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Disinfection Byproduct Formation in Reverse-Osmosis Concentrated and Lyophilized Natural Organic Matter from a Drinking Water Source
Citation:
PRESSMAN, J. G., D. L. McCurry, S. Parvez, G. E. RICE, L. K. TEUSCHLER, R. J. MILTNER, AND T. F. SPETH. Disinfection Byproduct Formation in Reverse-Osmosis Concentrated and Lyophilized Natural Organic Matter from a Drinking Water Source. WATER RESEARCH. Elsevier Science Ltd, New York, NY, 46(16):5343-5354, (2012).
Impact/Purpose:
To inform the public.
Description:
Drinking water treatment and disinfection byproduct (DBP) research can be complicated by natural organic matter (NOM) temporal variability. NOM preservation by lyophilization (freeze-drying) has been long practiced to address this issue; however, its applicability for drinking water research has been limited because the selected NOM sources are a typical of most drinking water sources. The purpose of this research was to demonstrate that reconstituted NOM from a lyophilized reverse osmosis (RO) concentrate of atypical drinking water source closely represents DBP formation in the original NOM. A preliminary experiment assessed DBP formation kinetics in concentrated NOM, which demonstrated that chlorine decays faster in concentrate. Potential changes in NOM reactivity caused by lyophilization were evaluated by chlorination of lyophilized and reconstituted NOM, its parent RO concentrate, and the source water. Although total measured DBP formation tended to decrease slightly and unidentified halogenated organic formation tended to increase slightly as a result of RO concentration, the changes associated with lyophilization were extremely minor. In lyophilized NOM reconstituted back to source water TOC levels and chlorinated, the concentrations of 19 of 21 measured DBPs, constituting 96% of the total identified DBP mass, were statistically indistinguishable from those in the chlorinated source water. This study suggests that lyophilization can be used to preserve concentrated NOM without substantially altering the precursors to DBP formation.
