Volume 2 • Issue 4 • 1000117 J Civil Environ Eng ISSN: 2165-784X JCEE, an open access journal Civil & Environmental Engineering Rahman and Borhan, J Civil Environ Eng 2012, 2:4 http://dx.doi.org/10.4172/2165-784X.1000117 Review Article Open Access Typical Odor Mitigation Technologies for Swine Production Facilities - A Review S. Rahman 1 * and M. S. Borhan 2 1 Assistant Professor, Agricultural and Biosystems Engineering, North Dakota State University, Fargo, North Dakota 2 Research Specialist, Agricultural and Biosystems Engineering, North Dakota State University, Fargo, North Dakota Abstract Odorous air emissions from confined animal feeding operation are causing public nuisance. Accordingly, different odor mitigation technologies were designed, developed, and evaluated in the last decades to reduce odor emissions. The purpose of this paper is to review the previous research related to odor mitigation from swine rearing facilities and provide information on the effectiveness of currently available and emerging odor mitigation technologies. This review focused on odor mitigation approaches at different stages of swine production, manure storage and handling, and land application. Several odor mitigation technologies have been suggested and evaluated including diet manipulation, solid-liquid separation, additives, aeration, anaerobic digestion, lagoon covers, biofilters, acid scrubbing, shelterbelts, and manure injection. The effectiveness of these mitigation technologies varied widely; however, diet manipulation, biofilters, shelterbelts, and direct injection of manure have shown advantages over other odor mitigation methods. Diet manipulation is the first line of defense for odor mitigation. Biofilters and shelterbelts provide solutions for treating the odorous air before releasing to atmosphere, whereas additives, lagoon covers, aeration, and anaerobic digestion reduce or control odor emissions during manure storage and treatment. Direct injection of manure provides ultimate disposal solution and can reduce odor significantly compared to surface application. *Corresponding author: Shafiqur Rahman, Agricultural and Biosystems Engineering, North Dakota State University, 7620, PO Box 6050, Fargo, ND, 58108, USA, Tel: 701-231-8351; Fax: 701-231-1008; E-mail: s.rahman@ndsu.edu Received May 15, 2012; Accepted June 13, 2012; Published June 15, 2012 Citation: Rahman S, Borhan MS (2012) Typical Odor Mitigation Technologies for Swine Production Facilities - A Review. J Civil Environ Eng 2:117. doi:10.4172/2165- 784X.1000117 Copyright: © 2012 Rahman S, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Keywords: Odor; Mitigation technologies; Swine feeding operation Introduction Due to intensive livestock farming, a large amount of animal excreta (i.e., faeces, urine, undigested feed, etc.) is produced in a smaller area that can lead to air pollution problem including excessive odors and gaseous emissions. As livestock and poultry operations expand, concentrated odor complaints from the neighbouring communities increase. Pork production, an important sector of the United States animal agriculture [1], is not immune to such complaints. Odors are a nuisance in the nearby community because of the persistent repulsive smell and potential health risks [2]. Odors from swine operations have been associated with lower quality of life [3,4] and loss of property values in the surrounding communities. Oſten, odor management is a limiting factor for modifying and expanding an existing swine facility or establishing a new one, as well as for the sustainability, productivity, and profitability of this industry [5]. It has been postulated that the future of the swine industry will largely and collectively depend on technologies that are able to mitigate odor effectively [6,7]. e purpose of this paper is to present different aspects of odor from livestock production facilities, especially from swine operations, and available technologies to mitigate odor nuisance. Constituents of livestock odor An odor is a product of a complex interaction and mixing of individual odorous and non-odorous components that are produced during anaerobic degradation of organic matter in animal manure [8,9]. Generally, livestock manure consists of undigested organic residues including proteins, carbohydrates, and fats [10]. ese compounds degrade anaerobically and produce nuisance odorous compounds [10,11]. More than 168 volatile compounds have been identified in swine farms, many of which not only are responsible for unpleasant odors [11-13], but also affect the comfort, health, and production efficiency of animals as well as the comfort and health of workers [11]. Similarly, other researchers indicated that over 160 odorous compounds have been identified in manure, many of which are produced by the breakdown of manure protein [14]. Livestock producers face increasing pressure from regulators and neighbouring communities to control odor and livestock producers must comply with increasingly stringent regulations on pollutant gas emissions as required by local, state, and federal regulatory agencies. No single compound has been linked as a surrogate to odor and there is little linkage between major odor compound classes identified by researchers [15]. Presently, odors are believed to be transported either directly through vapor phase or through attachment onto particulate matter. Accordingly, solutions to odor control from Animal Feeding Operations (AFO) may include control of both odorous compounds and particles that transport the compounds. ose complexity of compound and transport mechanism associated with odor have made the quantification and mitigation of odor challenging. Several odor mitigation technologies are available based on odor production source and animal types. Full descriptions of these technologies are beyond the scope of this review. erefore, this review will concentrate on current and emerging odor mitigation technology options and their effectiveness at different stages of swine production operations and manure management systems. Sources of odor An animal production facility is a major source of odor. Feed and body odors are not regarded as offensive, but odor generated from anaerobic decomposition of manure and during collection, handling, storage, and land application are considered offensive [11]. Odor emitted from manure is primarily due to an incomplete degradation of the organic matter contained in the manure such as protein, carbohydrates, and fats. Odorous compounds can be divided into five different chemical classes [16]: i) Volatile Fatty Acids (VFAs), ii) aromatic compounds (i.e., indoles and phenols), iii) nitrogen-