of all...just what is a chloramine? And why am I drinking it? More importantly...will
it change the taste of my water? In regards to the taste, it's a common
thought that you likely won't notice any change. However, all the above
are great questions.
Chloramines have been used in the U.S. for drinking water disinfection
for over 70 years. Chloramine use was prevalent in the 1930’s (Spaulding
1929, Braidech 1931, Lyles 1931, Goehring 1931, and Ely 1933). A nationwide
survey conducted in 1938 showed that 16 percent of municipal utilities
used chloramines at some point in their treatment process (AWWA 1941).
Chloramine use declined during WWII because of the inability to obtain
ammonia (White 1986), and by 1959, the number of utilities using chloramines
had decreased to 6 percent (Baker 1959). By the early 1960’s, chloramine
use had dropped to less than 3 percent (Durfor and Becker 1962).
the early 1970s, researchers discovered that halogenated organics were
formed during chlorination (Rook 1974, Bellar and Lichtenberg 1974). Subsequent
toxicological studies classified some of these disinfection byproducts
(DBPs) as possible human carcinogens (Kimura Ebert and Dodge 1971, Page,
Harris, and Epstein 1976, Kuzma, Kuzma, and Buncher 1977). There has been
resurgence of interest in chloramination over the last 30 years as utilities
seek a means to provide secondary disinfection while limiting disinfection
byproduct (DBP) formation. In 1979, EPA published the first regulations
limiting DBPs in the National Interim Primary Drinking Water Regulations
for Control of Trihalomethanes. A maximum contaminant level (MCL) for
total trihalomethanes (TTHMs) was set at 100 µg/L.
researchers began to evaluate alternative disinfectants to limit DBP formation,
it was discovered that chloramines resulted in significantly less TTHM
formation than free chlorine (Brodtman and Russo 1979 and Norman, Harms,
and Looyenga 1980). Laboratory results, in which chloramines required
much higher concentrations and longer contact time to achieve microbiological
inaction levels comparable to chlorine, led EPA to impose a ban on use
of chloramines (National Interim Primary Drinking Water Regulations, USEPA
1978). Field results, however, indicated a much higher chloramine biocidal
efficiency than predicted by laboratory research (Shull 1981, Brodtman
and Russo 1979, and Mitcham, Shelley, and Wheadon 1983).
successful applications of chloramination in field tests convinced EPA
to rescind the ban a year later (USEPA 1979). The discrepancy between
lab and field results for chloramine biocidal efficiency has been theorized
to result from the relative resistance of in situ and laboratory grown
organisms, the method of chloramine application (lab tests were typically
conducted with preformed chloramines), and the criteria for evaluating
the effectiveness of a disinfectant.
regards to the taste chloramines may or may not leave in your drinking
water, most consumers will not notice a change in water taste by switching
from chlorine to chloramines for water disinfection. However, in surface
waters that contain phenol, chlorine oxidation can produce chlorophenol
as a byproduct. This chemical, which can impart taste and odor problems
in drinking water, is not formed by chloramines. Some of the odor complaints
in drinking water that people associate with chlorine are actually due
to chlorine byproducts generated by incomplete oxidation.