What Happens in the Tank?
- Anaerobic bacteria begin to break down some wastes in the tank.
- Wastewater contains suspended solids.
- Heavy solids settle out and form sludge on the bottom of the tank.
- Light solids float to the top of the liquid layer and form scum.
- A liquid layer (called effluent) remains in the middle.
- Effluent moves out to the drainfield for further treatment.