Equilibrium Sampling Used to Monitor Malodors in a Swine Waste Lagoon

Authors: Loughrin, John; Lovanh, Nanh; MAHMOOD, REZAUL - WESTERN KY UNIVERSITY

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/22/2007
Publication Date: 1/14/2008
Citation: Loughrin, J.H., Lovanh, N.C., Mahmood, R. 2008. Equilibrium Sampling Used to Monitor Malodors in a Swine Waste Lagoon. Journal of Environmental Quality. 37:1-6

Interpretive Summary: When conducting emission of malodors from animal rearing facilities, it is desirable to also obtain measurement of the responsible compounds from their source. We monitored malodorous compounds in a lagoon that received waste from approximately 2,000 sows. Malodorous compounds were measured by the use of samplers consisting of submersible stir plates and stir bars to adsorb the compounds from the water. Malodors were monitored from the late summer to middle fall of 2006, during which time air and water temperatures were also tracked. Initially, the samplers were deployed at various depths until the lagoon was drained for crop application in mid-September. Afterwards, all samples were taken near the water surface at three locations within the lagoon. During the same period, we also measured suspended solids and chemical oxygen demand (COD), a measure of the amount of organic compounds dissolved in the water. Samplers were deployed for three hours. Levels of malodorous compounds were higher at the surface of the lagoon than at the middle or bottom of the lagoon. During the span of lagoon drainage, concentrations of malodorous compounds fluctuated widely, increased 16-fold as compared to the period immediately before drainage, and continued to increase as fall progressed and temperatures cooled. COD was the only other water quality parameter that showed an increase comparable to that of the malodorous compounds after lagoon drainage.

Technical Abstract: When conducting measurements of malodors from CAFOs, it is desirable to determine the levels of responsible compounds at the source of emission. We monitored malodorous compounds in a 0.4 ha anaerobic lagoon that received waste from approximately 2,000 sows. Compounds were measured by the use of equilibrium samplers consisting of submersible stir plates and stir bar sorbtive sampling using polydimethylsiloxane-coated magnetic stir bars. Malodors were monitored from the late summer to middle fall of 2006, during which time air and water temperatures were also tracked. Initially, the samplers were deployed at depths of 10 to 170 cm at two sites within the lagoon until it was drained for crop application in mid-September. Afterwards, all samples were taken at a depth of 10 cm at three locations within the lagoon. During the same period, we measured suspended solids, chemical oxygen demand (COD), and pH in the lagoon. Samplers were deployed for three hours. Levels of malodorous compounds were higher at the surface of the lagoon than at the middle or bottom of the lagoon. Skatole concentration, for instance, averaged 54, 24, and 38 ng mL-1 near the surface, in the middle, and at the lowest sampling depths, respectively. During the span of lagoon drainage, concentrations of malodorous compounds fluctuated widely, increased 16-fold as compared to the sampling period prior to drainage, and continued to increase as fall progressed and temperatures cooled. COD was the only other water quality parameter that changed as dramatically as did the levels of malodorous compounds during this period.