Ozonation of Algae and Odor Causing Substances in Eutrophic Waters

Abstract

Consumers generally concern taste and odor in drinking water. In the Southern Taiwan, more than 5,000,000 people are suffered from earth/musty odor in drinking water, especially in the summer. Thus, ozonation of geosmin (GSM), 2-methylisoborneol (2-MIB), and 2-furfural (2-FF) in eutrophic surface waters has been studied in the present work. Experimentally, it was found that the water contained high dissolved organic carbon (DOC), humic substances, and specific ultraviolet absorbance (SUVA) resulting the highly ozone (O₃) demand. The natural organic matters (NOM) in the waters had a significant effect on the ozonation of GSM, 2-MIB and 2-FF. Their destruction rates were increased with high contents of aromatics, phenolics, and SUVAs. In addition, during ozonation of raw waters, O₃ and OH· played an important role in destruction of algae cells and caused excretion of extracellular organic matter (EOM) to the bulk phase.

Key Words: :

• Odor
• Algae
• Ozonation
• Geosmin
• 2-Methylisoborneol
• 2-Furfural
• Extracellular organic matter.

ACKNOWLEDGMENT

The authors acknowledge the financial support by National Science Council, Taiwan, R.O.C. under contract No. NSC 93-2211-E-241-006.

Notes

^aSpecific UV absorbance (cm⁻¹/mg/L).

^b(hydrophobic fraction: hydrophilic fraction).

^aExisting in raw water.

^bIdentified by comparison with standards.

^cIdentified by library databases.

^dND: Not detected.

^e+100: Generated compound.

^aTotal organic carbon.

^bSpecific UV absorbance (m⁻¹/mg/L).

^cSamples number, n = 3.

^aMilli-Q pure water.