Full Description

Non-ionic or anionic polymers are largely used as flocculants in drinking water treatment.While the use of synthetic cationic polymers in the U.S. and other countries is a common practice, inFrance these chemicals have just received approval from the health and sanitary department asmaterials to be used for drinking water. Cationic polymeric coagulants can be efficient for enhanced coagulationof surface waters or for direct filtration of source waters. Tests with these coagulants have beenperformed during the 2001-2003 period, at laboratory and pilot scale, to prepare the use on drinkingwater works at industrial scale during 2004.This study focused on the selection and the assessment of the technical and economic interest forusing cationic polymers as coagulants for drinking water. The objective was to establish the level ofclarification process performance that can be achieved on various types of waters for both natural organic matter (NOM) andturbidity removal and the corresponding type and dose of chemical. The major interest of the testedpolymers has been found to be their joint use with mineral coagulant: combination with aluminum saltfor enhanced conventional coagulation and with ferric salt for direct filtration. The optimal substitutionratio of mineral coagulant by organic coagulant has been found to be 30%. Potential byproductsformation (NDMA) have been controlled during the tests. Under the usual operating conditions (polymerdose and disinfectant residual) no NDMA was formed and therefore the risk of byproducts formationwas evaluated to be very low. Includes 28 references, tables, figures.

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Edition: Vol. - No. Published: 11/15/2004 Number of Pages: 14File Size: 1 file , 340 KB