Answer:
In the sewage treatment process, one of the most important steps is the separation of liquids and solids, in this process, we can give several examples of processes:
1. Water-Oil Separation - oils are used to receive effluent and oil and grease contaminated water from maintenance areas, vehicle and machine washing and mechanical workshops. Water - oil separators employ physical methods and work by density, using the tendency of oil to float in water;
2. Decanting and Decanters - Decanting is a physical method of separation such as filtration, coagulation, flocculation, flotation, etc., working by density. Sludge settlers use lower settling rates;
3. Flotation - Flotation in effluent and water treatment separates liquids from solids with clouds of air microbubbles that drag suspended impurities to the surface facilitating removal;
4. Drag Column - Removal of Contaminant Gases - The removal processes of Ammonia, VOC's, Radon, Carbonic Gas (CO2) and BTEX and mainly water nitrogen are usually based on biological oxidation (nitrification-denitrification);
5. Water filters: Sand, Coal, Zeolites, MnO2, Anthracite, etc. - The waters contain salts, suspended solids, microorganisms and debris that must be removed. Filters generally remove particles and improve color, odor, and taste.