Polar nitrogen compounds and their behaviour in the drinking water treatment process

Aliphatic and alicyclic amines as well as ethanolamines are extremely polar compounds, frequently found in the environment, and some of them have high toxicity. To address the contamination of selected German surface waters e xamined and the importance of bank filtration in Eastern Germany, investiga tions on the behaviour of polar organic nitrogen compounds during water tre atment were carried out. Test conditions were designed appropriately for dr inking water treatment conditions, and the tests were carried out using mod el water as well as bank filtrate. Test filter studies of microbial degrada tion of selected compounds demonstrated the following order of biodegradabi lity: ethanolamine>dimethylamine>pyrrolidine> ethylenediamine/piperidine>di ethylamine>morpholine>piperazine>cyclohexylamine. Flocculation tests using iron salts as well as aluminium salts as coagulants showed very low removal rates for the amines. The best results for the removal of the polar organi c nitrogen compounds from the water were obtained using ozonation. Based on the reaction-rate constants, the order of degradation by ozone is: piperaz ine>morpholine>ethylenediamine>piperidine, cyclohexylamine>dimethylamine >e thanolamine>pyrrolidine>diethylamine. Disinfection by chlorine-containing a gents under drinking water treatment conditions did not give effective elim ination of the selected polar nitrogen compounds. (C) 2001 Elsevier Science Ltd. All rights reserved.