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Views: 222 Author: Carie Publish Time: 2025-03-22 Origin: Site
Content Menu
● Introduction to Sewage Treatment
● The Microbial Workforce: Bacterial Types & Functions
>> Aerobic Bacteria (Oxygen-Dependent)
>> Anaerobic Bacteria (Oxygen-Free Environments)
● Advanced Microbial Engineering Techniques
>> 2. Immobilized Cell Technology
● Stage-by-Stage Bacterial Contributions
>> Primary Treatment Prep Work
>> Secondary Treatment Breakdown
>> Tertiary Treatment Enhancements
>> Singapore's NEWater Project
>> Copenhagen's BioGas Initiative
>> Antibiotic Resistance Crisis
● FAQ
>> 1. How long do bacteria take to treat sewage?
>> 2. Can sewage bacteria survive in drinking water?
>> 3. What happens to bacteria after treatment?
>> 4. Do temperature changes affect bacterial efficiency?
>> 5. Are genetically modified bacteria used?
Bacteria are the unsung heroes of modern sewage treatment systems, transforming hazardous wastewater into safe effluent through biochemical processes. This guide explores their critical roles, supported by scientific principles, real-world applications, and visual aids.
Modern sewage treatment protects ecosystems and public health by removing contaminants from wastewater. The process involves three key phases:
1. Primary Treatment: Physical removal of solids
2. Secondary Treatment: Biological degradation
3. Tertiary Treatment: Advanced purification
Dominant in activated sludge systems, these microorganisms require dissolved oxygen to decompose organic matter.
Key Species:
- Pseudomonas (hydrocarbon degradation)
- Nitrosomonas (ammonia oxidation)
- Bacillus (organic waste breakdown)
Metabolic Process:
C₆H₁₂O₆ (Glucose) + 6O₂ → 6CO₂ + 6H₂O + Energy
Thrive in sludge digesters and septic tanks, producing methane as a byproduct.
Key Applications:
- Sludge volume reduction (up to 60%)
- Biogas production (60-70% methane content)
Switch between aerobic/anaerobic modes based on environmental conditions.
Unique Advantage:
Maintain treatment efficiency during oxygen fluctuations in lagoons or intermittent aeration systems.
Modern biotechnology enhances natural bacterial capabilities through:
Introducing specialized bacterial strains to target specific pollutants:
- Dehalococcoides (chlorinated solvent breakdown)
- Geobacter (heavy metal precipitation)
Encapsulating bacteria in polymer matrices increases:
- Reaction rates by 40-60%
- Operational stability under toxic shock loads
While primarily physical, some hydrolysis occurs via:
- Clostridium (cellulose breakdown)
- Bacteroides (protein digestion)
Retention Time: 1-2 hours
Activated Sludge Process:
- Aeration tanks maintain 2-4 mg/L dissolved oxygen
- MLSS (Mixed Liquor Suspended Solids): 2,000-4,000 mg/L
- F/M Ratio (Food-to-Microorganism): 0.2-0.6 day⁻⊃1;
Trickling Filters:
Biofilms containing Zoogloea and Sphaerotilus achieve 85-95% BOD removal.
Emerging bacterial applications in advanced treatment:
1. Denitrification: Paracoccus converts nitrates to N₂ gas
2. Phosphate Removal: Acinetobacter stores polyphosphates
3. Pathogen Control: Bdellovibrio preys on harmful bacteria
Uses membrane bioreactors (MBRs) with engineered microbial consortia to achieve 99.9% pathogen removal.
Anaerobic digestors process 300,000 tons/year of sludge, generating 5.7 million m³ of biogas annually.
Wastewater plants are hotspots for ARG (Antibiotic Resistance Gene) transfer. Solutions include:
- UV/ozone pretreatment
- Biochar filtration systems
Pioneering research with Ideonella sakaiensis (PETase enzyme producer) shows 90% plastic degradation in 6 weeks.
1. AI-Optimized Microbial Consortia
Machine learning models predict optimal bacterial combinations for specific waste profiles.
2. Electroactive Bacteria
Species like Shewanella generate electricity while treating wastewater.
3. Space Applications
NASA's onboard systems use extremophiles for long-duration missions.
From basic organic breakdown to cutting-edge resource recovery, bacteria enable sustainable wastewater management. As microbial engineering advances, we're transitioning from waste treatment plants to "water resource factories" that produce clean water, energy, and raw materials.
Retention times vary:
- Aerobic systems: 4-8 hours
- Anaerobic digestors: 15-30 days
- Tertiary systems: 1-2 days
Most treatment bacteria die in clean water due to nutrient scarcity and disinfection. However, pathogenic species require rigorous tertiary treatment.
In activated sludge systems, 30-50% return to aeration tanks. Excess biomass becomes biosolids for agriculture or incineration.
Optimal ranges:
- Mesophilic: 20-45°C (common)
- Thermophilic: 45-80°C (faster but energy-intensive)
Limited to pilot projects due to regulations. Current focus is on consortia optimization rather than single GM strains.
