The Multi-grade Sand Filter is a depth filter that makes use of coarse and fine media mixed together in a fixed proportion. This arrangement produces a filter bed with adequate pore dimensions for retaining both large and small suspended particles.
This filter performs at a substantially higher specific flow rate than conventional filters. Specific flow rates of 15-30m/h have been successfully obtained for treating water containing 25-50ppm suspended solids respectively to produce a filtrate with less than 5ppm.
Various variants available according to requirements for ion removal, dechlorination, odour removal and colour removal.