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Views: 222 Author: Carie Publish Time: 2025-03-11 Origin: Site
Content Menu
● Introduction to Microbial Wastewater Treatment
● Key Bacterial Groups in Sewage Treatment
● Advanced Microbial Applications
>> A. Pathogen Control Challenges
>> B. Engineered Bacteria for Emerging Contaminants
>> 1. Antibiotic Resistance Spread
● FAQ
>> 1. Can sewage bacteria produce renewable energy?
>> 2. Why do some pathogens survive treatment?
>> 3. How do bacteria remove nitrogen?
>> 4. Are engineered bacteria safe for release?
>> 5. What happens to dead bacterial biomass?
● Citation
Sewage treatment relies heavily on microbial activity to purify wastewater and mitigate environmental harm. This article explores the bacterial species involved, their roles in different treatment stages, emerging challenges, and cutting-edge innovations in microbial engineering.
Modern sewage treatment combines physical, chemical, biological processes to remove contaminants. Biological treatment, responsible for ~90% of organic matter removal[8], utilizes bacteria to degrade pollutants. These microorganisms transform harmful substances into harmless byproducts like CO₂, methane, and water.
Requiring oxygen, these bacteria dominate activated sludge systems and trickling filters:
- Nitrosomonas and Nitrobacter: Convert ammonia to nitrate (nitrification)[8].
- Zoogloea: Forms flocs that settle sludge[1].
- Pseudomonas: Degrades hydrocarbons and synthetic chemicals[6].
Mechanism: Aerobes oxidize organic matter via enzymatic reactions:
C6H12O6+6O2→6CO2+6H2O+Energy [8]
Thriving in oxygen-free environments, they drive sludge digestion and methane production:
- Methanosarcina and Methanosaeta: Archaea converting acetate to methane[4].
- Clostridium: Breaks down complex organics into fatty acids[4].
- Desulfuromonas: Reduces sulfates, controlling odor[4].
Advantages:
- 40–60% reduction in sludge volume[1].
- Methane production for energy (yield: 0.35 m³/kg COD removed)[4].
Adapt to aerobic/anaerobic conditions, enhancing system resilience:
- Thauera: Degrades aromatic compounds under low oxygen[4].
- Georgenia: Removes phosphorus in alternating conditions[4].
- Antibiotic-resistant genes (ARGs) persist in treated sludge. A 2024 study showed anaerobic digestion reduces ARGs by 50–70%, but E. coli strains with microbial "Kevlar" traits survive chlorination[3][7].
- Heat-resistant Clostridium perfringens: Survives 60°C, indicating need for tertiary disinfection[4].
- PET-degrading bacteria: University of Waterloo engineers modified Pseudomonas spp. to break down microplastics via horizontal gene transfer[5].
- Heavy metal bioaccumulation: Rhizobium strains sequester lead (Pb⊃2;⁺) and cadmium (Cd⊃2;⁺) at 85–92% efficiency[2].
| Stage | Process | Key Bacteria | Output |
|---|---|---|---|
| Primary | Sedimentation | N/A | 50–70% solids removed8 |
| Secondary | Activated sludge/aeration | Nitrosomonas, Zoogloea | 85% BOD reduction8 |
| Tertiary | Anaerobic digestion | Methanosarcina, Clostridium | Biogas (60% CH₄)4 |
| Advanced | Biofiltration/Disinfection | Engineered Pseudomonas5 | Microplastic removal (~70%) |
- ARGs in E. coli and Klebsiella increase 3-fold post-treatment[7].
- Solution: UV/chlorine combos reduce resistant strains by 99.9%[3].
- PET fragments (<1 mm) evade conventional filters.
- Innovation: Synthetic microbial consortia digest 80% PET in 48 hrs[5].
- Methane from anaerobic digestion offsets 30–50% of plant energy use[4].
Diagram: Circular economy model integrating biogas and recycled water.
Bacteria serve as nature's wastewater engineers, enabling cost-effective pollutant removal. However, evolving challenges like ARGs and microplastics demand engineered solutions. Future systems will likely combine natural microbes with synthetic biology to achieve UN Sustainable Development Goal 6 (clean water for all).
Yes. Anaerobic species like *Methanosarcina* generate methane, which can power treatment plants[4].
Resistant E. coli strains evolve protective biofilms and heat-shock proteins, evading disinfection[7].
Nitrosomonas oxidizes NH₃ to NO₂⁻, followed by Nitrobacter converting NO₂⁻ to NO₃⁻. Denitrifiers then reduce NO₃⁻ to N₂ gas[8].
Current designs use containment strategies like auxotrophy to prevent environmental spread[5].
Digested sludge (biosolids) is heat-dried and repurposed as fertilizer[8].
[1] https://aosts.com/role-microbes-microorganisms-used-wastewater-sewage-treatment/
[2] https://pmc.ncbi.nlm.nih.gov/articles/PMC10376923/
[3] https://www.awa.asn.au/resources/latest-news/new-research-tackles-antibiotic-resistant-genes-in-wastewater-treatment-plants
[4] https://pmc.ncbi.nlm.nih.gov/articles/PMC6002452/
[5] https://uwaterloo.ca/news/removing-microplastics-engineered-bacteria
[6] https://pmc.ncbi.nlm.nih.gov/articles/PMC8540054/
[7] https://www.ualberta.ca/en/folio/2021/05/some-e-coli-bacteria-not-only-survive-but-thrive-in-wastewater-treatment-plants-study.html
[8] https://www3.epa.gov/npdes/pubs/bastre.pdf
[9] https://aquacycl.com/blog/13-new-technologies-that-are-changing-the-wastewater-treatment-landscape/
[10] https://pmc.ncbi.nlm.nih.gov/articles/PMC10968575/
