TECHNICAL REPORTS Atmospheric Pollutants and Trace Gases Odor and Gas Release from Anaerobic Treatment Lagoons for Swine Manure

releases are also needed to evaluate odor effects through science-based setback models (Lim et al., 2000). Odor Odor and gas release from anaerobic lagoons for treating swine is evaluated by determining odor concentration (OC), waste affect air quality in neighboring communities but rates of release are not well documented. A buoyant convective flux chamber (BCFC) intensity, and hedonic tone (HT) (Lim et al., 2001). An was used to determine the effect of lagoon loading rate on measured odor unit (OU) is defined as the amount of odorant(s) odor and gas releases from two primary lagoons at a simulated wind in 1.0 m3 of odorous gas at the panel odor detection speed of 1.0 m s 1. Concentrations of ammonia (NH3), hydrogen concentration (European Committee for Standardizasulfide (H2S), carbon dioxide (CO2), sulfur dioxide (SO2), and nitric tion, 2002) and OC is defined in terms of OU m 3. An oxide (NO) in 50-L air samples were measured. A panel of human odor emission rate (OU s 1) results when OC is mulsubjects, whose sensitivity was verified with a certified reference odortiplied by volumetric airflow rate in m3 s 1 (Heber et ant, evaluated odor concentration, intensity, and hedonic tone. Geoal., 2002). metric mean odor concentrations of BCFC inlet and outlet samples Anaerobic treatment systems (lagoons) are used and of downwind berm samples were 168 44 (mean 95% confiwidely for practical treatment and storage of swine madence interval), 262 60, and 114 38 OUE m 3 (OUE, European odor unit, equivalent to 123 g n-butanol), respectively. The overall nure (National Engineering Handbook, 1999; Westergeometric mean odor release was 2.3 1.5 OUE s 1 m 2 (1.5 0.9 man et al., 1990). Lagoons are typically earthen basins, OU s 1 m 2). The live mass specific geometric mean odor release was and rely on bacteria to stabilize organic material (Pork 13.5 OUE s 1 AU 1 (animal unit 500 kg live body mass). Overall Industry Handbook, 1998). Lagoons are relatively simmean NH3, H2S, CO2 and SO2 releases were 101 24, 5.7 2.0, 852 ple to operate and maintain, and are relatively inexpen307, and 0.5 0.4 g s 1 m 2, respectively. Nitric oxide was not sive compared with other treatment methods (American detected. Odor concentrations were directly proportional to H2S and Society of Agricultural Engineers, 1997). Lagoons beCO2 concentrations and odor intensity, and inversely proportional to come more odorous when overloaded due to sludge hedonic tone and SO2 concentration (P 0.05). Releases of NH3, buildups, infrequent additions of large amounts of maH2S, and CO2 were directly proportional (P 0.05) to volatile solids nure, and cold weather (Ritter, 1989). loading rate (VSLR). The traditional wisdom of agricultural engineers has been that a properly designed and operated anaerobic lagoon will have minimal odor problems, except in L operations in the USA have become larger spring when lagoon temperature rises and bacterial acand more concentrated due to economic factors. tion increases (Hamilton and Cumba, 2000). However, Public concerns regarding air, water, and soil pollution all lagoons generate some odor; the quantity has not have accompanied the increase in size of production been well documented (Heber et al., 2002). Lagoon odor facilities. To address these public concerns, baseline aecan be reduced by maintaining adequate dilution and rial pollutant emissions from typical manure storage and improving loading uniformity by introducing smaller treatment facilities are needed to assess the magnitude amounts of manure more frequently. Anaerobic lagoons of air pollution and effectiveness of pollution abatement are designed on the basis of volatile solids loading rate technologies such as aeration, solids separation, and (VSLR) (National Engineering Handbook, 1999). The covers (Ritter, 1989; Zhang et al., 1996). acceptable VSLR varies from one location to another Measurements of the character and quantity of odor since the rate of solids decomposition in anaerobic lagoons is a function of temperature. T.-T. Lim, A.J. Heber, J.-Q. Ni, and P. Shao, Agricultural and Biological Engineering Dep., and A.L. Sutton, Animal Sciences Dep., Purdue Abbreviations: AU, animal unit; BCFC, buoyant convective flux Univ., West Lafayette, IN 47907. Contribution no. 16556 from the chamber; BIW, equivalent concentration of n-butanol in water; DT, Purdue University Agricultural Research Program. Mention of spedilutions to threshold; HT, hedonic tone; OC, odor concentration; cific equipment is for the benefit of readers and does not infer endorseOCE, odor concentration normalized to European odor units; ODCb, ment or preferential treatment of the product names by the authors. odor detection concentration of n-butanol gas; OU, odor unit; OUE, Received 20 Nov. 2001. *Corresponding author ([email protected]). European odor unit, equivalent to 123 g of n-butanol; VSLR, volatile solids loading rate. Published in J. Environ. Qual. 32:406–416 (2003).