A framework for identifying characteristic odor compounds in municipal wastewater effluent

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Water Quality

Background:

• Municipal wastewater effluent can contaminate drinking water sources, affecting water aesthetics and public trust.
• Trace organic compounds in wastewater pose a challenge for maintaining potable water quality.
• Aesthetic issues in drinking water can arise from even small amounts of wastewater intrusion.

Purpose of the Study:

• To develop and apply an analytical framework for identifying and monitoring odor-causing compounds in wastewater effluent.
• To pinpoint specific chemicals responsible for undesirable odors in drinking water derived from wastewater sources.
• To assess the contribution of various organic compounds to the overall odor profile of wastewater.

Main Methods:

• Utilized a combination of gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-Olf).
• Employed Flavor Profile Analysis (FPA) to characterize and prioritize odor impacts.
• Identified odorants based on retention indices, mass spectra, odor descriptors, and confirmation with authentic standards.

Main Results:

• Earthy-musty odors were dominant in wastewater effluent, primarily from 2,4,6-trichloroanisole (246TCA), geosmin, and 2-methylisoborneol (2MIB).
• Additional odors from amine, sulfidic, and fragrant categories were detected.
• Other identified odorants included 2-pyrrolidone, methylnaphthalenes, vanillin, and 5-hydroxyvanillin (5-OH-vanillin).

Conclusions:

• The integrated analytical approach effectively identified key odorants in wastewater effluent.
• Specific compounds like geosmin and 2MIB are significant contributors to earthy-musty odors in wastewater.
• Further research on the fate of identified odorants is recommended for water systems receiving wastewater effluent.