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Traditional technologies such as precipitation and coagulation have been adopted for fluoride-rich and silica-rich wastewater treatment, respectively, but waste solid generation and low wastewater processing efficiency are still the looming concern. Efficient resource recovery technologies for different wastewater treatments are scarce for environment and industry sustainability. Herein, a resource capture ultrafiltration-bipolar membrane electrodialysis (RCUF-BMED) system was designed into a closed-loop process for simultaneous capture and recovery of fluoride and silica as sodium silicofluoride (Na

The separation of hardness ions such as calcium and magnesium from hard water can improve water quality, which is important but technically challenging. Nanofiltration (NF) has attracted much attention because of its efficiency, environmental friendliness and low cost. However, common NF membranes with a singly (either positively or negatively) charged layer have insufficient water softening capacity. In this work, two types of dual-layer Janus charged polyamide NF membranes composed of oppositely charged inner and outer layers were developed for the first time by sequential electrospray polymerization strategy for efficient water softening. The effect of the microstructure of the dually charged barrier layer on the separation performance of divalent salt ions was explored. Detailed mechanistic studies revealed that the microstructure of the outer layer of the barrier layer played a crucial role in the ion separation of the Janus membrane due to its control of the reverse transport of ions. Janus charged polyamide NF membrane with a loose outer layer exhibited better water softening performance (93.6% of hardness removed) compared to the singly charged NF membranes due to the simultaneous dual electrostatic effect and no ion reverse transport confinement. This Janus charged NF membrane also possessed good antifouling performance, mainly due to its negatively charged outer layers. The mechanistic insights gained in this study reveal the huge potential of microstructural design toward high-performance Janus charged NF membranes, and provide important guidance on the future development of high-efficiency water softening NF membranes.

Papermaking industry discharges large quantities of wastewater and waste gas, whose treatment is limited by extra chemicals requirements, insufficient resource recovery and high energy consumption. Herein, a chemical self-sufficiency zero liquid discharge (ZLD) system, which integrates nanofiltration, bipolar membrane electrodialysis and membrane contactor (NF-BMED-MC), is designed for the resource recovery from wastewater and waste gas. The key features of this system include: 1) recovery of NaCl from pretreated papermaking wastewater by NF, 2) HCl/NaOH generation and fresh water recovery by BMED, and 3) CO

Electrospun poly(dimethyl siloxane)/poly(methyl methacrylate) (PDMS/PMMA) membrane (EPPM) is an emerging material in membrane aromatic recovery system (MARS) for phenol separation from saline wastewater. However, its application and performance in MARS are hindered by poor mechanical property. To solve this issue, thermoplastic polyurethanes (TPU) was mixed with PDMS and PMMA to fabricate novel electrospun TPU/PDMS/PMMA membrane (ETPPM). Membrane morphologies showed that intrinsically random oriented fibers of EPPM were gradually changed into the self-bundled fiber yarns with point-bonded structure, which led to the tensile strength and elongation at break of ETPPM-3 increased 12.6 times and 89.9%, respectively after 1.5 g TPU addition. Furthermore, ETPPM-3 presented a simultaneous organophilic and hydrophobic surface with phenol static contact angle of 0° and NaCl solution static contact angle of 143.4°, indicating its potential in phenol separation from saline wastewater. After 24 h MARS operation, 498.3 mg L−1 of phenol was separated from the initial phenol saline wastewater (2.0 g L−1 phenol and 10.0 g L−1 NaCl) with a conductivity increase of 21.2 µs cm−1. As a result, 24.9% of phenol recovery and 99.86% of salt rejection were achieved with mean phenol mass transfer coefficient of 7.3 × 10−7 m s−1 and flux of 4.4 × 10−4 kg m−2 s−1.

There has been increasing concern over the mixed discharge of municipal-textile composite wastewater, which remains challenging for typical wastewater treatment plant (WWTP) using anaerobic-anoxic-oxic process (AAO). Highly-toxic aniline and antimony, typical co-contaminants in textile wastewater, usually lead to increased chemical oxygen demand (COD) in influent and deteriorated effluent quality. Amidoxime-modified polyacrylonitrile (amPAN) adsorbent was prepared and added to adsorb antimony and facilitate substrate removal. With amPAN dosage at 6.0 g L

Photovoltaic wastewater contains a large amount of thiourea that cannot be directly treated by biological methods because of its biotoxicity. In this study, a novel O3/H2O2 + BiPO4/UV synergy technique was used as a pre-treatment process to degrade thiourea. The effects of H2O2 and catalyst loading were investigated, and the transformation pathway of thiourea was predicted based on the intermediates detected by UPLC-Vion-IMS-QToF. The synergy technique degraded 89.14% thiourea within only 30 min, and complete degradation occurred after 150 min. The TOC removal of O3/H2O2 + BiPO4/UV was 1.8, 1.5, and 1.9 times that of O3/H2O2 and BiPO4/UV/H2O2 single processes and O3/H2O2 + UV process, respectively, which was due to the synergy between H2O2 residues and BiPO4. In addition, thiourea was mainly degraded by ·OH into thiourea dioxide and melamine (polymerized by other intermediates) and then further degraded into biuret and methyl carbamate by the holes of BiPO4, followed by complete mineralization into H2O and CO2. These results confirm that the O3/H2O2 + BiPO4/UV synergy technique is a promising option for the degradation of thiourea.

Amidoxime-polyacrylonitrile (APAN) nanofiber possesses advantages of adsorbing heavy metals for abundant amidoxime groups. However, it easily suffers from poor mechanical property caused by fiber contraction during amidoximation process. Inspired by high mechanical strength of reinforced concrete, we embedded stiff polylactic acid (PLA) skeletons into PAN matrix to prepare reinforced-concrete structured nanofiber sphere (APAN/PLA NFS) through solution blending. Preparation parameters including polymer concentration and PAN/PLA ratio were optimized as 4.0% and 1:1, and coarse sphere surface, numerous mesopores and large pore volume (19.3 mL/g) were endowed. Scanning electron microscope results showed restricted fiber contraction with nitrile conversion of 58.1%. APAN/PLA NFS showed robust compressive strength of 3.28 MPa with strain of 80%, and X-ray diffraction and differential scanning calorimeter analysis revealed that crystalline PLA reinforced non-crystalline PAN through molecule-level compatibility. Compared with plain APAN sphere, Sb(V) adsorption from water for APAN/PLA NFS showed better performance with superhigh capacity of 949.7 mg/g and fast rate (equilibrium time of 2 h), which was owing to abundant mesopores preserved by PLA skeletons. These findings indicated that PLA was a promising skeletal candidate which could protect APAN from fiber contraction during amidoximation process and could strongly expand adsorption capacity of APAN for heavy metals.

Extractive membrane bioreactor (EMBR) is a promising technology for phenol saline wastewater treatment. In this work, an electrospun polydimethylsiloxane/polymethyl methacrylate/multi-walled carbon nanotubes (PDMS/PMMA/MWCNTs) membrane was firstly used in EMBR. To address low phenol transmembrane mass transfer issue, effects of wastewater condition (1.3–5.5 L/h circulation rate, 1000–4000 mg/L phenol), biomass addition (without/with pre-acclimated activated sludge) and biofilm formation (50.5–120.7 μm) were investigated. Membrane characterizations confirmed that biofilms on membrane surface gradually developed under increasing phenol concentrations, with simultaneously increased thickness and extracellular polymeric substances (EPS) excretion. Results showed phenol transmembrane mass transfer rates with activated sludge and formed biofilm increased 21.6–31.7% compared to those without activated sludge. Finally, 100% removal of permeated phenol and 99.96% rejection of salt were achieved under wastewater circulation rate of 4.4 L/h with 1000–4000 mg/L phenol and 10 g/L sodium chloride. Relevant findings are of significance in promoting the EMBR application in organic-inorganic composite wastewater treatment.

PPCPs and pesticides have been documented throughout the world over the years, yet relatively little is known about the factors affecting their spatial distribution and temporal change in order to know their potential risk to the ecosystem or human health in the future. In our study, 5 PPCPs and 9 pesticides were selected to study their occurrence, impact variables and potential risk in a drinking water reservoir in Yangtze Estuary and related drinking water treatment plants (DWTPs) in China. The detection results showed the presence of PPCPs and pesticides reflected in a large part of croplands and urban and built-up land in the adjacent basin. The discrepancy of concentration among the different PPCPs and pesticides was mainly decided by their application amount or daily usage. Then, the major factors regulating the occurrence of these contaminants in the surface water were found as the living expenditure attributed to food and medicine based on a correlation analysis. Also, the PPCPs were found to negatively correlate to the effectiveness of sewage management. The detection of the PPCPs and pesticides in DWTPs indicated that, except for atrazine and simazine, the removal percentages were increased significantly in advanced DWTPs. Moreover, risk assessment estimated by a Risk Quotient and Hazard Quotient showed that while caffeine, bisphenol A, estrone and simazine were at a high-risk level in the reservoir water, all of the contaminants detected posed no risk to human health through drinking water. It's possible that atrazine could pose a high risk to the ecosystem while simazine could pose a risk to human health in the future considering the increasing expenditure attributed to food.

Membrane bioreactor with non-woven fabric membranes (NWMBR) is developing into a suitable method for anaerobic ammonium oxidation (anammox). As a carrier, non-woven fabric membrane divided total biomass into biofilm and suspended flocs gradually. Total nitrogen removal efficiency was maintained around 82.6% under nitrogen loading rate of 567.4mgN/L/d after 260days operation. Second-order substrate removal and Stover-Kincannon models were successfully used to simulate the nitrogen removal performance in NWMBR. High-throughput sequence was employed to elucidate the underlying microbial community dynamics. Candidatus Brocadia, Kuenenia, Jettenia were detected to affirm the dominant status of anammox microorganisms and 98.2% of anammox microorganisms distributed in biofilm. In addition, abundances of functional genes (hzs, nirK) in biofilm and suspended flocs were assessed by quantitative PCR to further investigate the coexistence of anammox and other microorganisms. Potential nitrogen removal pathways were established according to relevant nitrogen removal performance and microbial community.

High-performance thin film composite polyamide (TFC-PA) membranes with controllable structure and transport properties are of great significance. However, TFC-PA membranes prepared by interfacial polymerization are far from ideal due to their quick and uncontrollable reaction process. In this study, we reported a novel strategy to fabricate TFC-PA membranes via an electrospray interface-less polymerization (EILP) technique with a miscible solvent system. The miscible solvent system facilitated both the stable and fine spraying of monomer solutions and the efficient polymerization of monomers, and thus resulting in the formation of a smooth and defect-free PA skin layer. Moreover, the crosslinking degree and thickness of the EILP membrane skin layer could be controlled easily by regulating the concentration and dose of sprayed monomers. Attenuated total reflectance-Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, zeta potential and mean effective pore size were employed to characterize the EILP membrane and clarify the separation mechanism. The optimum EILP membrane showed excellent filtration performance with a high water flux of up to 17.7 L m−2 h−1 bar−1, high salt rejection (98.2% of Na2SO4) and complete dye rejection for Congo red. This study provides new insights into the understanding of electrospray procedures and enlightens the design and manufacture of advanced membrane materials through electrospray.

The traditional adsorbents for antimonate (Sb(V)) in industrial effluent suffered from poor adsorption capacity due to the lack of pores or adsorption sites. Three-dimensional (3D) amidoxime-polyacrylonitrile sphere (APANS) with hierarchical pores and abundant amidoxime groups was fabricated via nanoscale thermally induced phase separation (TIPS). The effects of fabrication parameters including diluent type, PAN concentration and amidoximation time on pore structure were studied with scanning electron microscopy (SEM), mercury intrusion instrument (MIP), fourier transform infrared spectrophotometer (FT-IR) and X-ray photoelectron spectroscopy (XPS). Results showed that APANS fabricated from 2% PAN/DMSO solution and amidoximated for 20 min had coarse surface, numerous mesopores, high porosity (88.5%) and large pore volume (20.5 mL/g). The pore formation mechanism revealed that the hierarchical pores were derived from multiscale DMSO crystals shaped by TIPS. Adsorption kinetics results showed that kinetics data were well fitted by pseudo-second-order model (R2 > 0.99) and the mesopores accelerated the adsorption (equilibrium time of 4 h) due to enormous surface excess and group exposure. Adsorption isotherm could be modeled by Freundlich (R2 > 0.99) and maximum adsorption capacity was 683.6 mg/g. The adsorption thermodynamics was also investigated, indicating the spontaneous and exothermic adsorption process. APANS exhibited excellent selectivity towards common anions (Cl−, SO42−, NO3− and PO43−) and reliable reusability (preserving 80% capacity after five cycles). This adsorbent provided a clean and sustainable strategy for Sb(V) removal from aqueous environment by superhigh capacity, fast rate and reliable reusability.

The major challenges for electrospun membranes used in direct contact membrane distillation (DCMD) process are insufficient pore wetting resistance related with hydrophobicity and pore structure of membrane surface. A novel super-hydrophobization method containing first coating TiO2 nanoparticles on membrane surface by the low temperature hydrothermal process and then the TiO2 coated membrane being fluorosilanized with low surface energy material of 1H, 1H, 2H, 2H-perfluorododecyl trichlorosilane (FTCS) was employed to modify the virgin polyvinylidene fluoride electrospun nanofiber membrane (PVDF ENM). Results showed that this TiO2-FTCS modified membrane possessed high hydrophobicity (157.1°), high mean roughness (4.63 μm), considerable wetting resistance (158 kPa), well-distributed pore size (0.81 μm), reasonable surface porosity (57%) and modest membrane thickness (55 μm). These combined properties made the modified PVDF ENM an attractive candidate for DCMD. High flux and stable desalination performances were achieved during short-term DCMD process (73.4 LMH permeate flux, 99.99% salt rejection) using 3.5 wt% NaCl solution. Long-term DCMD process with actual reverse osmosis brine as feed solution also showed high performance (40.5 LMH, 99.98%). These results exceeded those of commercial PVDF membrane and unmodified PVDF ENM significantly, suggesting the potential for PVDF ENM in DCMD applications.

An extractive membrane bioreactor (EMBR) for phenol-laden saline wastewater was set up in this study to investigate the variations of phenol removal, extracellular polymeric substance (EPS) release and microbial community dynamics. The gradual release of phenol and the total separation of salt were achieved by silicon rubber tube membrane. Only phenol (55.6-273.9mg/L) was extracted into microorganism unit from wastewaters containing 1.0-5.0g/L phenol and 35.0g/L NaCl. After 82d of EMBR operation, maximal 273.9mg/L of phenol was removed in EMBR. Low concentration of phenol in wastewater (2.5g/L) played a favorable effect on the microbial community structure, community and dynamics. The enumeration of Proteobacteria (30,499 sequences) significantly increased with more released EPS (82.82mg/gSS) to absorb and degrade phenol, compared to the virgin data without phenol addition. However, high concentration of phenol showed adverse effects on EPS release, microbial abundance and biodiversity.

Considerable efforts have been devoted to finding economic and simple preparation methods for polydimethylsiloxane (PDMS) superhydrophobic membrane in past decades. This study provides a simple method to electrospin PDMS membrane using poly (methyl methacrylate) (PMMA) as carrier polymer. Effects of PMMA concentration, PDMS/PMMA mass ratio and main parameters of electrospinning process (voltage and injection rate) were investigated to obtain superhydrophobic membrane with high water contact angle (WCA). A highest WCA of 163° could be obtained on the membrane surface fabricated by electrospinning solution containing PDMS: PMMA: tetrahydrofuran (THF): N,N-dimethylformamide (DMF) (mass ratio 1: 1: 8.88: 9.48) under applied voltage of 11 kV and injection rate of 0.1 mm/min. The superhydrophobic PDMS/PMMA membrane was further applied in membrane distillation process for desalination, and a high permeation flux of 39.61 L/m2 h and an excellent salt rejection of 99.96% were achieved during long-term MD process (24 h).

To minimize the health risks from antimony in aqueous environment, a polymer assisted ultrafiltration (PAUF) process with polyethersulfone (PES) membrane was employed to remove antimony for the first time. Effects of polymer, pH value and functional groups/Sb ions quantity ratio on antimony removal were systematically explored. Finally, antimony rejection efficiencies of 85.8 ± 0.9%–94.7 ± 1.9% were obtained with gradually reduced normalized water permeate flux from 1 to 0.61 ± 0.02 in 120 min PAUF process under the optimal conditions of polyethyleneimine (PEI), pH = 3 and functional groups/Sb ions quantity ratio = 8. Relevant mechanism investigations indicated that the macromolecule PEI-Sb complexes were formed mainly due to electrostatic interaction during complexation, and then were rejected in ultrafiltration by pore sieving. Meanwhile, ionic strength experiments indicated that the addition of NaCl resulted in significant decline (4.0 ± 0.8%–49.2 ± 3.2%) in antimony rejection efficiencies due to electric double-layer compressing and competition complexation. Moreover, membrane cleaning of 0.2% NaClO and PEI regeneration under pH value of 8 were performed to achieve sustainable cyclic PAUF with reused membrane and polymer. Simultaneously, antimony also could be recovered for reuse during the regeneration of PEI. Results of steady antimony rejection and water permeation demonstrated that this process is a viable alternative for sustainable antimony removal from aqueous environment.

Membrane distillation (MD) is an emerging water treatment technology suitable for hypersaline wastewater. However, membrane wetting is a primary obstacle to restrict its widespread industrial use. In this study, a superhydrophobic nanofibrous membrane (labeled as FZP) with high water contact angle of 162.3° and sliding angle of 9.8° was fabricated through fluorinating of zinc oxide (ZnO) blended electrospun polyvinylidene fluoride (PVDF) membrane. In comparison with neat and ZnO blended PVDF (ZP) nanofibrous membranes, FZP membrane has much better anti-wetting property due to its superhydrophobicity and higher liquid entry pressure (LEP) value when desalinating both pure NaCl solution and NaCl solutions with low-surface-tension sodium dodecyl sulfate (SDS) and sparingly soluble salt CaSO4. LEP values of membranes for SDS and CaSO4 contained feed solutions were calculated to be smaller than that for pure NaCl solution, accelerating the occurrence of membrane wetting. Temperature gradient across the membrane and Gibbs free energies of CaSO4 heterogeneous nucleation were further calculated to elucidate the wetting mechanism. Our results provide valuable insights for better developing superhydrophobic membrane and understanding its anti-wetting property in MD process.

Herein, changes in the degrading ability, populations and metabolism of microbes in activated sludge exposed to 60–350 mg L−1 phenol are thoroughly investigated. A phenol degradation experiment is conducted using activated sludge as inoculum over 140 days. The results suggest that the sludge efficiently degrades 250 mg L−1 phenol; however, it is unable to remove 350 mg L−1 phenol completely in two days, which might be caused by the decreased activities of catechol 1,2 dioxygenase (C12O) and catechol 2,3 dioxygenase (C23O). The specific oxygen uptake rate (SOUR) of the sludge and extracellular polymeric substances (EPS) generation are inhibited at the beginning of phenol degradation and then increase with phenol loading. A large amount of humic acid (HA) is produced during the degradation of 350 mg L−1 phenol due to cell decomposition. Illumina-MiSeq sequencing indicates that denitrifiers are competitive clusters at high phenol concentrations. The present study provides a comprehensive understanding of mechanisms of microbial responses to toxic compounds.

Porous modified polyacrylonitrile (PAN) with an ultrahigh percentage of amidoxime groups (UAPAN) was synthesized for the first time and used to adsorb antimonite (Sb(III)) and antimonate (Sb(V)) from aqueous solution. Fourier transform infrared (FT-IR), Zeta potential, X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) were adopted to characterize UAPAN and explore adsorption mechanism. Moreover, batch experiments were performed to investigate the influence of various adsorption parameters, including initial pH, contact time, temperature, coexisting ions and reusability on adsorption capacities. Results showed that the maximum adsorption capacities for Sb(III) and Sb(V) were 125.4 and 177.3 mg g−1, respectively, which were much higher than those of other adsorbents reported in literature. The adsorption thermodynamics was evaluated, indicating the spontaneous and endothermic adsorption. The adsorption isotherm was suitable to be modeled by Langmuir isotherm (R2 > 0.96). Results of FT-IR, Zeta potential and XPS indicated that adsorption was involved with electric charge attraction and ligand exchange. DFT further explained that better adsorption of Sb(V) on UAPAN than that of Sb(III) was caused by the higher adsorption energy, more favorable bond lengths and atom charge density. Accordingly, UAPAN is expected to be a compelling candidate for antimony decontamination from aqueous environment.

This study introduced a facile approach for high-performance electrospinning-phase inversion composite membrane, aiming at solving the low mechanical property, low mass transfer and salt leakage in extractive membrane bioreactor (EMBR) for phenol saline wastewater treatment. Composite membrane was fabricated through coating polydimethylsiloxane (PDMS) on electrospun PDMS membrane via dry phase inversion. Its surface was similar to that of phase inversion membrane while the cross section was uniformly distributed electrospun fibers in phase inversion layer, forming interconnected pore. The loose porous structure and high porosity were suitable for phenol permeation, and hydrophobic surface could reject the salt invasion. The tensile strength and elongation at break of composite membrane (56.5 μm thickness) were 1.7 MPa and 60.0%, making it stably operated in EMBR. Effects of different process variables were investigated, including membrane thickness, phenol concentration and wastewater flow rate. Remarkable performance of phenol biodegradation and salt rejection was achieved during EMBR operation, where the maximal phenol removal rate and conductivity variation in microorganism side were 508.9 mg L−1 d−1 and

Phenol-laden saline wastewaters can adversely affect water, groundwater, soil, organisms and ecosystems. Given that frequently-used biodegradation process is generally inhibited by salinity, this work aims to solve the problem through a novel configuration of external extractive membrane bioreactor (EMBR) for the objective of simultaneous phenol permeation, salt rejection and biodegradation. Contact angles of 160.9 ± 2.2° (water) and 0.0° (phenol) were observed on the electrospun polydimethylsiloxane/polymethyl methacrylate (PDMS/PMMA) membrane, suggesting this superhydrophobic/superorganophilic membrane was suitable for separating phenol from water-soluble salt. Phenol ranging from 14.1 ± 2.7 to 290.7 ± 10.4 mg/L (stages 1 to 8) was continuously permeated and completely biodegraded in external EMBR under a hydraulic retention time (HRT) of 24 h, which corresponded with detoxification performance improving from 6.3% to 70.5%. After phenol exposure of 8 stages, Proteobacteria and Saccharibacteria became the main phyla for microorganisms. Enumeration of functional genes (phe, amoA, narG, nirS) confirmed that phenol was mainly consumed by denitrifiers and other heterotrophs as the sole carbon and energy source via oxidation and ring cleavage. As bacterial responses, these genes’ proliferation was promoted under low phenol concentrations but inhibited under high phenol concentrations. Meanwhile, results of extracellular polymeric substances revealed that protein was the key substance in toxicity resistance, phenol adsorption and transfer.

Photovoltaic wastewater contains a large amount of thiourea that cannot be directly treated by biological methods because of its biotoxicity. In this study, a novel O

In order to observe the effect of magnetite during anammox start-up and stabilization stages, a novel up-flow anaerobic sludge blanket reactor using magnetite as a functional bio-carrier was designed and operated. Continuous experiments indicated that magnetite could shorten the endogenous denitrification stage and improve the nitrogen removal rate. The nitrogen removal performance increased from −0.06 to 1.17 kg N per m3 per d of R1 and from −0.08 to 1.18 kg N per m3 per d of R0 (as control reactor) on day 150. Analysis of variance (ANOVA) results of NRR during days 90–150 showed that R1 was statistically different from R0 (p = 0.045 < 0.05). The corresponding quantitative polymerase chain reaction results of nirS and nirK, fluorescence in situ hybridization results and Illumina MiSeq sequencing showed that proliferation of the anammox bacteria was promoted by magnetite with an increase of the nitrogen loading rate. The reduced N2O emission (25.06 ± 15.27 μmol L−1) combined with the reduced nosZ qPCR results (2.26 ± 0.029 × 106 copies per ng) revealed that this magnetite–anammox reactor also can serve as an ideal alternative for N2O emission reduction in ammonium-rich wastewater treatment.

To reduce operating costs and membrane fouling of conventional membrane bioreactors (cMBR), a novel MBR using a non-woven fabric membrane (nMBR) was constructed and the performance of the two MBRs was compared for anaerobic ammonium oxidation (anammox) cultivation. The results showed that the start-up period for the nMBR (44 days) was notably shorter than that for the cMBR (56 days), meanwhile the nMBR achieved a 2-times higher nitrogen removal rate (231.5 mg N per L per d) compared to the cMBR (112.3 mg N per L per d). Illumina MiSeq sequencing showed that Candidatus Kuenenia and Candidatus Jettenia were the main distinguished anammox bacteria. FISH analysis revealed that anammox bacteria predominated in both reactors, especially in the nMBR (58%) corresponding to a qPCR analysis of 1.07 × 109 copies per mL (day 120). N2O emission analysis confirmed the advantage of the nMBR in N2O reduction to reduce the influence of greenhouse gas emission while treating identical nitrogen. These results clearly demonstrated that nMBRs could be a prospective choice for anammox start-up and performance enhancement.

A distinct shift of bacterial community driven by organic matter (OM) and powder activated carbon (PAC) was discovered in the simultaneous anammox and denitrification (SAD) process which was operated in an anti-fouling submerged anaerobic membrane bio-reactor. Based on anammox performance, optimal OM dose (50 mg/L) was advised to start up SAD process successfully. The results of qPCR and high throughput sequencing analysis indicated that OM played a key role in microbial community evolutions, impelling denitrifiers to challenge anammox’s dominance. The addition of PAC not only mitigated the membrane fouling, but also stimulated the enrichment of denitrifiers, accounting for the predominant phylum changing from Planctomycetes to Proteobacteria in SAD process. Functional genes forecasts based on KEGG database and COG database showed that the expressions of full denitrification functional genes were highly promoted in RC, which demonstrated the enhanced full denitrification pathway driven by OM and PAC under low COD/N value (0.11).

Natural surface drinking water sources with the increasing chromophoric dissolved organic matter (CDOM) have profound influences on the aquatic environment and drinking water safety. Here, this study investigated the spatiotemporal variations of CDOM in Fengshuba Reservoir and its catchments in China. Twenty-four surface water samples, 45 water samples (including surface water, middle water, and bottom water), and 15 pore water samples were collected from rivers, reservoir, and sediment of the reservoir, respectively. Then, three fluorescent components, namely two humic-like components (C1 and C2) and a tryptophan-like component (C3), were identified from the excitation-emission matrix coupled with parallel factor analysis (EEM-PARAFAC) for all samples. For spatial distributions, the levels of CDOM and two humic-like components in the reservoir were significantly lower than those in the upstream rivers (p

The long start-up time of anaerobic ammonium oxidation (anammox) process hinders the widespread application of anammox technology in practical wastewater treatment when anammox seed sludge is not available. Meanwhile, the production of nitrate cannot meet the increasingly more strict discharge standards. To combine the chemical nitrate reduction to ammonium with biological nitrogen removal, two anammox upflow anaerobic sludge blanket reactors packed with different types of zero-valent iron (ZVI), microscale ZVI (mZVI) and nanoscale ZVI (nZVI), were developed to accelerate the start-up of anammox process. The results revealed that anammox start-up time shortened from 126 to 105 and 84 days with the addition of mZVI and nZVI. The nitrogen removal performance was also improved remarkably by adding ZVI, especially in the start-up stage. The value of dissolved oxygen showed that ZVI could be regarded as a useful deoxidant to create anaerobic condition for the proliferation of anammox bacteria. ZVI was favorable for the secretion of EPS, which would represent the activity of anammox bacteria. The result of real-time quantitative PCR (qPCR) further confirmed that the proliferation of anammox bacteria was enhanced by ZVI.

To further expand the application of anammox biotechnology, a novel zero-valent iron-assembled upflow anaerobic sludge bed reactor was employed to strengthen anammox performance under low temperature and shock load. Packed with sponge iron and polyester sponge, this novel reactor could speed up the recovery of anammox activity in 12 days and improve the adaptability of anammox bacteria at the temperature of 10–15 °C. The high nitrogen loading rate of 1109.2 mg N/L/day could be adapted in 27 days and the new nitrogen pathway under the effect of sponge iron was clarified by batch experiment. Moreover, the real-time quantitative PCR analysis and Illumina MiSeq sequencing verified the dominant status of Candidatus Kuenenia stuttgartiensis and planctomycete KSU-1, as well as demonstrated the positive role of sponge iron on anammox microorganisms’ proliferation. The findings might be beneficial to popularize anammox-related processes in municipal and industrial wastewater engineering.

Facilities adopting anaerobic granular sludge are widely used for the treatment of high strength wastewater, and hence collect many polybrominated diphenyl ethers (PBDEs), especially decabromodiphenyl ether (BDE-209). We initiated a detailed investigation to gain insight into the bioremoval of BDE-209 by anaerobic granules. Influenced by solution pH, ionic strength and temperature, the equilibrium time was ∼6 h and the biosorption amount increased from 0.099 to 1.25 mg/g suspended sludge with the increase of BDE-209 concentrations. Kinetic studies indicate that BDE-209 biosorption on anaerobic granules follows the pseudo second-order kinetic model. Isotherm analysis exhibits that the Langmuir model fits the data at low temperature, while the Freundlich model is appropriate at room temperature. Thermodynamic analysis shows that biosorption followed an endothermic path and was nonspontaneous with negative value of Δ G 0 . XPS and FTIR spectra confirmed that oxygen and nitrogen atoms notably contributed to BDE-209 binding.