There are two basic principles:
- Biological treatment and
- Chemical treatment
The two categories are often combined.
Primary treatment, removal of particles:
- Sand and Grit removal
- Pre sedimentation
Biological treatment (secondary treatment)
- Biofilm processes (MBBR, MBR).
- Activated sludge processes (oxidation ditch, SBR).
- Activated sludge processes for removal of Nitrogen and Phosphorus.
Typical processes combinations are illustrated as: