Odorous volatile organic compound (VOC) emissions from ageing anaerobically stabilised biosolids

Area of Science:

• Environmental Science
• Wastewater Treatment
• Analytical Chemistry

Background:

• Beneficial reuse of biosolids is crucial for nutrient recycling but often limited by odor emissions.
• Volatile organic compounds (VOCs) are key contributors to the nuisance odors associated with biosolids.
• Understanding the specific VOCs and their sources is essential for mitigating odor issues.

Purpose of the Study:

• To identify and quantify volatile organic compounds (VOCs) emitted from anaerobically stabilized biosolids.
• To determine which VOCs contribute most significantly to the characteristic odor of nuisance emissions.
• To investigate the changes in VOC emissions over a storage period.

Main Methods:

• Flux hood sampling was employed to collect VOCs emitted from biosolids stored under ambient conditions.
• Chemical analysis was performed to identify and quantify the detected VOCs.
• Odour activity values (OAVs) were calculated to compare the relative odor contribution of different compounds.

Main Results:

• Emitted VOCs varied over the 50-day storage period.
• Trimethylamine was identified as the most significant odorant based on OAVs, exceeding sulfur compounds.
• Other compounds like limonene, ethyl methyl benzene, and acetic acid were detected above their olfactory detection limits but had lower OAVs.

Conclusions:

• The identified VOCs originate from catchment sources, wastewater treatment processes, and biosolid storage.
• Trimethylamine is a key target compound for odor management strategies in biosolids.
• Effective odor control measures are necessary to enable the beneficial reuse of biosolids.