| The use of geotextile fabrics in slow sand filtration is a recent phenomenon which is still being investigated to determine their optimum usage. A number of studies have been conducted to establish how synthetic or natural fabrics improve operation of slow sand filters. Results of these studies seem to indicate varying levels of performance improvements based on several factors. This study was conducted to establish reasons for varying performance improvements and try to find ways of how a particular fabric and its layer configuration could be used for optimum filtration performance. The study used raw water from Ellicott Creek. The results suggest a complexity in determining fabric thickness and layer configuration due to varying raw water characteristics in time and space, sand packing, and geotextile fabric characteristics that all have an impact on filtration performance. The varying results lead to a conclusion that the choice of a particular fabric to use in a particular slow sand filtration process may have to be determined through laboratory tests prior to use in actual filters. |
