Enhancement of performance of filter using deep bed mono media with alum as filer aid

Abstract

The use of filter aid to improve the performance of conventional rapid sand filter (RSF) is a relatively new development in drinking water treatment. Different advantages claimed by such use of filter aid includes reduction in ripening period, higher turbidity removal as well as relatively stable effluent quality while the limitations includes the reduction in filter rate as well as reduction in filter run. To overcome these limitations, the attempt is made to devise the RSF by increasing the effective size (around 0.85mm) and lowering the coefficient of uniformity of media (around 1.2) with use of alum solution as a filter aid. The study is conducted at one of the water treatment plant at Ichalkaranji, Maharashtra by installing a pilot scale model. The results are very encouraging. High turbidity removal, extended filter run and net reduced backwashing requirement are the prominent features observed.