CHARACTERISTICS PERFORMANCE OF VERTICAL UPFLOW FILTERS

Abstract

The vertical upflow filter(using plastic media by M/S Ion Exchange) is an effort to synthesise the advantages of upflow filter and pressure filter.Fine.plastic particles are used in this filter as filtering media. The plastic media gets lifted up as the raw water is passed through bottom with pressure. The efficiency of removal of turbidity is high as the raw water passes through fine media at pressure. The performance of the filter was checked with respect to filtrate quality and head loss variation. The character-istics performance were studied for coagulated and uncoagul-ated raw water at different rates of flow and turbidities. The bacteria removal efficiency of the filter was also checked at low as well as high bacterial loading. The backwash water requirement as well as the time needed for the operation were also observed. It was concluded that vertical upflow filter gives better results than the conventional filters. The filtrate quality is better and the head loss built-up is less. The length of run can be increased without getting breakthrough. The bacteria removal efficiency is almost 100 percent for low range of bacterial loading i.e. upto 300 MPN and at high range of bacterial loading the efficiency of removal is about 97'percent. The backwash water requirement ranges between 10-13 percent of the filtered water and the time vi. vii required for complete backwash operation is between 8=10 percent of the length of run. Based on the study it can be well said that the performance of the vertical upflow filter is better than that of normal gravity filters. Considering the overall performance it can be said that the vertical upflow filter is a better replacement to the rapid gravit Y sand filter.