The formation of haloacetamides, as an emerging class of N-DBPs, from chlor(am)ination of algal organic matter extracted from Microcystis aeruginosa, Scenedesmus quadricauda and Nitzschia palea

Abstract

Critical algal blooms in lakes increased the concentration of algal organic matter (AOM), significantly altering the drinking water treatment requirements, including coagulation, oxidation and disinfection. This study utilized Microcystis aeruginosa (cyanobacteria), Scenedesmus quadricauda (Chlorella) and Nitzschia palea (diatom) as models to investigate the AOM's primary characteristics and their contribution to the formation of chloroacetamides as novel disinfection byproducts (DBPs). Spectral analysis was used to characterize the proteins, carbohydrates and amino acids in AOM. The generation of chloroacetamides during chlor(am)ination was determined by gas chromatography with electron capture detection. Although Microcystis aeruginosa is the dominant species in freshwater worldwide, the AOM of Nitzschia palea showed the highest dissovled organic carbon (DOC) formation (4.02 or 1.42 ng per cell in extracellular organic matter (EOM) or intracellular organic matter (IOM), respectively). Scenedesmus quadricauda, as a typical green algae, showed the greatest formation potential of chloroacetamides in chlor(am)ination. Monochloroacetamide was the dominant chloroacetamide, which has not previously been reported and differed from the results reported for other precursors. In summary, AOM should be considered an important precursor for the formation of chloroacetamides.