A Perspective of Riverbank Filtration

TLDR

Riverbank filtration uses wells along riverbanks to divert river water into aquifers, attenuating contaminants through filtration, microbial degradation, sorption, and dilution, and has been employed in Europe since the 1870s while gaining renewed U.S. interest for cost‑effective drinking‑water pretreatment and regulatory compliance.

Abstract

Riverbank filtration (RBF) is a process in which pumping wells located along riverbanks induce a portion of the river water to flow toward the wells. During RBF, which has many similarities to slow‐sand filtration, river water contaminants are attenuated from a combination of processes such as filtration, microbial degradation, sorption to sediments and aquifer sand, and dilution with background groundwater. RBF systems have been operating in Europe since the 1870s. In the United States, there has been renewed interest among large‐ to medium‐sized utilities to use it as a mechanism of water production to reduce treatment costs and to meet regulations on pathogens, disinfection byproducts, and other contaminants under the Surface Water Treatment Rule. Although filtrate water quality from RBF systems can vary based on river conditions, it is possible that appropriately designed systems can serve as pretreatment for drinking water, and at the same time, the utility can receive log‐removal credits for pathogens and particles. In addition, RBF can be used as a pretreatment for membrane filtration. In the United States, a knowledge gap exists on the benefits and limitations of using RBF. This paper addresses those gaps, outlining the benefits and limitations of the process. It also illustrates that RBF can be a viable alternative to surface water at suitable sites.