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L'objectif principal de cet article est de montrer que les travaux de recherche enchimie de l'eau sont absolument nécessaires à la compréhension des phénomènes régissant laqualité des eaux de consommation produites et distribuées, ainsi qu'au développement detechnologies innovantes dans le domaine du traitement de ces eaux. Pour l'atteindre, il aété choisi de présenter trois exemples des recherches menées à l'Université de Poitiers et àl'École Polytechnique de Montréal : deux exemples de recherche fondamentale, sur lesmatières organiques naturelles et sur les mécanismes d'oxydation par les radicaux hydroxyleet un exemple de la recherche d'application, sur l'évolution de la qualité de l'eau lors deson traitement biologique par ozonation couplée à la filtration sur charbon actif engrains.The main purpose of this paper is to demonstrate that a better understanding ofchemical reactions and a better technologies development for the drinking water treatmentabsolutly needs research in water chemistry. In order to reach this objective, two examplesof recent fundamental research works in water chemistry and one example of research appliedto drinking water treatment have been selected.The first one concerns a fundamental research on characterization and analysis ofnatural organic matter. Nowadays, the main analytical tools used for quantification of NOMare DOC (BDOC for the biodegradable fraction) and UV-absorbance. However, a better knowledgeof NOM would be useful to predict water quality and determination of doses of some treatmentchemicals, such as coagulants and oxidants. This paper presents some data about (i) NOMfractionning by XAD macroporous resins and relationship between UV-absorbance and 13C-NMR,and (ii) study of chlorination of the isolated fractions. Based on these results, one cansuppose that aquatic NOM could be soon easily fractionnated and characterized by simplesanalytical tools. However, many research works are still necessary, particularly on thefield of relationships between data of "heavy" analytical tools (13C-NMR, pyrolysis/GC/MS,etc.) and more simple others (UVA/DOC, BDOC, fluorescence etc.).The second paragraph of the paper relates oxidation mechanisms by hydroxyl radicals.In ozonation of drinking water, currently applied in the drinking water treatment, OHradicals production is a necessary consequence, considered as the main action of ozone bysome authors. So, disinfection quality, bromate production, BDOC formation, pesticidesremoval will never be entirely understood as long as hydroxyl radicals participation inozonation processes will not be really cleared up. To illustrate this purpose, the exampleof ozonation of a free aminoacid (glycine) by molecular ozone and by OH radicals is shown.Oxidation by "pure" OH radicals, produced by radiolysis, as compared to oxidation bymolecular ozone, (at acidic pH in the presence of radical scavengers) shows that twomechanisms are really different. So, some works published some years ago, mixed up the twopathways. Such mechanisms on aminoacids oxidation should allow to understand some moredescriptive data on water disinfection and pesticides oxidation.The third example concerns the changes of water quality during ozone/GAC treatment. Itis well known that ozonation of naturel waters leads to an enhancement of waterbiodegradability, in terms of BDOC increase. So, if this BDOC is not removed in the plant,it can be the origin of bacteria regrowth in distribution system. The solutions are eitherto include, after ozonation step, a biological treatment step on activated carbon (BAC), orto increase chlorination doses applied in final disinfection. The effects of BAC treatmenton BDOC and ozonation by-products removals, in the case of the drinking water treatmentplant of Sainte-Rose (City of Laval, Quebec, Canada), are described. Finally, taking intoaccount the cost of such a process, the last paragraph of this paper gives somerecommandations for conception on BAC treatment.As for general conclusion, some new research topics in water chemistry for thedrinking water treatment are enumerated and some ideas about organization and development ofapplied and fundamental researches in water chermistry for the drinking water treatment, aregiven

Le Traitement des Eaux de Consommation : La Nécessité d'une Recherche en Chimie de l'Eau