Understanding the Key Differences in Wastewater Treatment
Septic systems treat wastewater using either anaerobic (without oxygen) or aerobic (with oxygen) processes. Both methods are effective, but they operate very differently and are used for different site conditions and regulatory requirements.
Anaerobic Systems
Standard, Traditional Septic Systems
Anaerobic systems rely on bacteria that thrive without oxygen. These systems are the most common type of septic system used in residential properties.
How They Work
- Wastewater flows into a septic tank.
- Anaerobic bacteria break down solids in low-oxygen conditions.
- Effluent moves to a drainfield for soil-based treatment.
Characteristics
- Lower operating cost
- No electrical components
- Simpler design and maintenance
- Requires suitable soil for final treatment
- Slower bacterial digestion compared to aerobic systems
Best For
- Standard residential homes
- Properties with adequate soil depth
- Sites without strict treatment requirements
Aerobic Systems
Advanced, Oxygen-Based Treatment Units
Aerobic systems use oxygen-rich environments to treat wastewater more aggressively. They work similarly to small municipal treatment plants.
How They Work
- Wastewater enters a treatment chamber with an aerator.
- Oxygen is introduced continuously.
- Aerobic bacteria rapidly break down solids.
- Clarified effluent may be disinfected before discharge or sent to a drainfield.
Characteristics
- Higher effluent quality
- Faster bacterial digestion
- Requires electricity and mechanical components
- Regular service and maintenance required
- Often used where soil is unsuitable or where advanced treatment is mandated
Best For
- Properties with poor or restrictive soil
- Commercial buildings or high-usage sites
- Locations requiring advanced wastewater treatment
- Systems like Norweco, Jet, Ecoflo, Eljen (hybrid), and ATUs
Key Differences (Side-by-Side)
| Feature | Anaerobic | Aerobic |
| Oxygen Use | No oxygen required | Requires continuous aeration |
| Bacterial Activity | Slower, less aggressive | Fast, highly efficient |
| Effluent Quality | Moderate | High (clearer, cleaner) |
| Drainfield Dependence | High (soil does most treatment) | Lower (system treats majority interally) |
| Maintenance | Low (pump every 3-5 years) | Medium to high (annual service) |
| Operational Cost | Low | Higher (electricity + service) |
| Best For | Standard homes with good soil | Poor soil, commercial, or high-treatment needs |
| System Complexity | Simple | Advanced, multiple chambers/components |
Summary
Anaerobic systems are traditional, low-maintenance, and cost-efficient — ideal for most homes with suitable soil.
Aerobic systems provide superior treatment for challenging sites, commercial applications, or areas with strict environmental requirements, but they require electricity, routine servicing, and more active management.