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1. MET – From Laboratory Research to Industrial Breakthrough
A recent review published in Nature Reviews Clean Technology (February 2025) highlights that MET leverages the extracellular electron transfer ability of microorganisms not only to degrade organic pollutants in wastewater, but also to recover electricity, hydrogen, or capture CO₂ by converting carbon into calcite, providing dual benefits in treatment and energy generation.
2. Diverse Applications & High Efficiency
According to Frontiers in Sustainability, MET has been successfully applied to domestic, livestock, industrial, and hospital wastewater, achieving COD removal efficiencies of over 80% from cleanroom-level experiments to pilot scale.
In petrochemical wastewater applications, MET not only removes toxic compounds but also converts them into valuable chemicals, reducing energy costs compared to traditional technologies.
3. Creative Integration: MET + Constructed Wetlands (METland)
A standout innovation is the integration of MET with constructed wetlands, known as METland or CW-MFC/MEC. These systems:
Utilize electroactive bacteria in saturated soil environments to effectively remove micropollutants such as pharmaceuticals and chemicals, while reducing ammonium and COD.
Deliver high treatment performance with a small footprint, ideal for rural, industrial, or hospital wastewater treatment.
4. MET – A “Three-Without” Breakthrough Solution
Research and real-world applications in Vietnam emphasize that MET operates without electricity, chemicals, or filtration cartridges, and does not produce secondary sludge. Thanks to pressure-driven mechanical filtration, the system self-develops a treatment membrane that retains minerals while maintaining safety for human health.
5. Potential for Resource and Energy Recovery
Phosphate: Can be recovered as struvite in MEC systems, enabling reuse as fertilizer (according to environmental journals).
Carbon dioxide: A specific MET variant (MECC) can capture CO₂ and simultaneously produce hydrogen and calcite, making it carbon-negative.
Methane & Hydrogen: MET combined with anaerobic fermentation (AD-MET) has shown improved degradation of propionate and production of CH₄, though energy input must be balanced across the system.
6. Remaining Challenges
Many MET studies remain at the pilot or lab scale, requiring full-scale validation to assess capital investment and life cycle costs (LCA) (according to environmental journals).
System configurations—such as electrode design, materials, circuitry, and bioreactor layout—still need to be optimized according to specific wastewater sources and treatment goals.
