ALL ABOUT SEPTIC SYSTEMS

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A conventional septic system works by collecting wastewater from your toilets and drains. It retains solids and scum in a septic tank and pipes liquids to your septic drain field. In your drain field, bacteria break down wastewater pollutants and treated effluent returns to your property’s soil and groundwater.

That is the high-level answer. For a fuller understanding of how a conventional septic system works, we can break the wastewater treatment process into 10 steps:

1. Wastewater from your toilet (called blackwater) and your shower, bathtub, sink, washing machine, and dishwasher (called greywater) runs into a main drainage pipe that leads to your septic tank.
    
2. Solid materials sink to the bottom of your septic tank and form sludge.
    
3. Fats, oils, and greases float to the top of your septic tank and form scum.
    
4. Anaerobic bacteria (bacteria that do not need oxygen) in your septic tank feed on organic wastewater pollutants.
    
5. Liquids pass through an effluent filter near the outlet of your septic tank.
    
6. Filtered liquids flow through a pipe that leads to your septic drain field.
    
7. Perforated pipes in your drain field allow wastewater to seep into a layer of gravel.
    
8. Aerobic bacteria (bacteria that need oxygen) break down contaminants as wastewater percolates through the layer of gravel and into your native soil.
    
9. In your native soil, any remaining impurities are removed. These impurities may include harmful bacteria, parasites, viruses, and nutrients.
    
10. Treated wastewater reaches groundwater.