Riverbank Filtration for Drinking Water Supply

Riverbank filtration (RBF) is a low-cost water treatment/pretreatment technology that is used in many countries around the world for water supply. When wells are situated close to rivers or lakes and pumped, the surface water is induced to flow to these wells. During soil and aquifer passage, chemical, biological, and particulate contaminants are removed. Many European cities have been using RBF as the primary source of drinking water production for over a century. In the United States, RBF is gaining popularity owing to favorable regulatory provisions. In siting and designing RBF systems, the river hydrology and site hydrogeology must be carefully considered so that scouring and clogging are avoided and the aquifer is conductive to produce the desired amount of water. The source water should be of reasonably high quality to avoid the development of anoxic conditions, which ultimately may lead to the reduction of iron, manganese, and other redox-sensitive species. Three-dimensional computer models are increasingly being used for the placement and operation of RBF systems. The collection system can be vertical wells, horizontal collector wells, infiltration galleries, or combinations of any two or all three. Site-specific conditions, pumping needs, and the availability of treatment plants for further treatment of the filtrate dictate the type of collection system. The capital cost is tied to the type of collection system, conveyance system, and land acquisition. Numerous studies have pointed out the benefits of RBF in removing turbidity, pathogens, dissolved chemicals, natural organics (which are regarded as precursors for disinfection by-products for systems using chlorine as the disinfectant), and a whole host of micropollutants. Keywords: riverbank filtration; bank filtration; RBF; collector wells; water supply; pathogen removal; infiltration gallery; micropollutant removal