Ozonation of algae and odor causing substances in eutrophic waters

Area of Science:

• Environmental Chemistry
• Water Treatment Technologies

Background:

• Earthy and musty odors in drinking water are a significant consumer concern, particularly in regions like Southern Taiwan during summer.
• Compounds such as geosmin (GSM), 2-methylisoborneol (2-MIB), and 2-furfural (2-FF) are primary contributors to these undesirable tastes and odors.

Purpose of the Study:

• To investigate the effectiveness of ozonation in removing GSM, 2-MIB, and 2-FF from eutrophic surface waters.
• To understand the influence of natural organic matter (NOM) on the ozonation process and the degradation of odorants.

Main Methods:

• Ozonation experiments were conducted on eutrophic surface waters containing GSM, 2-MIB, and 2-FF.
• Analysis of water parameters including dissolved organic carbon (DOC), humic substances, and specific ultraviolet absorbance (SUVA).
• Evaluation of the impact of NOM composition (aromatics, phenolics) on ozone demand and odorant destruction rates.

Main Results:

• High levels of DOC, humic substances, and SUVA indicated a significant ozone demand.
• The presence of NOM, particularly aromatics and phenolics, positively correlated with increased destruction rates of GSM, 2-MIB, and 2-FF.
• Ozone and hydroxyl radicals (OH.) effectively destroyed algae cells, leading to the release of extracellular organic matter (EOM).

Conclusions:

• Ozonation is a viable method for removing key odor-causing compounds from drinking water.
• The composition of natural organic matter significantly affects the efficiency of ozonation, influencing ozone demand and odorant removal.
• Understanding NOM characteristics is crucial for optimizing ozonation treatment for effective odor control in drinking water.