Parameters that influence the dewatering abilities of sludge
Several parameters concerning the sludge will influence its ability to dewater easily. Amongst these, the main ones are:
The incorporation of the flocculant. The higher the concentration of the sludge, the harder it is to mix in a viscous solution of flocculant (even at low flocculant concentrations). Solutions to this problem are: post-dilution of the flocculant, injecting the flocculant upstream, multiple injection points of the flocculant, use an on-line mixer.
The consumption of flocculant. The higher the concentration of the sludge, the lower the consumption of flocculant. This is true only if the incorporation is correctly done.
The higher the VS, the more difficult the dewatering. The dryness achieved will be low, the mechanical properties will be low and the flocculant consumption will be high. When the VS of the sludge is high, it is recommended to add a thickening step in the process in order to achieve a better dewatering.