The generation of hazardous disinfection by-product is one of the major problems in drinking water chlorination. This study aims to investigate the potential of potassium ferrate (K2FeO4) on by-product control. Filtered raw water from a water treatment plant in Jinan was used to evaluate the effects of K2FeO4 dose, pH, ammonia nitrogen, and Br- concentration on trihalomethane formation potential (THMFP) and haloacetic acid formation potential (HAAFP). The results present that 3 mg/L K2FeO4 effectively reduced ultraviolet absorbance at 254 nm (UV254) by 45%, but removed little dissolved organic carbon (DOC) by 12% at pH 7.40, since K2FeO4 tends to attack the electron-rich part of organic matter molecules but with restricted mineralization ability. Fluorescence excitation-emission matrix (EEM) analyses indicate the effective removal of fulvic acid and humic acid. Increasing K2FeO4 dose reduced THMFP but increased HAAFP, due to their precursors reacting with K2FeO4 in different pathway, while the rising pH or Br- concentration increased THMFP but decreased HAAFP. Both THMFP and HAAFP decrease with increasing ammonia nitrogen concentrations. Additionally, it was found that under alkaline conditions, trihalomethanes (THMs) were dominated by haloacetic acids (HAAs).
Keywords: Disinfection by-products; Ferrate; Haloacetic acid formation potential; Trihalomethane formation potential.
© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.