An investigation of odors and volatile organic compounds released during composting

The emissions of odors and volatile organic compounds produced from a comme rcial composting operation have been studied using a laboratory-scale compo sting system. The composting activity of a typical commercial compost feed was followed by monitoring the composting temperature, as well as the respi ratory rate. Using a controlled aeration system, the gaseous volatiles prod uced were tested for odors using the "dilution-to-threshold" method, as wel l as gas composition, as determined by gas chromatography-mass spectrometry . The results indicated that while there may be a reasonable correlation betw een the release of volatile organic compounds (VOCs) and odors, care has to be taken when trying to identify offensive odors with specific chemical sp ecies. However, the data obtained suggests that offensive odors formed duri ng commercial composting may be due to sulfurous and nitrogenous compounds, although their concentrations in the compost gases may not he very high. The major release of VOCs occurred during the first two weeks of composting , after which the gaseous releases fell dramatically as the composting proc ess proceeded and temperatures started to fall.