Study of the possible origins of chlorinous taste and odour episodes in a distribution network

Occasionally in winter some inhabitants of the city of Paris complain of a bad chlorinous odour when the chlorine residual in the water distribution n etwork is 0.1 mg/l. Several hypotheses have been made. Many taste and odour profiles have been made on one plant and aminoacids and aldehydes have bee n analysed. Chlorination of urea has not led to the chlorinous taste. We th ink that these odours are due to trichloramine, which is produced by chlori nation of some organo nitrogen compounds with a slow kinetics of formation during winter, Results show that the combined chlorine level is constant wi th time and we have reproduced this offensive odour but the origin does not seem to be aldehydes. (C) 1999 IAWQ Published by Elsevier Science Ltd. All rights reserved.