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. Includes 35 references, tables, figures.