ARS | Publication request: Evaluation of odors associated with land application of biosolids

Submitted to: Journal of Residuals Science & Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 1, 2010
Publication Date: April 30, 2010
Citation: Barth, E.F., Forbes, R., Clark, P., Foote, E., Mcconnell, L.L. 2010. Evaluation of odors associated with land application of biosolids. Journal of Residuals Science & Technology. 7:73-80.

Interpretive Summary: Nuisance odors are one of the chief complaints associated with human and animal waste (fecal) management activities. Specific compound classes associated with these odors may include sulfur compounds (hydrogen sulfide, mercaptans (or thiols), and other organic sulfur compounds), nitrogen compounds (ammonia, amines) and volatile fatty acids. These odors may be a nuisance or elicit health complaints that are poorly understood. Scientists from the US Environmental Protection Agency, USDA-ARS, along with several other organizations, performed a field study of a biosolids land application process. The primary objective for this task was to determine the presence and concentrations of a selected group of organic and inorganic compounds and odorants in emissions from samples collected within and downwind of the application area of the biosolids land application test site. Flux chambers were used to collect emissions from the biosolids, and air samples were analyzed for a number of odorants over a 196 h period. The highest concentrations of compounds such as hydrogen sulfide and ammonia were found just after application, but none were above levels of concern for human health, and concentrations decreased significantly within 4 hours after application.

Technical Abstract: An odor study was performed at a biosolids application demonstration site using several different gas collection devices and analytical methods to determine changes in air concentration of several organic and inorganic compounds associated with biosolids application over various time periods. Various organic and inorganic odorants were detected at 1.5 m above the ground surface within the biosolids application zone area immediately after application. They then decreased to non-detectable levels within 196 h after application, consistent with other biosolids application studies. Air samples collected from flux chambers installed within the application zone contained detectable concentrations of various organic odorants immediately after biosolids application. The concentrations of these odorants may have been influenced by the increased temperature within the flux chambers, and the change in concentration of these odorants over time was affected by the various sample analysis method. Airborne concentrations of ammonia and hydrogen sulfide rapidly decreased within 4 h after biosolids application, and they further decreased to non-detectable levels within 196 h after application. The highest measurements for both ammonia and hydrogen sulfide did not approach any health criterion or guidance levels for these compounds. The effects of the specific biosolids process and management variables on odor generation were not studied.