In drinking water treatment, adsorption rate of 2-methylisoborneol (2-MIB) to powdered activated carbon can be reduced by natural organic matters (NOM). The objectives of this study are to investigate adsorption rate of 2-MIB on powdered activated carbon in raw water obtained from 21 water treatment plants in all over Japan under a non-equilibrium condition, and to clarify substances competing with the 2-MIB adsorption. Eighty-four percent of 2-MIB dissolved in ultrapure water was removed by a powdered activated carbon, whereas the removal rates were fallen within the range of 26~55% in the case of raw water solutions under the condition. Correlations between main fluorescence spectrum of each raw water sample extracted by three-dimensional excitation emission matrix and corresponding 2-MIB adsorption rate suggested that fluvic acid-like substances and low molecular weight substances (less than 1 kDa) greatly contributed to reduce the 2-MIB adsorption rate. They were also indicated that both of total organic carbon (TOC) and dissolved organic carbon (DOC) were useful index for predicting the injection amount of powdered activated carbon for 2-MIB treatment in raw water.

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