N-Nitrosodimethylamine Formation from Hydrazine Compounds on Ozonation

N-Nitrosodimethylamine formation from six hydrazine compounds on ozonation was investigated. N-Nitrosodimethylamine formation yields in groundwater (pH 7) were 7.5%-89%. Results in the presence of tert-butyl alcohol indicated that N-nitrosodimethylamine was formed by reaction with molecular ozone, except for tetramethyltetrazene. From the results of effects of pH, tert-butyl alcohol and water matrix (groundwater and river water), it was suggested that reactions of tetramethyltetrazene with ozone, hydroxyl radicals, etc., were associated with N-nitrosodimethylamine formation. Some reactions restricted N-nitrosodimethylamine formation. Because N-nitrosodimethylamine formation of hydraxine compounds on chloramination was low, they are more important N-nitrosodimethylamine precursors on ozonation in actual water treatment.