constant were estimated at 9.80 ± 0.51 g Se m−3 and 1.83 ± 0.38 g Se m−3, respectively. The model was then applied to evaluate the effects of key operating conditions on the single-stage H 2 -based MBfR and the role of reactor configuration through comparing two-stage to single-stage MBfR systems. The results showed that (i) high SeO 4 2− or low NO 3 − concentration in the influent favored the growth of selenate-reducing bacteria (SeRB) and therefore benefited the Se removal, (ii) the influent dissolved oxygen slightly inhibited the Se removal through enhancing the aerobic microbial respiration on H 2 , (iii) the H 2 supply should be controlled at a proper level to avoid SeRB suppression and H 2 wastage, (iv) thin biofilm should be avoided to ensure a protected niche for SeRB and therefore a promising Se removal, and (v) the two-stage MBfR configuration offered relatively higher efficiency in removing Se and NO 3 − simultaneously under the same loading condition. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Calcium peroxide affected hydrogen production in fermentation system. • Calcium peroxide facilitated solubilization and release of biodegradable organics. • Calcium peroxide inhibited methanogenesis process. • Contributions of ingredients were in the order of alkali > O 2 − > OH. Abstract Calcium peroxide (CaO 2), one of versatile and harmless inorganic peroxy compounds, has been recently used as a highly effective oxidant to degrade pollutants in sludge and a method to achieve sludge resource utilization. However, its impact on hydrogen production has never been studied before. This investigation therefore aims to fill this knowledge gap. Results indicated that with CaO 2 increased from 0.05 to 0.25 g/g VSS (volatile suspended solids), the maximum hydrogen yield increased from 0.77 to 10.55 mL/g VSS. The mechanism studies revealed that CaO 2 accelerated the breakage and death of sludge cells. Excitation emission matrix (EEM) analyses further indicated that CaO 2 increased the biodegradability of the released substances, which could provide more biodegradable organics for the following reactions. Although CaO 2 caused inhibitions to some extents to all the tested microbes, its inhibition to hydrogen consumers was much severer than that to hydrolytic microbes and hydrogen producers. The enzyme analyses also demonstrated that the suppression of calcium peroxide to the activities of enzymes related to hydrogen consumption process was much severer than that to the activities of the activities of enzymes related to hydrogen production process. Further investigations exhibited that alkali, O 2 − and OH radicals, were the major intermediate products of CaO 2 decomposition. All of them were verified to contribute the increased hydrogen production, and their contributions were in the order of alkali > O 2 − > OH. This is the first work demonstrating that CaO 2 can enhance hydrogen production from WAS. The findings reported in our paper not only expand the application field of CaO 2 but also deepen the understanding of the CaO 2 -involved sludge fermentation process. [ABSTRACT FROM AUTHOR]

Abstract The wide application of graphene oxide nanoparticles inevitably leads to their discharge into wastewater treatment plants and combination with the activated sludge. However, to date, it is largely unknown if the nano-graphene oxide (NGO) has potential impacts on the anaerobic digestion of waste activated sludge (WAS). Therefore, this work aims to fill the knowledge gap through comprehensively investigating the effects of NGO on carbon transformation and methane production in the anaerobic digestion of WAS. Biochemical methane potential tests demonstrated the methane production dropped with increasing NGO additions, the cumulative methane production decreasing by 7.6% and 12.6% at the NGO dosing rates of 0.054 mg/mg-VS and 0.108 mg/mg-VS, respectively. Model-based analysis indicated NGO significantly reduced biochemical methane potential, with the highest biochemical methane potential decrease being approximately 10% at the highest NGO dosing rate. Further experimental analysis suggested that the decreased methane production was firstly related to a decrease in soluble organic substrates availability during the process of sludge disintegration, potentially attributing to the strong absorption of organic substrates by NGO. Secondly, NGO significantly inhibited the methanogenesis by negatively affecting the corresponding enzyme activity (i.e. coenzyme F420), which could also resulted in a decreased methane production. Graphical abstract Unlabelled Image Highlights • The methane production from WAS anaerobic digestion deteriorated with NGO exposure. • NGO decreased the release of soluble organics during WAS disintegration due to adsorption. • NGO negatively affected the methanogenesis through inhibiting coenzyme F420 activities. • Hydrolysis and acidogensis were not affected by NGO during WAS anaerobic digestion. [ABSTRACT FROM AUTHOR]

Background/Aims: Cancer stem cells (CSCs) are largely responsible for tumor relapse and metastatic behavior. Doublecortin-like kinase 1 (DCLK1) was recently reported to be a biomarker for gastrointestinal CSCs and involved in the epithelial-mesenchymal transition (EMT) and tumor progression. B cell-specific Moloney murine leukemia virus insertion site 1 (Bmi-1) is a crucial regulator of CSC self-renewal, malignant transformation and EMT, and a previous study from our group showed that Bmi-1 is upregulated in pancreatic cancer progression and participates in EMT. However, it remains unclear whether DCLK1 is involved in pancreatic cancer or whether DCLK1 is associated with the altered level of Bmi-1 expression. Methods: The correlation of DCLK1 expression and clinical features of pancreatic cancer was analyzed in 210 paraffin-embedded archived pancreatic cancer specimens by immunohistochemical analysis. The biological effects of DCLK1 siRNA on cells were investigated by examining cell proliferation using a cell counting kit and cell colony assays, cell migration by wound healing assay and cell invasion by Transwell invasion assay. We further investigated the effect of therapeutic siRNA targeting DCLK1 on pancreatic cancer cell growth in vivo. Moreover, the molecular mechanism by which DCLK1 upregulates Bmi-1 expression was explored using real-time PCR, western blotting and Co-immunoprecipitation assay. Results: DCLK1 is overexpressed in pancreatic cancer and is related to metastasis and prognosis. Knockdown of DCLK1 markedly suppressed cell growth in vitro and in vivo and also inhibited the migration and invasion of pancreatic cancer cells. Furthermore, we found that DCLK1 silencing could inhibit EMT in cancer cells via downregulation of Bmi-1 and the mesenchymal markers Snail and Vimentin and upregulation of the epithelial marker E-cadherin. Moreover, high DCLK1 expression in human pancreatic cancer samples was associated with a mesenchymal phenotype and increased cell proliferation. Further co-immunoprecipitation indicated that DCLK1 did not interact with Bmi-1 directly. Conclusion: Our data suggest that upregulation of DCLK1 may contribute to pancreatic cancer metastasis and poor prognosis by increasing Bmi-1 expression indirectly. The findings indicate that inhibiting DCLK1 expression might be a novel strategy for pancreatic cancer therapy. [ABSTRACT FROM AUTHOR]

Abstract Simultaneous sludge fermentation and nitrite removal is an effective approach to enhance nutrient removal from low carbon-wastewater. It was found in this work that the presence of nitrite largely promoted hydrogen production from acidic fermentation of waste activated sludge (WAS). The results showed that with an increase of nitrite from 0 to 250 mg/L, the maximal hydrogen yield increased from 8.5 to 15.0 mL/g VSS at pH 5.5 fermentation and 8.1–13.0 mL/g VSS at pH 6 fermentation. However, the maximal hydrogen yield from WAS fermentation at pH 8 remained almost constant (2.9–3.7 mL/g VSS) when nitrite was in the range of 0–250 mg/L. Further analyses revealed that free nitrous acid (FNA) rather than nitrite was the major contributor to the promotion of hydrogen yield. The mechanism investigations showed that FNA not only accelerated the disruption of sludge cells but also promoted the biodegradability of organics released, thereby provided more biodegradable substrates for subsequent hydrogen production. Although FNA inhibited activities of all microbes involved in the anaerobic fermentation, its inhibitions to hydrogen consumers were much severer than those to hydrolytic microorganisms and hydrogen producers. Further investigations with microbial community showed that FNA increased the abundances of hydrogen producers (e.g., Citrobacter sp.) and denitrifiers (e.g., Dechloromonas sp.), but reduced the abundances of hydrogen consumers (e.g., Clostridium_aceticum). This work demonstrated for the first time that FNA in WAS fermentation systems enhanced hydrogen production. The findings obtained expand the application field of FNA and may provide supports for sustainable operation of wastewater treatment plants. Graphical abstract Image 1 Highlights • Nitrate addition promoted hydrogen production from anaerobic fermentation of sludge. • Free nitrous acid (FNA) rather than nitrite was the major contributor to the promotion of hydrogen yield. • FNA not only accelerated the disruption of sludge cells but also promoted the biodegradability of organics released. • FNA increased the abundances of hydrogen producers and denitrifiers, but reduced the abundances of hydrogen consumers. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • CFHP was applied to improve methane production from WAS for the first time. • Hydrolysis rate of WAS are improved through CFHP. • Biochemical methane potential of WAS are improved through CFHP. • CFHP is an attractive technology for the application in real-world situations. Abstract Anaerobic digestion of waste activated sludge (WAS) is often limited by low hydrolysis efficiencies and poor methane potentials. This work presents a novel pretreatment technology for WAS anaerobic digestion, i.e., combining free ammonia with heat pretreatment (CFHP). Experimental results showed that compared with control, solo free ammonia (135.4 mg NH 3 -N/L) and solo heat (70 °C) pretreatment, the combined free ammonia and heat (135.4 mg NH 3 -N/L with 70 °C) obtained 52.2%, 25.5% and 30.2% faster in hydrolysis rate and 25.2%, 17.9% and 16.5% higher in biochemical methane potential, respectively. Mechanism investigations showed that the combined pretreatment not only largely facilitated the disintegration of WAS but also increased the proportion of biodegradable organic matters, thereby providing better contract between biodegradable organics and the anaerobic microbes for methane production. Considering its effectiveness and renewability, the combined pretreatment is an attractive technology for the application in real-world situations. [ABSTRACT FROM AUTHOR]

This study proposed a novel zero valent iron (ZVI) technology to enhance anaerobic methane production from primary sludge in the anaerobic digester and to improve the dewaterability of digested sludge for the first time. Compared to the control test without ZVI, the anaerobic digester with ZVI at all levels (1, 4 and 20 g/L) played a driving role in anaerobic methane production from primary sludge. The maximal biochemical methane production of 439 ± 5 L CH 4 /kg VS was achieved at ZVI of 4 g/L, while only 345 ± 2 L CH 4 /kg VS (volatile solids) was produced in the case of no-ZVI dosage, representing a relative increase of 26.9 ± 0.1%. It was also found that ZVI addition would produce an anaerobically digested sludge with a better dewaterability, as indicated by the decrease of the normalized capillary suction time from 100 to 63 ∼ 89 s, respectively. Model based analysis revealed that the enhanced methane production from primary sludge was due to an increase in both hydrolysis rate and biochemical methane potential of primary sludge. Economic analysis demonstrated that ZVI technology was economically favorable. [ABSTRACT FROM AUTHOR]

Complete nitrogen removal has recently been demonstrated by integrating anaerobic ammonium oxidation (anammox) and denitrifying anaerobic methane oxidation (DAMO) processes. In this work, the effect of methane partial pressure on the performance of a membrane biofilm reactor (MBfR) consisting of DAMO and anammox microorganisms was evaluated. The activities of DAMO archaea and DAMO bacteria in the biofilm increased significantly with increased methane partial pressure, from 367 ± 9 and 58 ± 22 mg-N L −1 d −1 to 580 ± 12 and 222 ± 22 mg-N L −1 d −1 , respectively, while the activity of anammox bacteria only increased slightly, when the methane partial pressure was elevated from 0.24 to 1.39 atm in the short-term batch tests. The results were supported by a long-term (seven weeks) continuous test, when the methane partial pressure was dropped from 1.39 to 0.78 atm. The methane utilization efficiency was always above 96% during both short-term and long-term tests. Taken together, nitrogen removal rate (especially the nitrate reduction rate by DAMO archaea) and methane utilization efficiency could be maintained at high levels in a broad range of methane partial pressure (0.24–1.39 atm in this study). In addition, a previously established DAMO/anammox biofilm model was used to analyze the experimental data. The observed impacts of methane partial pressure on biofilm activity were well explained by the modeling results. These results suggest that methane partial pressure can potentially be used as a manipulated variable to control reaction rates, ultimately to maintain high nitrogen removal efficiency, according to nitrogen loading rate. [ABSTRACT FROM AUTHOR]

Autophagy and mitophagy have been shown to occur in spinal cord injury (SCI). Bcl-2/E1B-19KD-interacting protein 3 (BNIP3) and its homologue, NIX, have been implicated in the regulation of mitophagy. The aim of this work was to characterize the mechanisms and role of BNIP3 in SCI-associated mitophagy. Our data showed that BNIP3, targeted to mitochondria, interacted with microtubule-associated protein 1A/1B-light chain 3 (LC3), which is targeted to autophagosomes, thus forming a mitochondria-BNIP3-LC3-autophagosome complex and resulting in mitophagy. Downregulation of BNIP3 by RNA interference strengthened the mitochondrial function and decreased cell death in spinal cord neurons under hypoxia. Particularly, BNIP3 knockdown significantly improved neurological recovery and the number of neuronal nuclei–positive cells post-SCI in rats. The present study demonstrated that BNIP3 interacts with LC3 to induce mitophagy, whereas its inhibition provided protective neuronal effects in SCI rat models both in vivo and in vitro. [ABSTRACT FROM AUTHOR]

Previous studies reported that free ammonia (FA) pretreatment could improve methane production from anaerobic digestion of waste activated sludge (WAS) effectively. However, details of how FA pretreatment improves methane production are poorly understood. This study therefore aims to reveal the underlying mechanisms of FA pretreatment affecting anaerobic digestion of WAS through a series of batch tests using either real sludge or synthetic media as the digestion substrates at different pH values. At pH 8.5 level, with an increase of FA level from 18.5 to 92.5 mg/L (i.e., NH+ 4-N: 100–500 mg/L; pH 8.5) the maximum methane yield varied between 194.0 ± 3.9 and 196.9 ± 7.7 mL/g of VSS (25 °C, 1 atm). At pH 9.5 or 10 level, however, with an increase of initial FA level from 103.2 to 516.2 mg/L, the maximal methane yield increased linearly. The mechanism studies revealed that FA pretreatment at high levels not only accelerated the disintegration of WAS but also enhanced the biodegradability of WAS. Although pH in the digesters was adjusted to 7.0 ± 0.1, the high levels of NH+ 4-N added or released led to substantial levels of residual FA ranging from 4.4 to 11.6 mg/L. It was found that this level of FA inhibited homoacetogenesis and methanogenesis significantly, though hydrolysis, acidogenesis, and acetogenesis processes were unaffected largely. Further analyses showed that the inhibition constant of FA to substrate degradation was in the sequence of dextran > glucose > hydrogen > acetate, indicating the methanogenesis process was more sensitive to FA. [ABSTRACT FROM AUTHOR]

[Display omitted] • Manganese ore addition significantly increased PAHs removal in CW. • Microbial degradation was the dominant removal mechanism to remove PAHs in CW. • Manganese ore enhanced electron transfer capacity in CW by altered EPS and Mn cycle. • Manganese ore changed microbial community and microbial metabolic expression in CW. • Root length and microbial diversity were two driven factors affecting PAHs removal. Substrates are vital to efficiently remove polycyclic aromatic hydrocarbons (PAHs) in constructed wetlands (CW). However, the critical role of the substrate in the system is still not fully understood due to the unclear PAHs removal mechanism and particularly the main driving factor affecting PAHs removal. In this study, four vertical-flow CWs with different typical substrate types (A: quartz sand, B: quartz sand + granular activated carbon, C: quartz sand + ceramsite, and D: quartz sand + manganese ore) were established to investigate the treatment performance and mechanism of CW systems. Satisfactory and stabilized PAHs removal was achieved in CW-D during the operation period of 120 days, which significantly increased the removal of PAHs by 23.80%–31.18% compared with control group. Microbial degradation was revealed to dominate PAHs removal in CWs, and the enhanced proportion of microbial degradation (21.12%-35.43%) in CW-D led to the higher PAHs removal compared with other CWs. Further analysis showed that altered extracellular polymeric substances and Mn cycle improved the electron transfer capacity, and strengthened the interaction between plants and microorganisms in CW-D. Microbial analysis showed that the abundance of key PAH-degrading microorganisms and microbial metabolic gene expression were enhanced in CW-D, which supported the increased microbial degradation of PAHs. Additionally, root length and microbial diversity were two driving factors affecting PAHs removal rather than specific surface area based on the structural equation modeling analysis. This study provides comprehensive insights into the key role of suitable substrates for PAHs removal as well as the related mechanism and driving factors of PAHs removal in CWs. [ABSTRACT FROM AUTHOR]

In recent years utilizing nanoparticles in black paint (nano-paint) of solar desalination absorbers has become a topic growing interest. However, in most of studies, only the effect of using different types of nanoparticles brought into the spotlight, while in those limited studies that discussed on optimum concentration of nanoparticles, the results were controversial and not conclusive. Herein, an experimental study to find the optimum concentration of nanoparticles (silver, 1–5%) in solar absorbers in summer, spring and autumn with/without reflectors was conducted. To find the optimum concentration, performance of the systems from different viewpoints including energetic, exergetic, economic, productivity, exergoeconomic, energy-matrices, and environmental (amount of CO 2 /SO 2 /NO emission/reduction) analysis for each season and thorough its lifetime was examined thoroughly. Ascribe the highly variable of parameters; two Matlab codes have been developed to precisely calculate the economic and exergoeconomic parameters for different scenarios. The results showed that increasing the nanoparticle concentration to 5% from an economic viewpoint was reasonable just in summer, while for autumn and spring, 2.5% was optimum. The same was valid for productivity and exergy analysis. Importantly, the embodied energy of nanoparticles for the first time considered in calculation to obtain more accurate results in terms of environmental analysis and energy-matrices. Finally, it was concluded that even though using 5% nanoparticle in limited cases led to better results, the 2.5% concentration with reflector was optimum for all seasons and through the lifetime. This work would be a cornerstone for future researches in the context of using nano-paint in solar absorbers. [Display omitted] • Optimum concentration of nanoparticle in solar absorber in autumn, spring and summer. • Productivity, energy, exergy, economic, environmental, exergoeconomic, energy-matrices consider as criteria assessment. • Improvements for nanoparticle at 1%–2.5% is higher than 2.5%–5% for all seasons. • Negative effect on increasing nanoparticle from 2.5% to 5% in autumn and spring observed. • Although 5% in limited cases has better results, 2.5% regarding all criteria proposed for real-world applications. [ABSTRACT FROM AUTHOR]

Earth abundant transition metal-based materials are widely served as peroxymonosulfate (PMS) activators for degradation of emerging contaminants. However, the agglomeration of catalyst particles and metal ion leaching hinder their practical applications for pollutant decomposition. In this study, a Co 3 O 4 -carbonized polyaniline composite (Co 3 O 4 /CPANI) was implemented for PMS activation. The Co 3 O 4 /CPANI + PMS system exhibited high catalytic performance toward tetracycline (TC) degradation (degradation efficiency of 92.11%, initial TC level of 20 mg/L). Moreover, the practical application potential of Co 3 O 4 /CPANI + PMS system was well verified with three antibiotics (i.e., TC, doxycycline (DOX), and ciprofloxacin (CIP)) at highest actual aquatic environmental levels (1.0 and 0.5 mg/L). In the established Co 3 O 4 /CPANI + PMS system, both radicals (•O 2 −, •OH and SO 4 •-) and non-radical (1O 2) contributed to TC degradation, and 1O 2 was the dominant reactive oxygen species (ROS). C O groups, oxygen vacancies (O VS), redox pairs of Co2+/Co3+ species, and graphitic N all served as active sites in the PMS activation process, especially, O VS were crucial for the generation of 1O 2. This study provides an efficient method for the synthesis of metal-based nanocatalysts with low nanoparticle aggregation and metal leaching which could act as a sustainable PMS activator for the remediation of TC-polluted water environment. [Display omitted] • Co 3 O 4 /CPANI + PMS exhibited excellent EC removal with TC degradation efficiency of 92.11%. • 1O 2 was dominant ROS in the catalytic degradation process. • Co 3 O 4 /CPANI + PMS effectively works with the existence of co-existing ions and organic compounds. • The sustainability of Co 3 O 4 /CPANI was verified by stability, reusability and metal leaching. • Co 3 O 4 /CPANI + PMS system exhibits great potential in practical application. [ABSTRACT FROM AUTHOR]

Pyrite is the most common metal sulfide mineral in the crust and readily weathers under natural circumstances to release H+ to acidify surrounding groundwater and soil, resulting in heavy metal ions in the surrounding environment (e.g., meadow and saline soils). Meadow and saline soils are two common, widely distributed alkaline soils and can affect pyrite weathering. Currently, the weathering behaviors of pyrite in saline and meadow soil solutions have not been systematically studied. Electrochemistry coupled with surface analysis methods were employed to study pyrite weathering behaviors in simulated saline and meadow soil solutions in this work. Experimental results suggest that saline soil and higher temperatures increase pyrite weathering rates due to the lower resistance and greater capacitance. Surface reactions and diffusion control the weathering kinetics, and the activation energies for the simulated meadow and saline soil solutions are 27.1 and 15.8 kJ mol−1, respectively. In-depth investigations reveal that pyrite is initially oxidized to Fe(OH) 3 and S0, and Fe(OH) 3 further transforms into goethite γ-FeOOH and hematite α-Fe 2 O 3 , while S0 ultimately converts into sulfate. When these iron compounds enter alkaline soils, the alkalinity of soil changes, and iron (hydr)oxides effectively reduce the bioavailability of heavy metals and benefit alkaline soils. Meanwhile, weathering of natural pyrite ores containing toxic elements (such as Cr, As, and Cd) makes these elements bioavailable and potentially degrades the surrounding environment. [Display omitted] • Pyrite weathering generates γ-FeOOH and α-Fe 2 O 3 with lesser environmental impacts. • Pyrite weathering decreases the alkalinity of alkaline soils. • Pyrite weathering prone to saline (91.87 g/m2/y) than meadow (71.18 g/m2/y) soil. • Impure pyrite releases heavy ions pollute alkaline soil. • T promotes weathering as v Meadow = - 3.37E5 /T + 1.25E3, v Saline = - 2.73E5 /T + 1.07E3. [ABSTRACT FROM AUTHOR]

• Amorphous Fe-doped NiB outperforms crystalline and undoped counterparts for UOR. • Urine electrolyzer attained 46 times higher H 2 yield than the water electrolyzer. • Crystallinity-dependent structure self-reconstruction process during UOR. • Fe regulates catalyst's electronic structure and forms bimetallic sites for UOR. Designing transition metal-based catalysts for efficient urea oxidation reaction (UOR) is important for realizing energy-saving hydrogen production via urea-rich (waste)water electrolysis. Herein, we have developed an iron-doped amorphous nickel boride electrocatalyst (aFe-NiB) for UOR. Compared with the undoped and crystalline counterparts, aFe-NiB exhibits a higher activity and the benchmark current density of 10 mA cm−2 can be attained at 1.298 V vs. reversible hydrogen electrode (RHE). Coupled with an efficient hydrogen evolution catalyst, the aFe-NiB-assisted urine electrolyzer can attain a 46 times higher H 2 production rate than the water electrolyzer at 1.50 V. Further study reveals a crystallinity-dependent structure self-reconstruction process during UOR. aFe-NiB attains complete phase evolution from boride to electroactive Fe-doped NiOOH. In addition, density functional theory calculations imply that Fe dopants can improve intrinsic catalytic activity via electronic structure regulation of the self-evolved NiOOH and forming heterogeneous bimetallic active sites for UOR. This study provides meaningful insights into the crystallinity-dependent UOR performance and effective strategies to develop efficient UOR (pre)catalysts with dual active sites. Significantly, the demonstrated direct wastewater (urine) electrolysis paves the way for net zero buildings -targeted human waste reutilization. [ABSTRACT FROM AUTHOR]

• Low-rate Fe(VI) dosing can cause the destructive effect on sewer biofilm structure. • Fe(VI) mainly reduced HS in biofilm EPS thus leading to loosed biofilm structure. • Key functional groups holding macromolecular of HS were more vulnerable to Fe(VI). • Fe(VI) enhanced microbial interaction barriers so biofilms reduced mechanical stability. • Fe(VI) enhanced inactivation effects of biocides on sewer biofilms with reduced cost. The microbial activities in sewer biofilms are recognized as a major reason for sewer pipe corrosion, malodor, and greenhouse gas emissions. However, conventional methods to control sewer biofilm activities were based on the inhibitory or biocidal effect of chemicals and often required long exposure time or high dosing rates due to the protection of sewer biofilm structure. Therefore, this study attempt to use ferrate (Fe(VI)), a green and high-valent iron, at low dosing rates to damage the sewer biofilm structure so as to enhance sewer biofilm control efficiency. The results showed the biofilm structure started to crush when the Fe(VI) dosage was 15 mg Fe(VI)/L and the damage enhanced with the increasing dosage. The determination of extracellular polymeric substances (EPS) showed that Fe(VI) treatment at 15-45 mgFe/L mainly decreased the content of humic substances (HS) in biofilm EPS. This is because the functional groups, such as C-O, -OH, and C=O, which held the large molecular structure of HS, were the primary target of Fe(VI) treatment as suggested by 2D-Fourier Transform Infrared spectra. As a result, the coiled chain of EPS maintained by HS was turned to extended and dispersed and consequently led to a loosed biofilm structure. The XDLVO analysis suggested that both the microbial interaction energy barrier and secondary energy minimum were increased after Fe(VI) treatment, suggesting that the treated biofilm was less likely to aggregate and easier to be removed by the shear stress caused by high wastewater flow. Moreover, combined Fe(VI) and free nitrous acid (FNA) dosing experiments showed for achieving 90% inactivation, the FNA dosing rate could be reduced by 90% with the exposure time decreasing by 75% at a low Fe(VI) dosing rate and the total cost was substantially decreased. These results suggested that applying low-rate Fe(VI) dosing for sewer biofilm structure destruction is expected to be an economical way to facilitate sewer biofilm control. [Display omitted] [ABSTRACT FROM AUTHOR]