Sludge from the secondary clarifiers, which is relatively diluted, must be thickened prior to treatment.
Secondary sludge thickening is performed with the use of ten gravitational belt thickeners (GBT).
This thickening is performed by adding a polymer (flocculent).
During the thickening process, the concentration of solids increases to about 5% of the sludge.
Sludge thickening machine