AWWA WQTC58986

The proposed Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR) recommends that riverbank filtration be one of several treatment tools that can be used by utilities to reduce the concentration of Cryptosporidium in surface water. To date, limited guidance exists that will provide information on how to perform treatment demonstration studies in order to obtain greater than 1.0 log credit. As with engineered filtration systems the rate of flow through porous media of the streambed and aquifer is critically important with respect to particulate removal. Flow rates must not exceed the media's ability to retain particles. Riverbank filtration demonstration studies should be performed during periods of high infiltration as determined from unit infiltration rate evaluations. Includes 9 references, table, figures.