Electroactive biofiltration dynamic membrane: A new hope for wastewater treatment

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Credit: Chengxin Niu et al.

A recent study published in Engineering presents a novel approach to wastewater treatment and membrane fouling mitigation. The research, led by Zhiwei Wang from Tongji University, focuses on the development of an electroactive biofiltration dynamic membrane (EBDM).

The increasing scarcity of freshwater resources and the need for more efficient wastewater treatment have driven the search for innovative solutions. Anaerobic membrane bioreactors (AnMBRs) have shown promise, but membrane fouling remains a significant challenge. Dynamic membranes (DMs) can help, but their fouling layer growth needs to be better managed. The EBDM aims to address these issues by integrating an electric field into the DM system.

The researchers established an anaerobic conductive dynamic membrane bioreactor to study the EBDM system. They compared an electrochemical anaerobic dynamic membrane bioreactor (E-AnDMBR) with a control anaerobic dynamic membrane bioreactor (C-AnDMBR) over a 240-day period. The E-AnDMBR was operated with an applied voltage, while the C-AnDMBR functioned without voltage.

The results were remarkable. The EBDM in the E-AnDMBR exhibited an ultralow fouling rate, with a transmembrane pressure of less than 2.5 kPa throughout the operation. It achieved a high COD removal efficiency of over 93% and maintained a turbidity of around 2 NTU in the effluent. Moreover, the methane productivity in the E-AnDMBR was 7.2% higher than that in the C-AnDMBR.

Morphological analysis revealed that the EBDM acted as an efficient biofilter with an ordered-clogging and step-filtered structure. The electric field modified the physicochemical properties of the biomass, reducing the fouling potential. For example, it decreased the zeta potential of the sludge, increased the floc size, and reduced the viscosity and EPS concentration.

The EBDM also had a significant impact on the microbial metabolism. Metagenomic sequencing showed that continuous electrical stimulation promoted the development of an electroactive fouling layer with enhanced microbial metabolic functionality. It increased the relative abundance of Geobacter on the anode, which facilitated extracellular electron transfer and methane production.

This study demonstrates that the EBDM system is a promising technology for wastewater treatment. It effectively controls membrane fouling, enhances effluent quality, and improves methane productivity. The findings contribute to a better understanding of the interactions between electric fields and electroactive biofilms, providing a new option for enhancing membrane performance in wastewater treatment systems.

The paper “Development of Electroactive Biofiltration Dynamic Membrane (EBDM) for Enhanced Wastewater Treatment and Fouling Mitigation: Unraveling the Growth Equilibrium Mechanisms of Fouling Layer,” is authored by Chengxin Niu, Wei Shi, Zhouyan Li, Zhiwei Qiu, Yun Guo, Zhiwei Wang. Full text of the open access paper: https://doi.org/10.1016/j.eng.2025.02.003. For more information about Engineering, visit the website at https://www.sciencedirect.com/journal/engineering.

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Journal

Engineering

DOI

10.1016/j.eng.2025.02.003 

Article Title

Development of Electroactive Biofiltration Dynamic Membrane (EBDM) for Enhanced Wastewater Treatment and Fouling Mitigation: Unraveling the Growth Equilibrium Mechanisms of Fouling Layer

 

Pediatric investigation review discusses the challenges, innovations, and future directions in dengue vaccine development

The review details the historical and current status of dengue vaccine development, underscoring key themes of future research

Pediatric Investigation

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Dengue fever caused by a flavivirus named DENV is a major global health challenge, risking almost half of the world’s population. Since the early 20th century, the scientific community has faced multiple challenges to develop effective dengue vaccines. This spanned a variety of techniques – from the use of ox bile to weaken DENV to the chemical processing of DENV-infected mosquitoes! However, the limitations of these techniques and the urgent need to save millions of people from the infection in its endemic regions, led to the development of more sophisticated dengue vaccines.

In a recent review published in Pediatric Investigation on 15 April 2025, lead authors Professor Kevin C. Kain from the University of Toronto, Canada, and Dr. Ran Wang, Associate Professor at the Capital Medical University, China, discuss the current status and implications of dengue vaccines like CYD-TDV, TAK-003, and Butantan-DV while exploring the challenges in Dengue vaccine development like ADE, and proposes future directions in this field.

DENV has four serotypes (DENV-1 to DENV-4) and triggers both protective and pathogenic immune responses. Serotype-specific immune responses are typical when infected for the first time, whereas secondary infection may lead to more severe dengue due to ADE. “ADE is initiated when immune complexes of DENV and IgG antibodies bind to Fcγ receptors (FcγR) on myeloid cells. This suppresses antiviral defenses and enhances viral replication,” explains Professor Kain. This is an important aspect to consider while designing vaccines for dengue.

The review draws from insights and implications from three Dengue vaccines—CYD-TDV (Dengvaxia) was the first licensed dengue vaccine and showed efficacy in phase III clinical trials. However, it was found to have reduced protection against DENV-1, DENV-2, and DENV-3. Moreover, this vaccine was only recommended for individuals with confirmed prior DENV infection, limiting its practical application. Further, vaccination regime of three doses over 12 months, was particularly difficult to achieve in resource-limited settings. Due to these reasons, CYD-TDV was withdrawn from widespread use, although the WHO still recommends it for individuals aged 9-45 years with prior DENV infection.

The second vaccine—TAK-003 – was evaluated over a four-and-a-half-year-long Phase III trial across eight countries where Dengue is endemic. With an overall efficacy of 61.2% (against current dengue infection) and 84.1% (against hospitalized cases), it offered strong protection against DENV-1 and DENV-2 serotypes. But, due to the insufficient number of cases of the other two serotypes, TAK-003’s efficacy against these could not be evaluated. This vaccine has a two-dose regimen, presenting logistical challenges as in the case of CYD-TDV.

Contrary to the above cases, the Butantan-DV vaccine with its single-dose regimen proved to have an edge over the others in simplifying vaccination where healthcare facilities were limited. Dr. Wang explains further about this vaccine, “A 2-year analysis reported an overall efficacy of 73.6% in sero-naïve individuals and 89.2% in those with prior dengue exposure, with protection against DENV-1 (89.5%) and DENV-2 (69.6%)”. Also, in a study that spanned more than 3 years, Butantan-DV demonstrated an 89% decrease in severe dengue and dengue with warning signs. However, the efficacy of this vaccine against DENV-3 and DENV-4 is yet to be established. Although the current dengue vaccines exhibit effective reduction of severe and fatal dengue in clinical trials, their impact on individuals aged above 60 years is still unclear.

The possibility of severe dengue after vaccination has been a significant challenge, particularly thought to be driven by ADE. When non-neutralizing, cross-reactive antibodies recognize conserved epitopes on the DENV envelope protein, it triggers immune responses that weaken antiviral activity, leading to severe disease. “Understanding the role of conserved epitopes and FcγR signaling in ADE is crucial for dengue vaccine development, and ADE issues in real world may only be revealed through efficacy studies in phase IV clinical trials of vaccines”, comments Professor Kain.

Looking ahead, global collaboration among researchers, health agencies, and vaccine developers will be essential to advance dengue vaccine research. Future efforts should explore diverse platforms like mRNA vaccines and focus on avoiding ADE. Priorities include: 1) Phase IV trials to refine strategies, 2) vaccines adaptable across populations and serotypes, and 3) region-specific formulations targeting local DENV variants.

With global collaboration, advanced vaccine platforms, and a better understanding of ADE, we may finally be on the path toward eliminating dengue.

 

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Reference

DOI: https://doi.org/10.1002/ped4.70005

 

About Professor Kevin C. Kain

Dr. Kain is a Professor of Medicine at the Department of Medicine, Tropical Disease Unit, University of Toronto, Canada, as well as the Director of the Sandra A. Rotman Laboratories, Sandra Rotman Centre for Global Health, University Health Network-Toronto General Hospital, Canada. Dr. Kain has extensively worked in the tropics and sub-tropics on global health research and neglected tropical diseases like malaria and dengue. His research interests include new diagnostics for viral diseases, drugs and vaccines for prevention of malaria, and molecular mechanisms behind severe and cerebral malaria. He is widely regarded as an expert in tropical diseases, with over 500 publications to his credit having more 27,000 citations.

 

About Associate Professor Ran Wang

Dr. Ran Wang is an associate professor of infection and virology at the Beijing Children's Hospital, Capital Medical University, Beijing, China. Dr. Wang’s field of expertise includes research on the immune cross-reactivity across different types of flavivirus, such as Japanese encephalitis virus, Dengue virus, and Zika virus. He is also interested in the field of vaccination, focusing on viral immunology, T cell immunity, and infection. Dr. Wang is also engaged in Epstein–Barr virus-related research, focusing on immune regulation and disease pathogenesis.

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Journal

Pediatric Investigation

DOI

10.1002/ped4.70005 

Method of Research

Literature review

Subject of Research

Not applicable

Article Title

Advancing dengue vaccine development: Challenges, innovations, and the path toward global protection

 

Synchrotron in a closet: Bringing powerful 3D X-ray microscopy to smaller labs

A new design makes a technique for studying metals, ceramics and rocks available in a standard laboratory, expanding access for students, academic researchers and industry

Peer-Reviewed Publication

University of Michigan

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For the first time, researchers can study the microstructures inside metals, ceramics and rocks with X-rays in a standard laboratory without needing to travel to a particle accelerator, according to a study led by University of Michigan engineers. 

 

The new technique makes 3D X-ray diffraction—known as 3DXRD—more readily accessible, potentially enabling quick analysis of samples and prototypes in academia and industry, as well as providing more opportunities for students.

 

3DXRD reconstructs 3D images using X-rays taken at multiple angles, similar to a CT scan. Instead of the imaging device rotating about a patient, a few-millimeters-wide material sample rotates on a stand in front of a powerful beam with about a million times more X-rays than a medical X-ray. 

 

The huge X-ray concentration produces a micro-cale image of the tiny fused crystals that make up most metals, ceramics and rocks—known as polycrystalline materials. 

 

Results help researchers understand how materials react to mechanical stresses by measuring thousands of individual crystals' volume, position, orientation and strain. For example, imaging a sample from a steel beam under compression can show how crystals respond to bearing the weight of a building, helping researchers understand large-scale wear.

 

Synchrotrons were once the only facilities able to produce enough X-rays for 3DXRD as electrons spit off scads of X-rays as they travel through circular particle accelerators, which can then be directed into a sample.

 

While synchrotron X-ray beams produce state-of-the-art detail, there are only about 70 facilities world-wide. Research teams must put together project proposals for "beam time." Accepted projects often must wait six months to up to two years to run their experiments, which are limited to a maximum of six days. 

 

In an effort to make this technique more widely available, the research team worked with PROTO Manufacturing to custom build the first laboratory-scale 3DXRD. As a whole, the instrument is about the size of a residential bathroom, but could be scaled down to the size of a broom closet.

 

"This technique gives us such interesting data that I wanted to create the opportunity to try new things that are high risk, high reward and allow teachable moments for students without the wait-time and pressure of synchrotron beam time," said Ashley Bucsek, U-M assistant professor of mechanical engineering and materials science and engineering and co-corresponding author of the study published in Nature Communications.

 

Previously, small-scale devices could not produce enough X-rays for 3DXRD because at a certain point, the electron beam pumps so much power into the anode—the solid metal surface that the electrons strike to make X-rays—that it would melt. Lab-3DXRD leverages a liquid-metal-jet anode that is already liquid at room temperature, allowing it to take in more power and produce more X-rays than once possible at this scale. 

 

The researchers put the design to the test by scanning the same titanium alloy sample using three methods: lab-3DXRD, synchrotron-3DXRD and laboratory diffraction contrast tomography or LabDCT—a technique used to map out crystal structures in 3D without strain information. 

 

Lab-3DXRD was highly accurate, with 96% of the crystals it picked up overlapping with the other two methods. It did particularly well with larger crystals over 60 micrometers, but missed some of the smaller crystals. The researchers note that adding a more sensitive photon-counting detector, which detects the X-rays that are used to build the images, could help catch the finest-grained crystals.

 

With this technique available in-house, Bucsek's research team can try new experiments, honing parameters to prepare for a larger experiment at a synchrotron.

 

"Lab-3DXRD is like a nice backyard telescope while synchrotron-3DXRD is the Hubble Telescope. There are still certain situations where you need the Hubble, but we are now well prepared for those big experiments because we can try everything out beforehand," Bucsek said.  

 

Beyond enabling more accessible experiments, lab-3DXRD allows researchers to extend projects past the synchrotron six day limit, which is particularly helpful when studying cyclic loading—how a material responds to repeated stresses over thousands of cycles.

 

First author and co-corresponding author Seunghee Oh, a research fellow in mechanical engineering at the time of the study, now works in the X-ray Science Division at Argonne National Laboratory.

 

The research is funded by the National Science Foundation (CMMI-2142302; DMR-1829070) and the U.S. Department of Energy (Award DE-SC0008637). 

 

Researchers from PROTO Manufacturing also contributed to the study.

 

LabDCT was performed at the Michigan Center for Materials Characterization.

Study: Taking three-dimensional X-ray diffraction (3DXRD) from the Synchrotron to the laboratory scale (DOI: 10.1038/s41467-025-58255-x)

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Journal

Nature

DOI

10.1038/s41467-025-58255-x 

 

Multiscale fibrous reinforcements yield high-performance construction composite

Higher Education Press

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Schematic of multiscale fiber-reinforced cementitious composite.

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Credit: Peizhao Zhou et al.

A recent study published in Engineering by Peizhao Zhou and Peng Feng from Tsinghua University introduces a novel construction material—flexible ultra-high performance reinforced cementitious composite (FHPRC). This material holds great potential for revolutionizing the construction industry with its excellent mechanical properties.

The research focuses on the concept of multiscale fibrous reinforcements in cementitious matrices. By carefully tailoring the types, sizes, and volume fractions of fibers, the researchers optimized the tensile behavior of the composite. They combined the superior strength and durability of ultra-high performance concrete (UHPC) with the high ductility and crack control capacity of engineered cementitious composite to create FHPRC. This new material boasts a compressive strength of 160 MPa, a tensile strength of 36 MPa, an ultimate tensile strain of over 1%, a crack width of less than 0.1 mm, and significant post-yield stiffness.

To validate the effectiveness of FHPRC, the researchers conducted a series of experiments. They fabricated 30 plate specimens from 10 groups and subjected them to four-point bending tests. The tests comprehensively investigated the effects of strain-hardening cementitious composite (SHCC) type, fiber-reinforced polymer () type, and configuration on the flexural behavior of the composite. The experimental results showed that carbon FRP (CFRP) textiles, when combined with short steel fibers, significantly enhanced the mechanical properties of UHPC. For example, compared with unreinforced UHPC, the load-carrying capacity of UHPC–FRP plates increased by up to 163.5%, and the ultimate deflection improved by 331.7%.

In addition to the experimental investigation, the researchers also developed numerical models to analyze the flexural behavior of FHPRC. They established an equivalent constitutive model for layered shells based on the smeared crack approach, which simplifies the numerical effort required to simulate intense matrix cracking. The model was used to simulate three independent bending experiments, and the results demonstrated its accuracy in predicting the mechanical behavior of FHPRC. Compared with the conventional uncorrected model, the proposed model reduced the root mean square errors of the ultimate deflection and load-carrying capacity by 93.1% and 90.0%, respectively.

The development of FHPRC provides valuable insights into the field of advanced construction materials. Its high strength, ductility, and crack control capacity make it suitable for a wide range of applications in super-high-rise, long-span spatial, and ultra-thin shell structures. Although the study did not explore the effects of nanomaterials on the mechanical properties of the composite, it paves the way for future research in optimizing composite materials and promoting sustainable construction practices.

The paper “Flexible Ultra-High Performance Reinforced Cementitious Composite Plates Based on Multiscale Fibrous Reinforcements,” is authored by Peizhao Zhou, Peng Feng. Full text of the open access paper: https://doi.org/10.1016/j.eng.2025.02.005. For more information about Engineering, visit the website at https://www.sciencedirect.com/journal/engineering.

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Journal

Engineering

DOI

10.1016/j.eng.2025.02.005 

Article Title

Flexible Ultra-High Performance Reinforced Cementitious Composite Plates Based on Multiscale Fibrous Reinforcements

 

China’s EV ultrafast charging stations: Challenges, solutions, and costs

Higher Education Press

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Overall framework for fast and ultrafast charging station analysis.

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Credit: Yang Zhao et al.

A new study published in Engineering delves into the future of ultrafast charging stations for electric vehicles (EVs) in China, exploring charging patterns, grid impacts, solutions, and upgrade costs. As the global EV market continues to expand rapidly, with China leading the way in EV adoption, understanding these aspects is crucial for sustainable development.

The research team, led by Yang Zhao, Xinyu Chen and Michael B. McElroy, analyzed real-world charging data from over 15,000 EVs at fast-charging stations across ten districts in Beijing. They established scenarios for current and future EV specifications and charging parameters, considering factors such as charging power, battery energy, and charging times.

One of the key findings is related to the impact of increased EV charging power on station loads. Contrary to the common assumption that doubling charging power would double the station load, the study shows that this is not the case. Larger stations with more chargers experience a relatively modest peak power increase of less than 30% when fast-charging power is doubled. This is because shorter charging sessions are less likely to overlap. For example, in the simulations, as the maximum EV charging power increased tenfold from scenarios S1 to S7, the peak load at the airport charging station increased by only a factor of 4.90.

The researchers also investigated two generalized solutions to address the issue of insufficient power capacity at charging stations: a dynamic waiting strategy and the deployment of energy storage. The dynamic waiting strategy can effectively decrease peak loads by delaying some charging sessions. For instance, at the airport EV charging station, with a total power capacity of 120 kW times the charger number, it can satisfy ultrafast charging demands from S1 to S7 using only this strategy, with a reasonable increase in waiting times.

Regarding energy storage, it can buffer peak loads, but the cost is a major consideration. The unit cost of lithium-ion battery energy storage is approximately 4 times higher than that of pad-mounted distribution transformers in China. However, energy storage has its advantages, such as not requiring grid capacity expansion and enabling more flexible installation.

When it comes to upgrade costs, the study identified chargers and distribution transformers as the main expenses. Comparing different upgrade strategies, the research provides valuable insights for policymakers and industry players. The results suggest that deploying large ultrafast charging stations with chargers between 350–550 kW in high-demand regions could be a viable solution to meet the surging charging demands of EVs in China. This research offers a comprehensive understanding of the future of EV ultrafast charging stations in China, which will contribute to more informed decision-making in charging infrastructure planning and grid management.

The paper “Future Ultrafast Charging Stations for Electric Vehicles in China: Charging Patterns, Grid Impacts and Solutions, and Upgrade Costs,” authored by Yang Zhao, Xinyu Chen, Peng Liu, Chris P. Nielsen, Michael B. McElroy. Full text of the open access paper: https://doi.org/10.1016/j.eng.2025.01.015. For more information about Engineering, visit the website at https://www.sciencedirect.com/journal/engineering.

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Journal

Engineering

DOI

10.1016/j.eng.2025.01.015 

Article Title

Future Ultrafast Charging Stations for Electric Vehicles in China: Charging Patterns, Grid Impacts and Solutions, and Upgrade Costs