HIGH RATE FLOATING MEDIUM FLOCCULATION-FILTRATION WITH IN-LINE POLYSILICATO-IRON (PSI) ADDITION

Polymer addition in floating medium flocculation-filtration system. Firstly, the process is presented and shown that high loading rate until 60 m/h is useful. Polysilicato iron (1.5 mg/L) and organic polymer (0.4-0.6 mg/l) were used to improve the floc formation. With the system, 90 to 95 % of turbidity (initial analysis 5.4 NTU) was removed for a filtration rate close to 30 m/h. Frequent but short backwash (1 min every 90 min) allow to maintain good effluent quality (less than 1 NTU turbidity).