Formation of trihalomethanes from dyes by ozone treatment

Abstract The amount of chloroform produced from dyes (orange II, methylene blue, and methylrosanilinium chloride) and humic acid by adding chlorine after the ozone treatments was investigated. Some dyes and humic acid were degraded by ozone and produced polar and acidic organic compounds. The amount of chloroform produced from orange II increased or decreased with the ozonization time, while that produced from methylene blue and humic acid decreased with ozonization time. Methylrosanilinium chloride did not produce the trihalomethane by chlorine disinfection. Thus, some but not all dyes produce trihalomethanes by ozone treatment and chlorine disinfection.