Nội dung
1. What is MET Technology?
MET (Microbial Electrochemical Technologies) is a wastewater treatment technology that utilizes electroactive microorganisms in combination with electrodes to:
- Degrade organic matter in wastewater.
- Transfer electrons from microbes to electrodes.
- Generate electricity, hydrogen, or valuable chemical products such as acetate, methane, etc.
2. Fundamental Principles of MET
- Electrodes (anode – cathode): Microbes at the anode decompose organic substances and release electrons.
- Electron transfer: Electrons are transported via ion exchange membranes or salt bridges to the cathode, where reduction reactions occur.
Various outcomes:
- MFC (Microbial Fuel Cell): Generates electricity – low power, suitable for powering small devices.
- MEC (Microbial Electrolysis Cell): Produces hydrogen (H₂) or methane (CH₄) through electrochemical processes.
- MES (Microbial Electrosynthesis): Synthesizes valuable chemicals.
- Microbial Desalination Cell: Simultaneously treats wastewater and desalinates water.
3. Applications of MET in Wastewater Treatment
| Area of Application | Main Purpose |
|---|---|
| Domestic, industrial, and medical wastewater treatment | Reduce BOD, COD, pathogens, and heavy metals |
| Desalination | Combines wastewater treatment with salt removal |
| Energy and chemical recovery | Produces electricity, hydrogen, methane, acetate for circular economy |
| Advanced applications | BOD/COD sensors, regeneration of detoxifying agents (e.g. Cr(VI), nitrate) |
4. Advantages and Disadvantages of MET
✅ Advantages:
- Energy-saving: no need for aeration systems
- Recovery of valuable products: electricity, H₂, CH₄, acetate
- Reduced sludge production: less biological sludge than aerobic systems
- Environmentally friendly
⚠️ Limitations:
- High investment cost in electrodes, membranes, and equipment
- Low efficiency when scaled up
- Complex control requirements (voltage, pH, temperature, microbial activity)
- Not yet widely applied in large-scale industrial systems
5. How is MET Different from Traditional Technologies?
- Aerobic (MBR, AAO): Requires oxygen supply, high energy consumption, and produces large amounts of sludge.
- Anaerobic (UASB): Saves energy but does not generate electricity.
- MET: Integrates treatment and energy recovery, reducing operational costs.
6. Roadmap for MET Implementation
- Study natural microbial communities (from sludge, ponds, and wastewater).
- Design electrodes and ion exchange membranes: select carbon-based materials (e.g., graphite).
- Conduct laboratory/pilot testing: determine optimal voltage, temperature, and pH.
- Scale-up: integrate MET with pre-treatment and chemical treatment systems (if needed).
- Monitoring & operation: track current flow and inlet–outlet water quality.
Comparison: MET vs. Conventional Technologies (MBR, AAO, UASB)
A comprehensive technical, economic, and operational comparison between MET and other common wastewater treatment technologies such as MBR, AAO, and UASB, showing differences in mechanism, efficiency, cost, and potential for energy/resource recovery.
