Analysis of Volatile Organic Compounds from Compost.

Area of Science:

• Environmental Science
• Analytical Chemistry
• Public Health

Background:

• US states divert food waste to compost, potentially reducing landfill greenhouse gas emissions.
• Compost volatile organic compound (VOC) emissions may include hazardous air pollutants and odors, raising public health concerns.
• Accurate methods for analyzing speciated VOCs in compost are crucial for understanding their sources.

Purpose of the Study:

• To develop and implement an effective two-component sampling method for analyzing VOCs in compost.
• To quantify VOC generation in different compost types (yard waste vs. mixed food/yard waste).

Main Methods:

• A novel two-component sampling system was used, combining a chilled impinger for water-soluble VOCs and dual sorbent tubes for hydrophobic VOCs.
• Headspace gas-chromatography with flame ionization detection (HS-GC-FID) and thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) were employed for VOC measurement.

Main Results:

• Higher VOC generation was observed in warmer compost piles.
• Concentrations reached up to 27,000 ppm for ethanol and 3,500 ppm for methanol.
• Alpha-Pinene and D-Limonene were detected above 1600 ppb.
• Methanol and ethanol were significantly more concentrated (over 1000x) in mixed food/yard waste compared to yard waste alone.
• Terpenes were slightly higher in yard waste compost.

Conclusions:

• The developed method effectively analyzes compost VOCs.
• Methanol levels in compost can exceed permissible indoor air quality standards, indicating potential health risks.
• Understanding VOC profiles in compost is essential for managing environmental and public health impacts.