Environmental Engineering Reference
In-Depth Information
The USEPA Science Advisory Board ranks pollutants in drinking water as
one of the highest health risks meriting the Agency's attention because of
large-scale population exposure to contaminants, including lead, disinfec-
tants and disinfection byproducts (DBPs), and disease-causing organisms.
Disinfectants are used by virtually all surface water systems in the United
States and by an unknown percentage of systems that rely on groundwater.
For nearly a century, chlorine has been the most widely used and most cost-
effective disinfectant; however, disinfection treatments can produce a wide
variety of byproducts, many of which have been shown to cause cancer or
other toxic effects. Recently, concern has been raised over water quality dete-
rioration, a problem that can grow dramatically during distribution unless
systems are properly designed and operated. Disinfection is an integral part
of water treatment, but filtration prior to disinfection is necessary to reduce
pathogen levels and make disinfection more reliable by removing turbidity
and other interfering constituents.
To solve the disinfectant and disinfection byproducts problem, we need
innovative upgrades for the existing techniques, as well as new approaches
to address these problems. Areas of interest include
• Alternatives to chlorine disinfection for removing pathogenic micro-
organisms, including innovative applications of ultraviolet (UV)
radiation and processes that improve overall effectiveness while
using reduced amounts of disinfectant
• Development of innovative unit processes, particularly for small
systems, for removal of organic and inorganic contaminants (such
as arsenic), particulates, and pathogens, such as cyst-like organ-
isms and emerging pathogens such as caliciviruses, microsplorida
(septata and enterocytozoan), hepatitis A virus,
Mycobacterium
avium
-intracellulare complex (MAC),
Helicobacter pylori
,
Lengioneela
pneumophilar
, adenovirus 40/41/1-39, and
Toxoplasma gondii
• Development of eficient, cost-effective treatment processes for
removing disinfection byproduct precursors (e.g., trihalomethanes,
haloacetic acids), for ozonation (bromate, aldehydes), for chlorination
(chloropicrin, haloacetonitriles), and for chloramination (organic
chloramines, cyanogen chloride)
• Improved methods for controlling pathogens through coagulation/
settling, filtration, or other cost-effective means
• Drinking water contamination control between the treatment plant
and the user, especially considering potential chemical leaching
from distribution system materials and surfaces (e.g., lead, cop-
per, iron, and other pipe materials; protective coatings) as a result
of instability, interaction with microorganisms, disinfection agents,
and water treatment chemicals
