AWWA ACE70877

This powerpoint presentation begins by providing a brief overview of riverbank filtration, and the Manchester, New Hampshire, Water Works current and proposed water supply. The project goal was to assess riverbank filtration as a viable treatment and pretreatment option in terms of particulate, organic precursors and microbiological removal capabilities expressed in log removal credits for the city of Manchester. Project tasks included: background sampling to determine distinguishing water quality differences between background groundwater and river water; assess the travel time for river water to reach the RBF well and quantify the contribution of river water and groundwater to the RBF extraction water; and, estimate steady state performance. Conclusions indicate that: both groundwater dilution and subsurface filtration are important removal processes; the relative importance of subsurface filtration may be a function of RBF site and especially travel time/distance; excellent removals were observed; >2 log removal of bacteria, viruses and ASFB; possible to reduce available adsorption sites for organic carbon molecules with time under continuous operation; and, elevated salt concentrations resulted in problematic Fe and Mn issues. Includes tables, figures.