Ozonation: Assessing Its Role in the Formation and Control of Disinfection By‐products

Abstract

An increasing number of chlorinated by‐products resulting from disinfection practices will be regulated as a result of the 1986 amendments to the Safe Drinking Water Act. Consequently, ozone is being employed more frequently for the control of trihalomethanes and other disinfection by‐products (DBPs). To evaluate the impact of ozonation on the formation and control of DBPs in drinking water, studies were conducted at four utilities. Treatment modifications were made on the process trains at each plant either at full or pilot scale to incorporate ozone in the treatment process. Samples were collected before and after ozone was added to the treatment train and were analyzed for selected DBPs. In general, treatment trains that employed ozonation followed by chloramination were the most effective in reducing trihalomethanes and other halogenated DBPs. Increases were found, however, in some compounds such as chloropicrin and aldehydes.

Formaldehyde Formation During Ozonation Of Drinking Water

“…It is important to note that free chlorine can also produce aldehydes although to a lesser extend than ozone. Large increases in aldehyde formation were reported by Lykins et al (5) and Jacangelo et al (6), whenever ozonation was followed by secondary disinfection.…”

“…Yamada and Somiya (7), by using an o- (2,3,4,5,6,-pentafluorobenzyl)-hydroxylamine (PFBOA) derivatization method were able to demonstrate the presence of low molecular weight aldehydes in ozonated surface and wastewater. Their study revealed that formaldehyde and acetaldehyde are the major carbonyl by-products present in ozonated waters.…”

“…A survey in 1990/91 of 10 North American utilities that used ozonation at pilot or full scale operations also indicated that aldehydes, especially formaldehyde, acetaldehyde, glyoxal and methylglyoxal, have formed at all the utilities surveyed (4,8). Many others also reported that formaldehyde, acetaldehyde, glyoxal, and methylglyoxal were the predominant aldehydes that exist on a weight basis in ozonated waters (3,6,9,(10)(11)(12).…”

Parameters for Evaluation of the Fate, Transport, and Environmental Impacts of Chemical Agents in Marine Environments

“…64 Additionally, cyanogen chloride is formed from the chlorination of drinking water containing aromatic compounds and ammonium ion. 65,66 The United States produced roughly 12 500 tons of cyanogen chloride during World War II, 38 and the compound has been loaded into several American chemical munitions. 39 An estimated 205 tons of cyanogen chloride was disposed in U.S. coastal waters.…”

Control of disinfection by-products and biodegradable organic matter through biological treatment

“…Investigations of the impact of ozone as a pretreatment, foilowed by chlorination, hâve often shown a réduction in THM formation (RECKHOW and SINGER, 1984 ;JACANGELO et al 1989). The extent of réduction was found to dépend on the type of the wajer treated, the organic and inorganic compounds in water, the disinfectant dose, the contact time and the transferred ozone dose (TRUSSELL and UMPHRES, 1978).…”