Fig. 5: Sludge volumes generated after 3 min of settling (SV3min) in softening with ballasted flocculation (SBF) with different dosages of various polymer flocculants (color coded) (n = 3, means ± standard deviations).

Six types of anionic polymers (AP199, AP335B, AP825B, AP335PWS, AP120PWS, and AP410PWS) and one nonionic polymer (NP800PWS) were tested.