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• Basic principles and affecting parameters of electrospinning process are overviewed. • Summary of application of electrospinning biohybrid technology. • Applications of electrospinning biohybrid technology targeting different pollutants. • Microbial selection, fabricating routes of electrospinning biohybrid composites. • Bioremediation capacity of electrospinning biohybrid technology in water treatment. • The actual state and future challenges of electrospinning biohybrid technology. With the rapid development of nanotechnology and additive manufacturing industries, electrospinning for the fabrication of high-performance nanofibers has attracted increasing attention. The rapid development of biohybrid environmental remediation technology has led to sustainable water treatment materials aimed at different pollutants and application scenarios. The coupling of biohybrid materials with electrospinning technology further addresses potential drawbacks of traditional biomaterials, such as low activity, poor diffusion, and loss of biological activity. In recent years, advanced techniques for constructing biohybrid fibers have been achieved through electrospinning methods such as fiber encapsulation, microtube encapsulation, and co-electrospinning, utilizing microbial cells (bacteria, algae, yeast, etc.). In this review, we firstly introduce the basic principle of electrospinning technology and parameters affecting spinning process. Then systematically analyze the microbial selection, material synthesis routes, and degradation efficiency of electrospinning biohybrid technology in water treatment processes targeting different pollutants, while assessing the application prospects or drawbacks of each case. Finally, we summarize and prospect the technical characteristics, current issues, and industrial prospects of electrospinning biohybrid technology. [ABSTRACT FROM AUTHOR]

[Display omitted] • A core–shell QQ-encapsulated structure was prepared by a standardized method. • SIPN shell enables excellent biocontainment with physical and chemical stability. • The anti-biofouling and phosphorus removal were enhanced in QQ microcapsule MBR. • QQ microcapsule promoted the application of QQ media for anti-biofouling in MBR. Microbial quorum quenching (QQ) has been proven to be a sustainable anti-biological fouling strategy for membrane bioreactors (MBR), but the long-term stability and practical application in MBR were uncertain. We reported a novel semi-interpenetrating network (SIPN) hydrogels-based design of QQ bacteria (Rhodococcus sp. BH4) encapsulation for both biofouling control and enhancement of organic pollutants removal in MBR. The microcapsule included the alginate core, chitosan thin intermediate compartment and SIPN (sodium alginate / polyacrylamide) shell, which exhibited near-perfect biocontainment, including preventing detectable QQ bacteria escape and improving mechanical strength. The QQ-microcapsules in the MBR demonstrated its significant anti-biofouling effect for treating synthetic wastewater (i.e., membrane fouling was delayed by 233%-280% compared to the control MBR membrane). Meanwhile, the efficiency of phosphorus removal was developed in QQ-microcapsule MBR because of the enhanced phosphorus removal triggered by the flocculation of polyacrylamide (PAM) fraction in SIPN. This promising QQ media brings the broad potential for biofouling control and long-term efficient operation in actual MBR wastewater treatment. [ABSTRACT FROM AUTHOR]

Photocatalytic membranes were fabricated via vacuum assisted layer-by-layer (LBL) self-assembly of 0D-2D Bi 2 MoO 6 -g-C 3 N 4 on a PDA coated thin-film composite PVDF substrate by Schiff base reaction. The composite membrane possesss excellent photocatalytic activity under visible light. [Display omitted] A Self-cleaning surface can efficaciously solve the problem of irreversible contamination buildup on filtration membranes. Photocatalytic membranes were fabricated via vacuum assisted layer-by-layer (LBL) self-assembly of 0D-2D Bi 2 MoO 6 -g-C 3 N 4 on a PDA coated thin-film composite PVDF substrate by Schiff base reaction. The rejection rate of the simulated polysaccharide was more than 90%, and that of the simulated protein was more than 80%. The combination of the membrane and the photocatalyst promoted the degradation of tetracycline hydrochloride by the composite membrane to 67.85% when original membranes had minor effect. Under visible light, reversible radiation pollutants (R r) gradually replaced irreversible pollutants (R ir) as the main pollutants. The flux recovery ratio (FRR) of 0D-2D Bi 2 MoO 6 -g-C 3 N 4 /PVDF membrane was 85% after being irradiated with visible light for 30 min. The flux recovery rate of contaminated photocatalytic membrane remained 75%, and the rejection was maintained in a stable range after four cycles of the cleaning operation under visible light. The results indicated that the excellent photocatalytic performance of 0D-2D Bi 2 MoO 6 -g-C 3 N 4 photocatalysis material and the increase of multi-dimensional functional layer morphology on pollutant contact area improved the mechanical stability, interception performance and self-cleaning performance of the composite membrane. This work not only builds a new type of composite coating membranes, but also help us to further understand the relationship between the dimensions of photocatalytic materials and the improvement of photocatalytic membrane performance. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • MCU-C 3 N 4 was fabricated by supramolecular strategy. • MCU-C 3 N 4 /PVDF membranes were assembled by vacuum filtration with crosslinkers. • MCU-C 3 N 4 /PVDF membranes had excellent photocatalytic degradation of RhB and TC. • MCU-C 3 N 4 /PVDF membranes exhibited well self-cleaning properties. Abstract Recently, the application of membranes faces a big challenge due to membrane fouling, to alleviate this situation, the hybridization of photocatalysis and membrane filtration has aroused significant attention. In this study, we firstly introduced melamine, cyanuric acid and urea in dimethyl sulfoxide (DMSO) as precursors to fabricated the MCU(DMSO)-C 3 N 4 material with excellent photocatalytic performance, and immobilized it on PVDF membranes by vacuum filtration, subsequently adding polyethylene glycol and glutaraldehyde as crosslinkers from MCU-C 3 N 4 /PVDF membrane. The results demonstrate that with the MCU-C 3 N 4 ratio increasing, the membrane flux was gradually decreased. Besides, the photocatalytic efficiencies of MCU-C 3 N 4 /PVDF for rhodamine B (RhB) and tetracycline hydrochloride (TC) degradation are 84.24% and 71.26% respectively, which are about 8 times higher than that of the original membrane. To evaluate antifouling performance of photocatalytic membranes, we conducted a four-stage filtration system, and the flux recovery ratio (FRR) of MCU-C 3 N 4 /PVDF membranes reached over 80% (optimum 91%) under visible light irradiating (λ > 420 nm) for 30 min. Meanwhile, under visible light irradiation reversible fouling (Rr) gradually became the dominant fouling factor instead of the irreversible fouling (Rir), indicating the excellent antifouling performance of MCU-C 3 N 4 /PVDF membranes. This novel method to modify membranes with MCU-C 3 N 4 gives insight to photocatalytic and self-cleaning properties of photocatalytic composite membranes, providing theoretical basis for their broad application. [ABSTRACT FROM AUTHOR]

A low-cost and metal-free semiconductor-based photocatalyst driven by visible light has attracted great interest for water remediation. A relatively larger-surface area carbon nitride consisting of thin nanosheets is synthesized, firstly adopting melamine (M), cyanuric acid (C), urea (U) and dimethyl sulfoxide (DMSO) as the starting materials to form the supramolecular carbon nitride MCU(DMSO)-C 3 N 4 . Physical, chemical, and optical properties of the resulting samples were characterized. The photocatalytic performance of the MCU(DMSO)-C 3 N 4 was evaluated under visible light irradiation using rhodamine B (RhB), tetracycline hydrochloride (TC), and ciprofloxacin (CIP) as target pollutants. Results showed that MCU-C 3 N 4 exhibited much higher photocatalytic activity than pure g-C 3 N 4 , and when M, C, and U in DMSO with certain molar ratio (1:1:1) exhibited the highest activity. The larger surface area with more active reaction sites, increased bandgap with stronger REDOX ability, and higher separation efficiency of photogenerated electron-hole pairs contributed to higher photocatalytic activity. The photo-degradation is dominant by the active species (h + and O 2 − ) and converted product ( OH). This exploration of MCU(DMSO)-C 3 N 4 may open a window to the design of low-cost and highly efficient photocatalysis degradation systems for various wastewater treatments. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Recent studies on pharmaceuticals removal in MBR treatment process are reviewed. • MBR process and operation parameters have effects on pharmaceuticals removal. • Degradation mechanism of pharmaceuticals and transformation product are analyzed. • Pharmaceuticals are adsorbed by sludge, membrane, and exogenous substance. • Knowledge gaps and recommendation for future research needs are proposed. Abstract Pharmaceuticals in surface waters and wastewater treatment plants (WWTPs) as emerging pollutants have become a major concern. In comparison with other wastewater treatments, removal of pharmaceuticals in MBR has received much attention. This review presents the source and occurrence of pharmaceuticals in WWTPs influents. Experimental studies related to the removal of pharmaceuticals during MBR treatment, key affecting factors (including the different stages of MBR process configuration and the process parameters), and the underlying mechanisms proposed to explain the biodegradation and adsorption behaviors, have been comprehensively discussed. Several transformation products of pharmaceuticals are also reviewed in this paper. Furthermore, further research is needed to gain more information about the multiple influence factors of the pharmaceuticals elimination, appropriate methods for promoting pharmaceuticals elimination, more essential removal pathways, effect of pharmaceuticals on membrane fouling, and the detection and analysis of transformation products. [ABSTRACT FROM AUTHOR]

Extracellular polymeric substances (EPS) are present both outside of the cells and in the interior of microbial aggregates, and account for a main component in microbial aggregates. EPS can influence the properties and functions of microbial aggregates in biological wastewater treatment systems, and specifically EPS are involved in biofilm formation and stability, sludge behaviors as well as sequencing batch reactors (SBRs) granulation whereas they are also responsible for membrane fouling in membrane bioreactors (MBRs). EPS exhibit dual roles in biological wastewater treatments, and hence the control of available EPS can be expected to lead to changes in microbial aggregate properties, thereby improving system performance. In this review, current updated knowledge with regard to EPS basics including their formation mechanisms, important properties, key component functions as well as sub-fraction differentiation is given. EPS roles in biological wastewater treatments are also briefly summarized. Special emphasis is laid on EPS controlling strategies which would have the great potential in promoting microbial aggregates performance and in alleviating membrane fouling, including limitation strategies (inhibition of quorum sensing (QS) systems, regulation of environmental conditions, enzymatic degradation of key components, energy uncoupling etc.) and elevation strategies (enhancement of QS systems, addition of exogenous agents etc.). Those strategies have been confirmed to be feasible and promising to enhance system performance, and they would be a research niche that deserves further study. [ABSTRACT FROM AUTHOR]

Quorum sensing (QS) is a communication process between cells, in which bacteria secrete and sense the specific chemicals, and regulate gene expression in response to population density. Quorum quenching (QQ) blocks QS system, and inhibits gene expression mediating bacterial behaviors. Given the extensive research of acyl-homoserine lactone (AHL) signals, existences and effects of AHL-based QS and QQ in biological wastewater treatments are being subject to high concern. This review summarizes AHL structure, synthesis mode, degradation mechanisms, analytical methods, environmental factors, AHL-based QS and QQ mechanisms. The existences and roles of AHL-based QS and QQ in biomembrane processes, activated sludge processes and membrane bioreactors are summarized and discussed, and corresponding exogenous regulation strategy by selective enhancement of AHL-based QS or QQ coexisting in biological wastewater treatments is suggested. Such strategies including the addition of AHL signals, AHL-producing bacteria as well as quorum quenching enzyme or bacteria can effectively improve wastewater treatment performance without killing or limiting bacterial survival and growth. This review will present the theoretical and practical cognition for bacterial AHL-based QS and QQ, suggest the feasibility of exogenous regulation strategies in biological wastewater treatments, and provide useful information to scientists and engineers who work in this field. [ABSTRACT FROM AUTHOR]

With the increasing number of constructed wetlands being built, the modelling of wetland function and performance is valuable. This work examines the efficacy of applying a numeric model (SubWet 2.0) originally designed for horizontal subsurface flow wetlands to model wastewater treatment within vertical subsurface flow constructed wetlands (VSSF-CWs). The treatment efficiencies of two VSSF-CWs with substantially different influent characteristics, one in Canada and one in China, were modelled with SubWet 2.0 and simulated values were then compared to observed values to determine how closely SubWet 2.0 reflects the actual observed performance of these wetlands. The model was calibrated to each wetland with observed data that had been collected prior to the simulations. The correlation coefficient ( R ) and Nash–Sutcliff coefficient of efficiency (NSE) were used to evaluate the modelling performance for 5-day biochemical oxygen demand (BOD 5 ), ammonium nitrogen, nitrate nitrogen and total phosphorous (TP). The results showed that the modelling performance for TP and BOD 5 was better for these parameters than that observed for ammonium nitrogen and nitrate nitrogen for either of the two wetlands. For TP and BOD 5 , the correlation coefficient R achieved a value of 0.79 for the wetland receiving stormwater and exceeded this value for the Canadian wetland receiving domestic wastewaters. For nitrate nitrogen, the wetland treating domestic waste showed a correlation coefficient R as high as 0.97, while the wetland treating stormwater runoff had a correlation coefficient R of 0.48. For ammonium nitrogen, both wetlands showed low correlation coefficients with values of 0.70 and 0.60 for domestic wastewater and for stormwater runoff, respectively. This study demonstrated that SubWet 2.0 is suitable for the modelling of VSSF-CWs. The two case studies, with substantial differences in the characteristcs of the influents, demonstrated that Subwet 2.0 is a versatile and robust tool for modelling of constructed wetlands. [ABSTRACT FROM AUTHOR]

Abstract: Micellar-enhanced ultrafiltration (MEUF) is a promising technology developed for treating the wastewater containing metal ions or organic pollutants. One of the greatest problems in MEUF is membrane fouling which is mainly caused by concentration polarization, gel layer or cake formation caused by the deposition of surfactant micelles on the membrane surface and surfactant adsorption in the membrane interior. In this study, surfactant sodium dodecyl sulfate (SDS), which was used in membrane separation as colloidal particles, caused the flux decline. The transmembrane pressure (TMP) and feed concentration of SDS had significant influences on the flux. This paper presented that the lower TMP had a smaller effect on membrane fouling, and when SDS concentration was around the critical micelle concentration (CMC), lower permeate flux and higher additional membrane fouling resistance were obtained. The effects of three kinds of hydraulic flushing methods on membrane permeate flux were investigated, including periodic forward flushing, periodic backwashing and forward flushing followed by backwashing. It was found that when the periodic combined flushing interval was 10min, forward flushing and backwashing phase times were 150s and 90s, respectively, and that combined flushing was more conductive to permeate flux recovery in this study. [Copyright &y& Elsevier]

• A phosphorus-removal fungus MSP8 was isolated and identified as Aureobasidium sp. • MSP8 has a salinity resistance with range of 0–17%. • 77.2% phosphorus removal can be achieved by MSP8 at the optimal salinity of 5%. • Phosphorus removal pathway of MSP8 was preliminarily revealed. • MSP8 showed good potential for removing phosphorus in actual high-salt wastewater. Efficient halotolerant phosphorus accumulation microorganisms are of great significance for the treatment of high-salt wastewater. In this study, a halotolerant fungus strain named MSP8 was isolated and identified as Aureobasidium sp. Salinity resistance results showed that strain MSP8 can resist the salinity from 0% to 17%, and 77.2% phosphorus removal was achieved at the optimal salinity of 5%. The strain also showed wide environmental adaptability (pH of 3–7; temperature of 20–30 °C). Batch tests and scanning electron microscope equipped with an energy dispersive spectrometer (SEM-EDS) characterization results verified the key role of extracellular polymeric substance (EPS) secreted by MSP8 in phosphorus removal. The actual brewery and chemical wastewater treatments exhibited that above 53.5% of phosphorus can be removed by MSP8. The excellent adaptation of MSP8 made it a potential candidate for phosphorus removal especially in saline wastewater treatment. [ABSTRACT FROM AUTHOR]

• Microbial community dynamics are analyzed under the condition of exogenous QQ. • The change of sludge's biofouling propensity is investigated when adding exogenous QQ. • Exogenous QQ can reduce the species diversities of MBRs, especially in the short term. • Exogenous QQ can enhance biofouling propensity of sludge itself in the short term. • The enhancing of biofouling propensity of sludge depends on the dynamics of situ QS and QQ bacteria. Recently, bacterial quorum quenching (QQ) has been proven as a novel approach for biofouling mitigation in membrane bioreactors (MBRs). The information about microbial community is vital for the development of QQ strategies. Also, the change of microbial community may affect the biofouling propensity of sludge. In this study, the effects of exogenous QQ on microbial community dynamics in MBRs were investigated, along with biofouling propensity of activated sludge. QQ MBR dosed with exogenous QQ bacteria exhibited a better anti-biofouling, whereas the wastewater treatment performance was almost no difference compared with control MBR. As for the microbial community, exogenous QQ had an impact on both the bacterial diversities and community composition, especially for the quorum sensing (QS) and QQ bacteria in situ. The addition of exogenous QQ could reduce the QQ ability of sludge itself in the short term, and enhance its biofouling propensity. These findings provided new insights for the development of QQ strategies. [ABSTRACT FROM AUTHOR]

• First application of xurographic fabrication technology to construct micro-MFC. • The cost of fabricating the sensor is lower than 0.5 USD. • The response time of the BOD sensor could be as short as 1.1 min. • The sensor can cover a wide range of BOD between 20−490 mg/L. The rapid quantification of biological oxygen demand (BOD) plays an important role in environmental management, for instance, wastewater treatment. This study used xurographic fabrication technology to rapidly fabricate a low cost miniaturized microbial fuel cell (MFC) and demonstrated its suitability to measure BOD. The miniaturized sensor could be fabricated in 10 min with low cost of $0.5 U.S. per device. The reaction volume was designed to be 1.8 μL to obtain faster response time. The sensor was tested using sodium acetate (NaAc) as a model BOD analyte. It could response to a wide range of BOD concentration between 20 and 490 mg/L which would cover the majority range of wastewater BOD concentration in a wastewater treatment plant. The response time of this microsensor was 1.1 min which was significantly shorter than other conventional methods for BOD measurements (5 days). This study demonstrated that the use of xurographic methods to fabricate MFCs could enable rapid fabrication of microsensors to measure BOD in a rapid manner. This study also identified the potential of the sensor for application in wastewater treatment plants to monitor BOD and provide guidance for controlling treatment processes. [ABSTRACT FROM AUTHOR]