The Effect of Alum as Filter Conditioner on the Performance of Conventional Rapid Sand Filter

M H Mota,Professor, Civil Engineering, Rajarambapu Institute Of Technology, Rajararamnagar, Islampur India ,P.S Patil

doi:10.35940/ijeat.c5469.029320

M H Mota, Professor, Civil Engineering, Rajarambapu Institute Of Technology, Rajararamnagar, Islampur India + Show 1 more

Open Access

https://doi.org/10.35940/ijeat.c5469.029320

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Abstract

Filtration is a one of the most important and critical unit process followed worldwide which removes dirt particles from water. As the water quality standards are changing and becoming more stringent, the improvement in the performance of existing rapid sand filters is unavoidable. The use of filter conditioning to improve filter performance is a relatively recent development in drinking water treatment. Different advantages claimed by such use of filter aid includes lessening ripening period, superior turbidity removal and relatively stable filtrate quality. It also has limitations like reduction in filter run and comparatively higher back washing requirement. To assess the suitability of such method,under the existing conditions is of enormous importance.12 Current research explains the impact of filter media conditioning on the overall performance of conventional rapid sand filter. The study was carried out by installing a pilot plant at Ichalkaranji municipal water treatment plant. Different doses of alum as filter conditioner were tested and the comparison was made with the performance of conventional filter without filter aid. The parameters for evaluation were turbidity removal, filter run and backwash requirements. The dose of alum as filter conditioner was given as slug dose. The effect of zeta (ζ) potential change was observed to be one of the major reasons of the performance improvement, accelerating the surface removal since initial phase.

Highlights

Filtration is a unit process which physically removes suspended materials, certain amount of bacteria and viruses, which are able to pass through processes like aeration and clarification
[12] The zeta (ζ) potential of granular media, which is negative in normal cases and resulting in limited surface removal in initial phases, was changed to less negative resulting in improved surface removal [13]
The initial turbidity spike was observed as a result of discharge of remnant particles, confirming the findings of previous researches [24].The behavior of the filter was very poor in the ripening period

Summary

Introduction

Filtration is a unit process which physically removes suspended materials, certain amount of bacteria and viruses, which are able to pass through processes like aeration and clarification. The filtration using granular media in the form of rapid sand filter is supposed to be the polishing stage of the water treatment process. In developed countries different procedures have been reported to be very significant in improving overall filter performance. [12] The zeta (ζ) potential of granular media, which is negative in normal cases and resulting in limited surface removal in initial phases, was changed to less negative resulting in improved surface removal [13]. This event has created more opportunities in latter stage of filtration to remove turbidity. Because of changed zeta potential the improved bond between the particles removed from water resulted in reduction in separation and reduced the chances of possible break through because of higher head loss

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