Aeration Tank

Preliminary treatment:
Bar screens large debris like rags,paper and leaves from the influent water.
Primary treatment:
Scum floats and sludge settles at the bottom of the primary setting tank.Skimmers remove scum from the surfase of the water and Scrapers remove sludge from the tank bottom both are sent on to the solids handiling process.
Secondary treatement:
It is a biological process where primary effluent is pumped to aeration tanks where oxygen is added to encourage growth of desirable micro-organisms.Micro-organisms consumes suspended and dissolved organic material present in waste water,in the process they produce more bacteria.