The Bactericidal Efficiency of the Ammonia‐Chlorine Treatment

Abstract

The marked success which the ammonia-chlorine treatment has met during the past two years throughout the United States in the prevention of tastes and odors commonly associated with the chlorination of water supplies, coupled with the simplicity and the low operating and first costs of the process, has made it expedient for Chicago to give the treatment careful consideration.It was apparent from the beginning that, in giving consideration to the use of the ammonia-chlorine treatment, it would be necessary to determine carefully what the bactericidal velocity of the treatment was as compared with that obtained in ordinary chlorination practice. A slowing up of the bactericidal action would be of great disadvantage if the treatment were to be applied at the Chicago pumping stations, because of the lack of protection it would afford to nearby consumers, many of whom receive their water in less than three minutes after it is chlorinated. If such delayed action actually occurred, and it was considered advisable to use the treatment, it would be necessary to provide sufficient detention period to obtain the required bactericidal effect before the water was pumped into the system.The literature on this subject was not conclusive; some observers noticed a decided lag in bactericidal velocity, while others observed none. The investigations made by Holwerda" and more recently by Baker and Schmelkes" indicate that the widely varying effects observed were probably due to the application of the treatment to waters of different hydrogen-ion concentrations.

Persistence of Combined Available Chlorine Residual in Gary‐Hobart Distribution System

“…losses were not as sharply delineated, this trend was also observed in laboratory work on the bactericidal efficiency of combined available chlorine treatment in Chicago (5) .…”

Chemical Methods in Slime and Algae Control

“…In most cases, chloramines are slower acting than chlorine, requiring thirty minutes to two hours for complete killing (19). The toxic action is spread over a longer period of time, and in the end chloramine is usually more efficient.…”