Stacked Rapid Sand Filtration Backwash
Fall 2014
The goal of StaRS Backwash is to determine the sand grain sizes and distribution for the most efficient and effective backwash in the stacked rapid sand filters. The proper amount of fluidization must be determined for efficient backwash. A expansion ratio of 1.5 is the current standard for the sand bed during fluidization. A sand size ratio below 1.5 is suggested for minimal segregation during backwash. AguaClara plants currently use a backwash velocity of 11 mm/s, so this is the experimental backwash velocity we will use. Different sand grain sizes will be tested in a small scale sand filter for proper fluidization and efficient backwashing.