At the core of this breakthrough is the integration of cold plasma technology with a microbubble system that intensifies plasma-liquid interactions. Cold plasma, an ionized gas at near-ambient temperatures, is known for generating reactive species capable of breaking down pollutants and transforming chemical compounds. By introducing electrified microbubbles containing these reactive nitrogen and oxygen species into the wastewater, the MB-CPA system enhances the degradation of organic contaminants while enriching the aqueous environment with bioavailable nitrogen forms essential for plant nutrition.

Professor Xuehua Zhang, the corresponding author of the study, emphasizes the urgency of such innovations. Modern agriculture remains heavily reliant on synthetic fertilizers and vast amounts of freshwater, resources whose sustainability is increasingly challenged. “Every day, we discard enormous volumes of nutrient-rich wastewater simply because of its high organic load,” she explains. “Our technology addresses several challenges simultaneously—wastewater treatment, nutrient recycling, and sustainable agriculture—offering a truly integrated solution.”

Unlike conventional wastewater treatment processes that often focus solely on contaminant removal, the MB-CPA technology performs dual functions. It not only purifies the wastewater by breaking down organic pollutants but also imbues the treated liquid with nitrate species, a form of nitrogen readily absorbed by plants. This conversion is facilitated through oxidative reactive nitrogen and oxygen species produced during the plasma activation, which fix nitrogen into bioavailable compounds, effectively transforming a pollutant into a crucial agricultural input.

The system was tested using medium-strength wastewater sourced from the malting industry, a sector known for generating effluents with significant organic content. Results demonstrated marked reductions in organic load and suspended solids, alongside a substantial increase in nitrate concentration, making the treated water ideally suited for hydroponic cultivation. The integration of the MB-CPA system with a hydroponic framework revealed impressive agronomic outcomes, such as accelerated germination rates and biomass accumulation, notably in garlic sprouts, which nearly doubled when grown with the plasma-treated nutrient solution.

Beyond enhanced biomass, the treated water was shown to influence the nutritional profile of the crops. Elevated sulfur content was detected in plants irrigated with the MB-CPA processed wastewater, underscoring the technology’s potential to enrich nutrient profiles and promote plant health. This suggests broader implications for crop quality and nutritional value, which could contribute positively to food security and human health.

One of the technology’s defining advantages is its automation and energy efficiency. The MB-CPA system requires minimal human intervention, making it less labor-intensive and more amenable to deployment in varied agricultural contexts. Importantly, its operation is compatible with renewable energy sources, including solar and wind, supporting the system’s scalability and sustainability. This convergence of automated wastewater treatment and sustainable energy use aligns well with global efforts to reduce agriculture’s carbon footprint and promote green practices.

The potential applications of MB-CPA extend beyond malting industry wastewater. The research team envisions adapting this technology across a range of wastewater streams from food processing and other industrial sectors, thereby unlocking vast quantities of valuable nutrients currently lost as waste. By converting these effluents into hydroponic fertigation media, the approach fosters a circular economy model where waste is repurposed for productive use rather than disposed of, mitigating environmental pollution and resource depletion.

The significance of this work must also be viewed within the broader context of global water scarcity and agricultural intensification. With arable land shrinking and freshwater resources under stress, novel water reclamation techniques that also supply essential nutrients become indispensable. MB-CPA elegantly addresses both issues concurrently, offering farmers a resilient approach to crop production that minimizes reliance on external inputs, reduces freshwater withdrawals, and closes the loop on nutrient cycles.

While the technology is still in the experimental stage, its promising results have catalyzed plans for scaling up and field validation. Integration with full-scale hydroponic farms and diverse crop species will be critical to assess broader applicability and economic feasibility. Furthermore, ongoing optimization of plasma parameters and microbubble dynamics is expected to enhance treatment efficacy, nutrient profiles, and energy consumption metrics.

This pioneering approach exemplifies how interdisciplinary innovations—spanning chemical engineering, environmental science, and agronomy—can catalyze sustainable transformations in food production systems. By harnessing plasma science and microbubble technology to address pressing environmental challenges, the University of Alberta team sets a new benchmark for eco-engineered precision agriculture. Their work opens new horizons where wastewater ceases to be a disposal concern and becomes a cornerstone resource for the future of farming.

Contact the author: Xuehua Zhang, Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Canada, xuehua.zhang@ualberta.ca

Subject of Research: Not applicable

Article Title: Microbubble-enhanced cold plasma activation of food-industry wastewater for valorization and hydroponic crop production

Web References: http://dx.doi.org/10.1016/j.gce.2026.03.001

Image Credits: Deepak Panchal, University of Alberta

Keywords: Biochemical engineering, Pollution, Hydrology, Plant sciences, Food science, Sustainable agriculture, Wastewater, Biotechnology

Ceramic membranes have long served critical roles in treating industrial wastewater, facilitating seawater desalination, and producing ultrapure water essential for semiconductor manufacturing. Their durability under harsh chemical and thermal conditions makes them invaluable for these demanding applications. However, existing manufacturing methods involve complex multi-layer coating processes followed by high-temperature sintering typically above 1300°C, resulting in excessive energy consumption and undesirable surface defects. These defects, specifically microcracks on the membrane’s separation layer, compromise filtration accuracy and reduce operational lifespan, leading to increased costs and inefficiencies.

To overcome these technical barriers, the research team pioneered a Mutual Doping methodology, whereby particles from different layers are finely mixed to reinforce bonding and densification within the membrane matrix. This approach is coupled with a Co-sintering process, wherein all membrane layers are fired simultaneously, thereby reducing fabrication steps and cutting the sintering temperature to around 1000°C. This temperature reduction not only offers substantial energy savings but also promotes the formation of a uniformly dense ceramic structure. Particularly notable is the achievement of an ultra-flat membrane surface with surface roughness halved from 24.49 nm to a remarkable 11.74 nm, a milestone previously unattainable with conventional sequential layering and sintering methods.

The exceptionally smooth and crack-free ceramic substrate formed through this refined process provides an ideal platform for applying a self-developed eco-friendly aqueous zirconia (ZrO₂) sol coating. This coating serves as the active nanofiltration layer, leveraging the combined mechanisms of size-exclusion due to well-controlled nanoscale pores and electrostatic repulsion to selectively filter contaminants. Impressively, this membrane demonstrates the ability to remove over 99.8% of dye molecules from dye-laden wastewater while allowing monovalent salt ions to permeate, even at low operational pressures as gentle as 2 bar—pressures comparable to typical household tap water.

Operating efficiently at such low pressures marks a significant departure from traditional ceramic nanofiltration membranes that generally require pressures near 10 bar to function effectively. Lowering the operational pressure directly translates into reduced energy requirements, substantially decreasing the carbon footprint of large-scale water treatment facilities. Additionally, the membrane’s high water permeability and robust chemical stability extend its functional lifetime and enhance flux recovery capabilities. These factors collectively elevate the economic feasibility of deploying ceramic membranes on an industrial scale, supporting both sustainability goals and cost-effectiveness.

This advanced membrane technology transcends mere contaminant removal by enabling refined separation and resource recovery, expanding the functional horizons of water treatment systems. The ability to selectively separate dyes from ions addresses a critical limitation in current commercial membrane technologies, opening new pathways for treating complex industrial effluents and recycling valuable resources. Moreover, the integration of materials science innovation with streamlined manufacturing underscores the potential of these membranes to meet increasingly stringent environmental regulations worldwide.

From a manufacturing perspective, the research introduces a paradigm shift through its emphasis on reducing process complexity without sacrificing membrane integrity. The combination of mutual doping and co-sintering not only simplifies the fabrication workflow but also establishes a reproducible pathway for producing defect-minimized ceramic membranes with consistent performance. This positions the technology favorably for scaling up to industrial production volumes.

The implications of this research are especially significant for sectors demanding ultra-pure water, such as semiconductor fabrication, where membrane reliability and precision filtration are paramount. By offering a technically advanced yet energy-efficient solution, this ceramic membrane technology promises to curb dependency on imported materials, foster domestic innovation, and bolster national competitiveness in the high-value membrane market traditionally dominated by a few advanced countries.

Ongoing efforts by the KIMS research team focus on translating laboratory-scale innovations to large-area membrane fabrication and mass production. The team has secured patents in both domestic and international jurisdictions to protect the core technologies, underscoring a commitment to commercializing this breakthrough. Plans are underway to validate the technology’s industrial applicability through pilot-scale demonstrations and to facilitate technology transfer to relevant industries poised to integrate this environmentally responsible water treatment solution.

Dr. Hong-Ju Lee emphasized the dual achievement of securing material technologies operable at low pressures and refining manufacturing processes to a near-defect-free state as foundational to future advances. This research, supported by the National Research Foundation of Korea and the Korea Institute for Advancement of Technology, exemplifies the synergistic potential of multidisciplinary collaboration in addressing global water challenges through innovative materials science.

As water scarcity and pollution concerns escalate globally, the ability to deploy highly efficient, durable, and energy-conserving filtration membranes is of paramount importance. The KIMS team’s innovations represent a significant leap towards environmentally sustainable water management technologies that balance performance with economic and ecological considerations. This advancement sets a benchmark for future research in ceramic membrane fabrication, heralding a new era of water treatment capabilities capable of addressing diverse industrial and environmental needs.

By harnessing the synergy between novel material compositions and process engineering, this research exemplifies the transformative potential inherent in next-generation nanomaterials development. The resultant membranes not only offer immediate improvements in water treatment efficacy but also lay the groundwork for broader applications in resource recovery and environmental remediation in the years to come.

Subject of Research: Development of ultra-flat, defect-free ceramic nanofiltration membranes with low-pressure operability through innovative mutual doping and co-sintering fabrication technologies.

Article Title: Controlling substrate surface roughness via co-sintering of MF/UF-range sublayers ceramic membranes for high-integrity mesoporous top-layer coatings

News Publication Date: 1-Feb-2026

Web References: DOI Link

Image Credits: Korea Institute of Materials Science (KIMS)

Keywords

Ceramic Membranes, Nanofiltration, Water Treatment, Mutual Doping, Co-sintering, Zirconia Sol, Surface Roughness, Low-Pressure Filtration, Industrial Wastewater, Process Innovation, Energy Efficiency, Membrane Fabrication