Once used in industrial or civil processes, water contains additional substances that are noxious if released in the environment. Waste water must be therefore purified through appropriate purification plants.
The various plants are designed and built according to the load of pollutants to be disposed of. Purification processes therefore vary a lot and depend on the technology applied, the selected process, the safety margins to be achieved, the investments available, and the operating costs to be borne.
This overview clearly shows the vastness of the topics to be dealt with and, thus, the great number of possible solutions.
Purification processes are generally divided as follows:
- Physical
- Chemical
- Biological aerobi
- Biological anaerobic
- A combination of the previous types
Below is the list of the various stages that can be generally found in purification plants:
Sedimentation
Chemical coagulation;
Flotation;
Screening
Oxidation
Activated sludge aerobic process
Thickening stage
Digester
Clariflocculation
Sludge dehydration
Waste water disinfection
