Describe the procedure involved in Sewage treatment?
The following technique is performed for the treatment of sewage waste: i) Primary Treatment- This entails physically separating suspended materials in settling tanks in order to reduce BOD. The raw sewage is routed into massive open tanks where it is subjected to anaerobic digestion to remove the solid fraction. ii) Secondary Therapy- Secondary treatment relies on microbial activity, either aerobic or anaerobic. Secondary treatment techniques include: Sand filters for filtration Process of aeration Application of oxidation ponds: After drying, the sludge that collects after secondary treatment is disposed of, and the efferent is allowed to be used for tertiary treatment. iii) Tertiary Treatment- This treatment comprises chemical treatment to eliminate inorganic chemicals as well as pathogenic microorganisms. Chlorination is the most common disinfection procedure.
