Education

Publications

Acidifier application rate impacts on ammonia emissions from US roaster chicken houses

Shah, S. B., Grimes, J. L., Oviedo-Rondón, E. O., & Westerman, P. W. (2014), Atmospheric Environment, 92, 576–583. https://doi.org/10.1016/j.atmosenv.2013.01.044

Acidifier dosage effects on inside ammonia concentrations in roaster houses

Shah, S., Oviedo-Rondon, E. O., Grimes, J. L., Westerman, P. W., & Campeau, D. (2013), Applied Engineering in Agriculture, 29(4), 573–580. https://doi.org/10.13031/aea.29.9904

Ancillary effects of different acidifier application rates in roaster houses

Shah, S. B., Westerman, P. W., Grimes, J. L., Oviedo-Rondon, E. O., & Campeau, D. (2013), The Journal of Applied Poultry Research, 22(3), 565–573. https://doi.org/10.3382/japr.2012-00693

Live performance of roasters raised in houses receiving different acidifier application rates

Oviedo-Rondon, E. O., Shah, S. B., Grimes, J. L., Westerman, P. W., & Campeau, D. (2013), The Journal of Applied Poultry Research, 22(4), 922–928. https://doi.org/10.3382/japr.2012-00716

Nitrogen mass balance in commercial roaster houses receiving different acidifier application rates

Shah, S. B., Grimes, J. L., Oviedo-Rondon, E. O., Westerman, P. W., & Campeau, D. (2013), JOURNAL OF APPLIED POULTRY RESEARCH, 22(3), 539–550. https://doi.org/10.3382/japr.2012-00704

Ammonia emissions from broiler cake stockpiled in a naturally ventilated shed

Yao, H., Shah, S., Willits, D. H., Westerman, P. W., Li, L. W., & Marshall, T. K. (2011), Transactions of the ASABE, 54(5), 1893–1904. https://doi.org/10.13031/2013.39830

Phosphorus recovery from covered digester effluent with a continuous-flow struvite crystallizer

Westerman, P. W., Bowers, K. E., & Zering, K. (2010), Applied Engineering in Agriculture, 26(1), 153–161. https://doi.org/10.13031/2013.29471

Swine anaerobic lagoon nutrient concentration variation with season, lagoon level, and rainfall

Westerman, P. W., Ogejo, J. A., & Grabow, G. L. (2010), Applied Engineering in Agriculture, 26(1), 147–152. https://doi.org/10.13031/2013.29472

Impact of land application method on ammonia loss from hog lagoon effluent

Shah, S., Balla, B. K., Grabow, G. L., Westerman, P. W., & Bailey, D. E. (2009), Applied Engineering in Agriculture, 25(6), 963–973. https://doi.org/10.13031/2013.29236

Design and evaluation of a regenerating scrubber for reducing animal house emissions

Shah, S., Westerman, P. W., Munilla, R. D., Adcock, M. E., & Baughman, G. R. (2008), Transactions of the ASABE, 51(1), 243–250. https://doi.org/10.13031/2013.24217

View all publications via NC State Libraries

Grants

Waste Management in Hog Lagoons Using Bio-Magic

Blue and Green Solutions, Inc.(9/15/09 - 12/15/09)

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Waste Management in Hog Lagoons Using Bio-Magic

Sponsor: Blue and Green Solutions, Inc.

Start Date: 9/15/09

End Date: 12/15/09

Abstract

The goal of this proposal is to evaluate the efficacy of enzyme based products produced by Blue and Green Solutions Inc., for treating wastes from swine operations. Specifically this proposal aims to test G&B Bio-Magic M for its performance in reducing odors from swine lagoons. This research if successful has the potential to reduce odors and improve air quality in and around swine facilities. Additionally through this research, we expect to improve the health of animals and personnel working in the swine facilities.

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Effective strategies for biogas and nutrient management resulting from anaerobic digestion in covered swine lagoons

US Dept. of Agriculture (USDA)(9/01/08 - 6/30/12)

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Effective strategies for biogas and nutrient management resulting from anaerobic digestion in covered swine lagoons

Sponsor: US Dept. of Agriculture (USDA)

Start Date: 9/01/08

End Date: 6/30/12

Abstract

Biogas generation and capture using covered lagoons is a promising renewable energy technology that can be utilized by North Carolina swine farmers to increase on-farm income and mitigate rising energy costs. Covering lagoons would also reduce ammonia and greenhouse gas emissions, particularly methane, and have potential to obtain Carbon Credits. Currently, swine producers in the state have reservations about covering lagoons for biogas production as the economic recovery associated with energy generation equipment is unknown for NC and concerns about nutrient management have lead state officials to exclude covered lagoon projects from state conservation agricultural cost-share programs. An overlooked aspect of anaerobic digestion is the use of the nutrients in the production of crops that can be converted into value-added agricultural products. Algae and duckweed are examples of energy crops that could be grown in a media similar to digested swine wastes and then used in the production of biodiesel or bioethanol. The ultimate goals of this project is to exhibit effective, economically-feasible energy generation technologies utilizing biogas, demonstrate utilization of biogas combustion by-products (i.e. heat and CO2), and to show a variety of processes that can be implemented to manage swine effluent nutrients. The technologies to be demonstrated in this project include: 1.Anaerobic digestion of swine manure for biogas production and utilization of methane for electricity generation through an internal combustion engine, 2.Utilization of CO2 from methane combustion to enhance tomato production in greenhouse, 3.Nitrification biofiltration for ammonia emission control, very low cost denitrification in pits for nitrogen removal, and nutrient utilization for greenhouse tomato production, 4.Growing duckweed to recover nutrients from swine wastewater and convert duckweed into bioethanol, and 5.Struvite crystallization for phosphorus removal from swine wastewater. Also, technologies and extension education materials will be transferred to interested stakeholders. Workshops, field days, extension publications, and website spreadsheets and other materials will be developed from the knowledge obtained from this project.

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Phosphorus Recovery From Concentrated Wastewater With a Continuous-Flow Struvite Crystallizer

National Pork Board(5/01/07 - 5/01/09)

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Phosphorus Recovery From Concentrated Wastewater With a Continuous-Flow Struvite Crystallizer

Sponsor: National Pork Board

Start Date: 5/01/07

End Date: 5/01/09

Abstract

Environmental concern with phosphorus (P) transport in runoff or drainage is equally important as the concern with nitrogen regarding eutrophication or degradation of receiving waters. Numerous fields that have been receiving animal wastes have a high P index in soil-test samples, meaning the soil already has enough P to provide crop nutrients for several years; in some cases for the next 20 or more years. Applying typical animal manure or wastewater based on N requirements means excess application of P compared to crop uptake. If farms continue to apply P in excess of crop needs, it is only a matter of time until more fields are limited to applying P at crop uptake rates or no manure P at all. This project proposes demonstration and evaluation of a struvite crystallizer at a commercial swine farm for recovering P in a product that is relatively easy to dry and transport and could have substantial fertilizer value. The crystallizer was developed at NCSU, but has only been evaluated for swine lagoon liquid at a research farm for a short period. The lagoon also had concentrations which were only about one-third the concentrations in a typical swine lagoon. This project will evaluate a more sustained operation in a commercial environment rather than short tests in a research environment. Removal of P from lagoons will have the most overall benefit for swine farms in North Carolina because of the large number of swine lagoons compared to dairy or poultry. Demonstration, evaluation and further development of the crystallizer on a commercial farm is important to help show the value of this process to farmers in North Carolina and other states, and help them be proactive in managing P. A cost analysis will also be conducted to include installation costs, operating costs, operating returns, and operating performance of the crystallizer, and potential avoided costs or benefits elsewhere on the farm. A discussion of potential economies of size or scale if the unit is used on farms of various sizes will also be included.

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Manure and Nutrient Characterization for Flushed Manure for Use in Design Criteria for Innovative Treatment Technologies

NC Pork Council(7/01/06 - 6/30/07)

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Manure and Nutrient Characterization for Flushed Manure for Use in Design Criteria for Innovative Treatment Technologies

Sponsor: NC Pork Council

Start Date: 7/01/06

End Date: 6/30/07

Abstract

The objective of this research proposal is to measure and characterize the waste and nutrient production from a grow-finish swine facility. Waste term as used in this proposal includes feces, urine and spilled water and feed. Characterization of fresh manure or excreted manure and the associated nutrients, solids, and chemical oxygen demand for designing waste treatment systems is typically based on either data that is often 20-30 years old or based on prediction equations (input minus retention equals excretion) developed mainly with equations derived from the 1998 NRC publication for swine nutrition requirements. There is a lack of modern data on measurement of waste as collected from actual swine production facilities. This information is needed for several purposes, with one need being as the waste characterization information for designing innovative manure treatment systems or potential environmentally superior treatment technologies. The swine nutrition studies that focus on certain nutrients in the diet and the resulting excretion usually do not report the volatile solids content in the manure, and this parameter is typically needed for design of anaerobic digesters used in manure treatment. Other parameters of interest for designing manure treatment systems are the total solids, the total ammonia, the pH and the oxygen demand (biochemical or chemical oxygen demand), and not all of these are normally reported in nutrition studies. In this project, manure collection will be measured for a grow-finish swine facility that has a flush-tank system for flushing manure from the barn. The facility is at a research farm that has a 2,500 gal. collection tank that can collect the flushed waste and be well mixed to get a representative sample. It is difficult to measure flow rates of flushed manure, so a collection tank to collect all of the flush is preferable. Three different flushes over a 24-hr period will be measured separately in order to determine variation with time of day, and this will be performed every three weeks during two grow-out periods of approximately 18 weeks. The benefit of this research is to provide measured values of waste production for design of waste treatment and utilization systems.

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Litter Amendment and Improved Diet Impacts on Broiler Ammonia Emissions and Productivity

US Dept. of Agriculture (USDA)(1/01/06 - 12/31/10)

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Litter Amendment and Improved Diet Impacts on Broiler Ammonia Emissions and Productivity

Sponsor: US Dept. of Agriculture (USDA)

Start Date: 1/01/06

End Date: 12/31/10

Abstract

As part of EPA's effort to regulate emissions of aerial pollutants (e.g., ammonia) from confined animal agriculture, it plans to oversee monitoring of aerial emissions from two broiler farms (houses and litter stockpiles), one in the southeast US. However, data from two broiler farms and from other past and current studies will be inadequate for developing representative emissions factors (e.g., kg/year-animal unit). Most of the available data are short-term (cannot account for age of litter impacts on ammonia emissions) and intermittent (do not capture the day-to-day variability); also, they do not account for the impact of remediation measures on reducing aerial emissions. Further, there are no US data on emissions from litter stockpiles. This research will substantially add to the: (i) knowledge required to develop emission factors from broiler houses receiving different treatments (remediation measures), (ii) information on benefit/cost of different treatments, and (iii) knowledge required to develop emission factors from stockpiled litter stored using different methods. This study will monitor ammonia emissions, in-house ammonia concentrations, bird performance (multiple variables), litter nitrogen concentration, and energy use from four treatments applied to commercial broiler houses, namely, control, alum treatment, improved diet, and a combination of alum and improved diet over 2 years. Benefit/cost for the alum and improved diet treatments can be used by producers in making productivity and air quality decisions. Four houses will be instrumented to measure ammonia concentrations, and eight will be monitored for bird performance. Ammonia concentrations inside the house and outside each exhaust fan will be monitored continuously with individual gas scrubbers; ventilation rate will be monitored for each fan. Hence, reliable in-house ammonia concentrations and emission factors (including layout periods) will be obtained on 10 flocks (5 flocks/year and litter cleaned out annually). Further, ammonia emissions from seven broiler litter stockpiles will be monitored with each one being continuously monitored with passive tube denuders for 3 months (summer and winter). The stockpiles monitored will include treatments with the highest and lowest litter nitrogen analyses for both caked and cleaned out litter. Emission factors will be developed for stockpiles that are uncovered, covered with tarpaulin, and placed in sheds.

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A Regenerating Scrubber for Reducing Animal House Emissions

NCSU Animal and Poultry Waste Management Center(10/01/04 - 6/30/06)

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A Regenerating Scrubber for Reducing Animal House Emissions

Sponsor: NCSU Animal and Poultry Waste Management Center

Start Date: 10/01/04

End Date: 6/30/06

Abstract

Animal production has the potential to create substantial air pollution by releasing ammonia, particulate matter (PM), and other pollutants into the atmosphere. Methods to reduce air pollution from animal feeding operations by sprinkling oil, using ionizers to increase settling of dust, or by using filters and scrubbers have not been widely accepted due to cost, management, or technical constraints. We propose a novel, regenerating scrubber with a continuously moving, filter belt operated in both wet and dry modes, for removing ammonia, PM, and hydrogen sulfide (H2S); hence, the scrubber could also be effective in reducing odor. In the wet mode, the filter belt soaked in boric acid solution would remove PM, ammonia, and H2S and then be cleaned in a trough of dilute boric acid solution before recirculating through the air stream to remove more pollutants. In the dry mode, more appropriate for high PM concentrations (e.g., broiler house), the PM trapped on the dry filter belt surface would be continuously cleaned at the ends by nylon brushes. Selection of suitable filter material for both wet and dry operations that maximize pollutant trapping and minimize pressure drops will be made through laboratory trials. The wet scrubber will be evaluated for treating exhaust air from the pit ventilation fan in a swine finishing barn. Both wet and dry scrubbers will be evaluated in a naturally-ventilated broiler house. In addition to evaluating the scrubber?s effectiveness under different conditions, information gained will be useful in scaling up the system for use with larger fans. It may be economically and technically feasible to retrofit existing ventilation systems with the simple and compact scrubber.

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Determining Plant-Available Nitrogen in Hog Anaerobic Lagoon Effluent Applied with Traveling Gun and Drag Hose Systems

NCSU Water Resources Research Institute(6/01/05 - 12/31/06)

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Determining Plant-Available Nitrogen in Hog Anaerobic Lagoon Effluent Applied with Traveling Gun and Drag Hose Systems

Sponsor: NCSU Water Resources Research Institute

Start Date: 6/01/05

End Date: 12/31/06

Abstract

Nearly all of the hog waste in North Carolina is treated in anaerobic lagoons and then land-applied on forage or cropland using one or combination of irrigation systems such as traveling gun, center pivot, solid set, or drag hose. Since the lagoon effluent is rich in nutrients such as nitrogen (N), its application rate is regulated to reduce the potential for water pollution. However, availability of N in the effluent is reduced due to ammonia and nitrous oxide (N2O) emissions during or after land-application as well as only partial mineralization of organic N. The NC Dept. of Agriculture and Consumer Services stipulates that only 50% of total N is plant-available N (PAN) which forms the basis for regulating effluent application. However, in addition to lacking an empirical basis, the PAN coefficient does not account for the impact of application using different irrigation methods on N availability. Since ammonia emission increases with turbulent mixing with air, ammonia loss may be higher with the traveling gun (35% of total N within 48 h of application; Sharpe and Harper, 2002) vs. the newer though increasingly popular drag hose system. However, due to lack of ammonia loss data for the drag hose and availability of only limited data for the traveling gun for North Carolina, using the present PAN coefficient may result in underprediction of N loadings with the drag hose and overprediction of N loadings with the traveling gun. Hence, there is need to quantify PAN coefficients for the traveling gun and drag hose systems by measuring seasonal ammonia emissions (during and after land application), and accounting for N2O losses and partial organic N mineralization. Ammonia emissions will be measured for four applications (2 summer, spring, and fall) with the integrated horizontal flux method in which ammonia concentrations will be measured using passive, paired-tube denuders (Schjoerring et al., 1992). Ammonia losses will also be measured during application using catch cans containing acid solution. Nitrous oxide emissions being minor in magnitude and being expensive to measure will be taken into account, based on published literature. Since organic N is a minor component (¡Ü20%) of effluent N and mineralization studies are expensive and time-consuming, 50% organic N will be assumed to be available for crop uptake based on professional judgment (Hatfield et al., 1998).

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