Formation of HAAs during Chlorination of Aspartic Acid in Drinking Water

Abstract

As a traditional disinfection method, chlorination disinfection is used generally in the plants ,however, disinfection by-products (DBPs) during chlorination process generate accordingly. Nitrogenous organic compounds is a kind of important precursors of DBPs. Haloacetic acids (HAAs) is one kind of the main DBPs. Aspartic acid (Asp) is one kind of elementary amino acids,which are typical nitrogenous organic compounds.In this paper, the formation characteristics of HAAs by Asp under different chlorination disinfection conditions have been researched, such as reaction time, chlorine dosage, pH, temperature and Br- . The results show that the yields of dichloroacetic acid(DCAA) and trichloroacetic acid(TCAA) are both increased with the reaction time increasing,and the formation rates is accelerated at the initial period; With the increase of chlorine dosage, the yields of DCAA and TCAA increased; The yield of DCAA and TCAA are both low in the acidic condition and high in the conditions of neutral and alkaline conditions. The yield of DCAA and TCAA increased with the increase of temperature. When there is Br- in water, bromided-HAAs can be formed.The total HAAs yield and BIF both increase with the increase of Br- concentration. The HAAs constituents contain DCAA,TCAA,BCAA,DBCAA, DCBAA, DBAA and TBAA. At low Br- concentration,the order of HAAs constituents yields is DCAA>BCAA>DCBAA>TCAA>DBCAA> DBAA>TBAA.