Primary treatment

PRIMARY TREATMENT

• Primary treatment consists of removing large and suspended organic solids. This is done by sedimentation  in settling basins.
• The liquid effluent from primary effluents contains a large amount of suspended organic matter and a high BOD
• Sometimes, the preliminary treatment along with primary treatment together are classified as primary treatment
• Organic solids that are separated out in the sedimentation tanks in primary treatment are often stabilised by anaerobic decomposition in a digestion tank or are incinerated. 
• The residue is used for land-fills or as soil conditioners.