Intracellular Organic Matter from Cyanobacteria as
a Precursor for Carbonaceous and Nitrogenous Disinfection Byproducts
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Abstract
The
formation of total organic halogen (TOX), carbonaceous disinfection
byproducts (DBPs) (trihalomethanes (THMs) and haloacetic acids (HAAs)),
and nitrogenous DBPs (trichloronitromethane (TCNM) or chloropicrin,
haloacetonitriles (HANs), and nitrosamines) was examined during the
chlorination or chloramination of intracellular organic matter (IOM)
extracted from <i>Microcystis aeruginosa</i>, <i>Oscillatoria </i>sp. (OSC), and <i>Lyngbya </i>sp. (LYN). The percentage
of unknown TOX (22–38%) during chlorination indicated that
the majority of DBPs were identified among THMs, HAAs, TCNM, and HANs.
Bromide was readily incorporated into DBPs with speciation shifting
slightly from dihalogenated species to trihalogenated species. During
formation potential testing with chloramines, nitrosamine yields from
IOM were measured for <i>N</i>-nitrosodimethylamine (NDMA,
10–52 ng/mg<sub>C</sub>), <i>N</i>-nitrosopyrrolidine
(NPYR, 14 ng/mg<sub>C</sub>), <i>N</i>-nitrosopiperidine
(NPIP, 3.7–5.5 ng/mg<sub>C</sub>), and <i>N</i>-nitrosomethylethylamine
(NMEA, 2.1–2.6 ng/mg<sub>C</sub>). When IOM was added to a
natural water matrix, the nitrosamine yields were not realized likely
due to competition from natural organic matter. Ozonation increased
NDMA and NMEA formation and reduced NPYR and NPIP formation during
subsequent chloramination. In addition, ozone oxidation of IOM formed
detectable concentrations of aldehydes, which may contribute to DBP
formation. Finally, bioluminescence-based test results showed that
>99% of the IOM extracted from OSC and LYN was biodegradable. Therefore,
a biological treatment process could minimize this source of DBP precursor
material during drinking water treatment