Volatile Organic Acids In Compost: Production and Odorant Aspects

Samples of active and cured compost from across the U.S. are examined for volatile organic acids (VOA) in relation to other microbiological and chemical properties. VOA are considered important because they reflect temporal microbiological properties of active and cured compost that influence the potential for compost to become odorous and phytotoxic. Data collected from 712 compost samples reveals a wide range of concentration for VOA between 75 and 51,474 ppm (dry basis) with a mean concentration of 4,385 ppm. To understand the variability of VOA, technology and site-specific testing data are needed. The results underscore concern for phytotoxicity and odor release potential, as 15 percent of samples exceeded 10,000 ppm and 2.5 percent exceeded 25,000 ppm VOA. Data and methodologies presented are viewed as. useful to better understand relationships between compost biological activities and production of malodorous and phytotoxic VOA.