Entwicklung von Methoden zur weitergehenden Erfassung und Vermeidung von Nebenprodukten bei der Desinfektion von Trinkwasser Abschlussbericht

A simple procedure is introduced which allows the extremely sensitive quantification of disinfection by-products (DBP), such as trihalomethanes, halogenated acetic acids, dihalogenated nitriles, ketones, trichloronitromethane, and chloral hydrate in a concentration range of 0.02 up to 10 #mu#g/l. Several waters were tested in a pilot scale treatment plant in their ability of forming DBPs after disinfection as well as oxidation. In a further study with the dependence of DBP formation to the water quality and treatment conditions, natural as well as artificial waters were treated under different conditions, leading to the following results: The concentration of the halogenated DBPs formed is increasing by reaction time and the amount of chlorine. - An elevation of the pH above 9 leads to lower DBP concentrations, which is useless regarding the disinfection potential of chlorine which is decreasing with an increasing pH-value. - Decreasing the pH under 7 also leads to a decreasing amount of DBPs, while there is a shift to halogenated acids and brominated compounds. In case to study the effects of different natural water compounds on DBP formation, different humic acids, proteins, sugars, amino sugars, and amino acids were added to pure and natural water. After chlorination of these water samples the following results were obtained: - There is no effect of sugars and amino sugars on the formation of adsorbale organic halogens (AOX) and DBP. - Proteins are leading to the formation of a high AOX, while the amount of the identified DBPs is quite low. The chemical trace analysis of DBPs formed during the chlorination of drinking water seems more effective in combination with the detection and identification of unknown gentoxic substances. In order to-examine slightly contaminated water by short term gentoxicity tests as well as organic trace analysis an extraction and enrichment of the water ingredients is necessary. Utilizing the method of volume reduction by partial reflux the enrichment of highly volatile compounds is possible. These concentrates can be examined by a gentoxicity test as well as by GC/MS. The method was successfully applied to chlorinated waters from different origins. Gentoxic effects were detected even in waters chlorinated with a chlorine dose of 0,3 mg/l. (orig.)Available from TIB Hannover: F96B1756+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman