Reducing the Environmental Impact of Food Animal Production

<p>NON-TECHNICAL SUMMARY:<br/> Demand for food and especially for animal products is expected to double in the coming decades due to population increases and expected higher living standards of parts of the world. Resources needed to produce these products are under increasing stress imposing limits on soil, water, nutrients and energy availability and quality. At the same time, public interest in how our food animals are raised is also increasing, with questions about food safety, animal welfare, organic methods, environmental pollution, costs, and jobs. Potential benefits of recent and current research have not been fully integrated into stakeholder tools because of the complex interactions of the production systems, management systems, and social systems in which they function. This project will not only continue to develop the needed tools and techniques but will also
work to integrate the results of these tools with existing tools to generate meaningful options with expected impacts on production, emissions, and resource consumption. Results will be useful to the general public's understanding of our food system as well as to policy makers and producers asking questions about what technologies are available, what will happen if a specific technology or mix of technologies is implemented.
<p>APPROACH:<br/> For new waste treatment technologies to be successful, all aspects of the system must be addressed. Existing and alternative treatment concepts, those developed in the laboratory and those introduced by others, will be assessed based on ease of operation, potential conversion efficiencies, energy consumption, market considerations for potential products, and fate of nutrients. This project will use various techniques to develop models of the confined animal feeding industries in North Carolina and the southeast United States that will help identify ways to reduce the cumulative ecological impact of these operations. Life cycle assessment, GIS, mass and energy balances are some of the tools that will be used to integrate the ecological and environmental considerations with the business and livelihood of individual producers and companies. Where possible,
data from actual feeding operations and manure management systems will be used to describe the movement and transformation of nutrients through an animal operation. Where necessary, data from published studies or averaged data from handbooks and databases will be used. Through the model development process, gaps in knowledge and data will become apparent and efforts will be directed toward filling those gaps. Data will be analyzed with appropriate statistical tools for significance; process models will be developed from these data to predict performance and emissions of pollutants. These process models will be used to develop LCA and GIS evaluations of the impact of various deployment schemes of the different technologies. Results and implications will be shared in appropriate research and professional journals, classroom and distance education modules, and extension activities of
associated faculty.
<p>PROGRESS:<br/> 2012/10 TO 2013/09Target Audience: Research scientists and engineers as well as professionals in the animal production and nutrient management fields. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Results were published in scientific journals and will be incorporated into appropriate courses. What do you plan to do during the next reporting period to accomplish the goals? Plans for the next reporting period include begnnng the development of a protocol to synthesize the mpacts of adopting various manure management and resource recovery operations. This protocol wll include technical performance, economic expecatons, analysis of the impacts on the larger food animal system, and analyss of the
expected adopton rates and the barriers to adoption.
<p>PROGRESS:<br/> 2011/10/01 TO 2012/09/30OUTPUTS: Ammonia emission from poultry houses is a major air quality concern. In poultry litter, uric acid converts to urea which hydrolyzes to NH3; a fraction of NH3 protonates to ammonium. Moisture content (MC), dissociation constant, and Henry's law constant affect NH3 partitioning among solid, liquid and gas phases. The dissociation constant (Kd) and Henry's Law constant (Kh) that are so well known for dilute aqueous solutions may not apply to broiler litter which has much higher ionic concentration. The research quantified Kd, Kh and ammonia sorption at different MC in broiler litter in replicated lab experiments. Dissociation constant in litter slurry was 1.02E-10, 20% of the dissociation constant in aqueous solution, which may be due to ammonia / ammonium adsorption and reduced activities of the dissolved ions. Henry's Law
constant (0.0158 atm/M) in litter slurry was 4% lower than Kh in dilute aqueous solution. Ammonia sorption increased with MC from 0% to 25% due to Van der Waals force and hydrogen (H) bonding; maximum ammonia-nitrogen sorption was 4,230 mg/kg at 25% MC (dry-basis) and then decreased with increasing MC up to 55%, which may be due to the decrease of H bonding. Litter at 0% MC adsorbed more than 2,800 mg/kg of ammonia-nitrogen, more than sorbed by litter with MC greater than or equal to 45%. PARTICIPANTS: Sanjay Shah of North Carolina State University collaborated on this project. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
<p>PROGRESS:<br/> 2009/10/01 TO 2010/09/30OUTPUTS: Many of the manure and sludge samples cannot be accurately analyzed for solids components because they are too thick to flow, measure and filter according to conventional methods. Work was begun on developing new laboratory procedures using a centrifuge to help separate the solid and liquid fraction for better handling and analytical results. Although such procedures have been used in the lab, there is no documentation of the procedure, results or limitations in the literature. Work also began on experiments to determine the dynamic interactions of ammonia and poultry litter. How ammonia partitions among air, liquid and solid phases present in poultry litter impacts how we should design strategies to reduce release of reactive nitrogen from these systems. PARTICIPANTS: Nothing significant to report during this reporting
period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
<p>PROGRESS:<br/> 2008/10/01 TO 2009/09/30OUTPUTS: Work continued on developing an integrated approach to measuring and improving sustainability of animal production and manure management systems. The initial attempt at the life cycle inventory of swine feed production, based on literature values found significant variation in values and in the way data were reported; a more rigorous investigation of primary sources is needed. Verification of the integrity of sludge samples obtained with a revised sampler was completed. Results confirm that with careful operation of the device, discreet samples from six inch thick layers can be collected without interference. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
<p>PROGRESS:<br/> 2007/10/01 TO 2008/09/30OUTPUTS: Work continued on developing an integrated approach to measuring and improving sustainability of animal production and manure management systems. Life cycle assessment (LCA) has been selected as the basis of the integrated approach. The first step in LCA is the life cycle inventory (LCI) of swine feed production, which has been initiated in 2008. The analysis of biosolids disposal with respect to biofuel feedstock production at the local wastewater treatment plant was completed in 2008. Modeling results suggest a strong impact on crop yields to both irrigation and fertilization. The modeling approach considers other aspects of the farming component at the WWTP since such an operation does not only consider yield and income in decision making. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET
AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Not relevant to this project.
<p>PROGRESS:<br/> 2006/10/01 TO 2007/09/30Work began on developing an integrated approach to measuring and improving sustainability of animal production and manure management systems. A project was initiated with the City of Raleigh to develop a spreadsheet tool that will help determine the best use of the farm land associated with the Neuse River Wastewater Treatment Plant with respect to bio-energy crop production. Work was also initiated to develop ways to precisely sample and measure the bottom sludge component of animal waste lagoons with the goal of improving operation and cleanout procedures. We have developed a sampler that can take undisturbed samples from any depth in a lagoon within approximately a six inch span.
<p>PROGRESS:<br/> 2005/10/01 TO 2006/09/30Work continues on development of the underfloor belt system that separately recovers feces and urine and on utilization of these resources. Work was completed on a project funded by the Animal & Poultry Waste Management Center. The objective of this research was to evaluate the feasibility of stripping ammonia for recovery from the waste liquids collected by the belt system. Bench-scale experiments were conducted to evaluate the effect of different operating conditions, including pH, temperature and air flow rate on ammonia stripping in relation to the characteristics of the liquid waste stream. A countercurrent stripping tower process was tested at laboratory scale. In a countercurrent system, liquid enters at the top of the tower and clean air enters at the bottom. The air exiting the reactor at the top is in contact with the
highest concentration in the liquid, and therefore has the highest equilibrium concentration of NH3. The liquid exiting the reactor at the bottom of the column is in contact with the cleanest air, and will therefore have the lowest equilibrium concentration in the liquid. Operating conditions of pH 7.6 - 10.5, temperatures of 45 - 64 C (113-147F), and gas:liquid flow volume ratio (G:L) of 80 were evaluated. Adjustment of pH was accomplished by addition of commercial lye (approx. 100% NaOH). Lye was used to avoid scaling problems associated with lime addition. The system was operated as a batch process. Liquid was recirculated, and removal efficiency vs. time of operation was determined by analysis of ammonia in the liquid stream. Liquid volumes were monitored to account for water evaporation. Liquid flow rate was set at 16 gal/hr (1.0 L/min), which is equivalent to a loading rate of 1.35
gal/ft2-min (5.5 cm/min). Higher liquid flow rates caused foaming and liquid build-up in the bottom of the column. A gas flow rate of 2.8 cfm (80 L/min) was used in the tests. Results demonstrated up to 0.8 g N per minute could be removed by air stripping, depending on the pH and temperature used in the process. Calculations suggested that a continuous flow system could improve efficiency once operational parameters are established. Since additional chemicals on a farm are always a concern, the required pH adjustment could be reduced by using a higher air flow rate and / or higher temperatures.
<p>PROGRESS:<br/> 2004/10/01 TO 2005/09/30Alternative Natural Technologies, Inc. (ANT) Sequencing Batch Reactor (SBR) was one of the projects selected for demonstration and evaluation as a candidate Environmentally Superior Technology for swine manure management under an agreement between the North Carolina Attorney General and Smithfield Foods, Premium Standard Farms and Frontline Farmers. The main objective of the technology performance verification was to determine the effectiveness of the system in terms of conversion or removal of solids, organic matter, nutrients, and metals. The ANT Sequencing Batch Reactor (SBR) wastewater treatment system was installed to treat half of the wastewater from 4,200 pigs in six confinement buildings. Whole wastewater with no solids separation is pumped into the reactor at the beginning of a cycle and is treated through several stages:
Fill, React, Waste, Settle, and Decant. During the Fill stage, a portion of the reactor volume is replaced with fresh wastewater. The React stage consists of alternating aerated and non aerated conditions to promote nitrification and denitrification. Excess biomass is removed during the Waste stage while the reactor is mixed. After biomass wasting and a one hour settling period, clarified wastewater is removed from the reactor in the Decant stage and the cycle is repeated. The installation at the Hunt farm did not include a biosolids handling system so the excess biomass was sent to the lagoon as was the clarified wastewater for spray field application. Flow into and out of the SBR system was measured by in-line flow meters. Samples from various points in the system were analyzed for nutrients. Without disposing of biosolids, the SBR system was able to consistently achieve 83%, 64%, and
60% removal of TKN, COD, and suspended solids COD, respectively, under normal loading conditions. Including the planned biosolids handling system, the SBR system removed 90% of TKN, 84% of COD, and 90% of suspended solids COD under normal loading conditions. The major objectives of a project funded by Golden Leaf Foundation were to provide a methodology for conducting a business feasibility analysis for marketing value-added products derived from alternative swine manure treatment systems, to apply that methodology to several products identified with swine waste treatment systems, and to demonstrate the implementation of target costing and value engineering to an example product. The first product of the project was a seven step general problem solving process. Results showed that biomethanol from swine manure in eastern North Carolina might be a successful product if economics could be
improved. The target costing and value engineering system was implemented for biomethanol and several aspects of the production system were identified for improvement.
<p>PROGRESS:<br/> 2003/10/01 TO 2004/09/30Three cycles of hogs have been produced on the prototype under floor belt system for immediate separation of solids as defecated which is the best substrate or input for alternative by-product recovery processes. The belt serves 6 pens for a total of 18 hogs in each cycle. Over three growth cycles, the pigs produced 0.844 kg/hd/d feces at 67.3% moisture and 3.7 L/hd/d urine. Waste characterization showed 39% of the nitrogen and 90% of the phosphorus was in the solids. The overall average daily weight gain of the animals in the study was 0.95 kg/d compared to the industry average of 0.77 kg/d, reflecting fewer days required to reach market weight for the pigs in this study compared to the industry average of 110 to 120 days. This approximately 17% decrease in days on feed represents an important potential economic benefit of the
system. It is unclear to what these benefits can be attributed: improved air quality and lower ammonia, the different ventilation system in the test building, or the extra daily human contact with technicians and students conducting the work. A full scale, commercial installation is required to further evaluate these gains. The important lesson so far is that the pigs did not suffer from the belt system installation. The Carbofil biological reactor is a type of down-draft reactor that uses impellers to entrain oxygen and increase the opportunity for that oxygen to dissolve in wastewater. The oxygen is used for oxidation of organic matter as well as for nitrification. The system flow scheme through an anoxic reactor provides opportunity for denitrification of nitrate formed in the aerobic reactor. A pilot scale reactor was constructed at a swine finishing farm near Faison, NC and
evaluated over an eight week period to establish the potential of the system to efficiently remove ammonia and chemical oxygen demand (COD) from flushed swine wastewater. The odor reduction potential of the system was also evaluated. A total of 16 samples of influent and effluent were taken over the evaluation period and analyzed for chemical constituents. Separate samples were collected on four different occasions near the end of the project and analyzed for odor intensity, irritation intensity, and hedonic tone. Results showed 93% removal of ammonia, 91% removal of soluble Kjeldahl nitrogen, and almost 83% removal of soluble COD. As would be expected in an aerobic treatment system, odor intensity of the full strength effluent from the Carbofil reactor was 18% less than that of the anaerobic lagoon and irritation intensity was 37% lower for the reactor effluent than for the lagoon
effluent. Analysis of diluted samples shows a rapid drop off in odor values in the effluent from the Carbofil reactor that did not occur with the lagoon effluent, suggesting the odor intensity and irritation intensity of the Carbofil reactor effluent are not as persistent as that of the lagoon effluent.
<p>PROGRESS:<br/> 2002/10/01 TO 2003/09/30Data analysis of the project to evaluate the InStream Lagoon Treatment System, a partially aerated lagoon, showed the system lowered the amount of nitrogen to be disposed by 42% compared to what would be expected on a similar farm using a conventional lagoon. Measurements of oxidation-reduction potential and dissolved oxygen indicating that the nitrogen lost was in the form of dinitrogen gas rather than ammonia were supported by analysis of gas samples colleted from the surface of the system. Gas samples were collected over several days and analyzed for dinitrogen and methane. Nitrogen emission data were collected for contamination from the atmosphere during sampling and for dinitrogen stripped from the liquid. Results of the analysis showed biological denitrification produced 150 kg N2 ha-1 d-1 when the aeration system was on and
32 kg N2 ha-1 d-1 when the aeration system was off. These results indicate stripping of dinitrogen was generally not a factor in this partially aerated system but may be an important factor in conventional lagoon systems. Two additional verification tests of solid separation technologies were completed as part of the USEPA Environmental Technology Verification program. Results showed different technologies perform differently and are subject to different problems. Three cycles of hogs have been produced on the prototype under floor belt system for immediate separation of solids as defecated which is the best substrate or input for alternative by-product recovery processes. The belt serves 6 pens for a total of 18 hogs in each cycle. Analysis of the growth data and manure production characteristics will be completed shortly.
<p>PROGRESS:<br/> 2001/10/01 TO 2002/09/30The data collection phase of the project to evaluate the InStream Lagoon Treatment System was completed. Although data analysis will continue, initial analysis shows the system was able to remove more nitrogen than a typical anaerobic lagoon. Measurements of oxidation-reduction potential and dissolved oxygen indicate the possibility that the nitrogen lost was in the form of dinitrogen gas rather than ammonia. Measuring N2 gas emissions from waste treatment systems is difficult because of problems associated with sampling and accurately estimating denitrification. This project supported the development and testing of a gas collection method that keeps atmospheric nitrogen contamination to a low level. Results of laboratory tests show that atmospheric contamination is controlled at a low level and that reliable quantification of
dinitrogen is possible. The first verification test of a technology to separate solids from flushed swine solids was completed as part of the USEPA Environmental Technology Verification program. Results showed the solid bowl centrifuge was able to recover 56% of the suspended solids, 20% of the total nitrogen, and 42% of the total phosphorus in the influent waste stream. Tests of other technologies are in various planning stages. The prototype under floor belt system for immediate separation of solids as defecated which is the best substrate or input for alternative by-product recovery processes is now operational and adjustments are being made to improve its performance. The belt serves 6 pens for a total of 18 hogs. The goal of the current project is to collect all wasted solids including feed in the driest form possible and to obtain immediate separation of liquids to minimize odor
and the conversion of urea in the urine to ammonia. The enzyme for converting urea to ammonia is in the feces so immediate liquid separation will minimize odor and ammonia emissions and provide for a high recovery of wasted nitrogen. Operation and evaluation of the prototype belt system has revealed improvements that can be made in the tracking and slope of the under floor belt, transfer of solids and liquids to treatment and storage units, animal pens including flooring and better feeders and drinking water devices to reduce the liquids and wasted feed collected on the belt.
<p>PROGRESS:<br/> 2000/10/01 TO 2001/09/30Several projects were initiated that will develop or test alternative animal waste treatment and management systems. The project to evalutae the In Stream Lagoon Treatment System was started. This system uses a low energy disk aerator / mixer to enhance oxygen transfer into the liquid and to circulate the contents of the lagoon. Data collected to date shows significant changes in the lagoon with respect to important parameters that show nitrification and denitrification are taking place in this system. Even though the system has been in place for over a year, oxidation-reduction potential, dissolved oxygen concentration, and nitrate concentration were still changing during the late summer and fall months. Oxidation - reduction potential has been as high as 130 mV in several locations around the lagoon and nitrate concentrations
have risen to above 100 mg/L. Analysis of gases collected from several locations in the system show both dinitrogen gas and methane are being generated. Methanogenesis and dentrification are taking place within the system, probably at different depths. The evaluation of a solid separation system and nitrification / denitrification reactor system was also initiated. Flow measurement and sample collection equipment has been ordered and will be installed during the spring. A system of laboratory reactors has been constructed and tested that will allow precise measurement of oxygen added and the measurement and analysis of gases produced by the biological treatment of animal waste. The purpose of this project is to determine the processes involved in the nitrogen removal in systems with low oxygen input.
PROGRESS: 1999/10/01 TO 2000/09/30n/a