Observations of blanket characteristics in full-scale floc blanket clarifiers
Journal
Water Science and Technology
Journal Volume
47
Journal Issue
1
Pages
197-204
Date Issued
2003
Author(s)
Abstract
We monitored the changes in concentrations, zeta potentials, sizes and capillary suction times of the solids flocs in the clarified water from eight floc blanket clarifiers of Ping Tsan Water Works of Taiwan Water Supply Company with low (<10 NTU) and high (>100 NTU) turbidity raw water. For the former, one-stage coagulation-sedimentation treatment was adopted which yielded a rather unstable blanket. Complete washout was noticeable when the PACI dosage was insufficient. On the treatment of high-turbidity raw water, on the other hand, the Works adopted the combined treatment process, that is, the raw water was first coagulated and settled in a pre-sedimentation tank, afterwards, its effluent was coagulated again and clarified in the clarifiers. The resulting flocs could form a networked blanket that was relatively stable to the shock load in raw water turbidity.
Subjects
Blanket
Coagulation
Flocculation clarifier
Sedimentation
Stability
Type
conference paper