Lara B. Moody

Vegetative Treatment Systems for Open Feedlot Runoff: Project Design and Monitoring Methods for Five Commercial Beef Feedlots

A project to demonstrate, implement, and model non-basin technologies for open beef feedlot runoff at five commercial locations is in progress. The investigation will evaluate through field monitoring the performance of these technologies. This information will be used to address whether the systems are feasible alternatives to traditional basin technologies and used to assess non-basin computer models for planning and design of future systems. The non-basin technologies demonstrated in the study include either a vegetated treatment area (VTA) or a vegetated infiltration basin (VIB) in combination with a VTA. The paper will cover the experimental design, monitoring equipment, and methodologies established to meet the project’s objectives. The objectives of the experimental design will be to quantify contaminant concentrations and annual mass flow of nutrients from treatment areas receiving settled feedlot runoff. Results will be compared to potential annual control attainable with traditional containment systems. Monitoring equipment and methodologies discussed in the paper will cover the following: 1) measurement of the quantity and quality of effluent leaving the solids settling basin (entering the treatment area), 2) measurement of the quantity and quality of runoff leaving the receiving treatment area below the settling basin, 3) measurement of the groundwater quality beneath the receiving treatment area, and 4) if applicable, measurement of receiving stream water quality upstream and downstream of the site.

Ammonia Emissions from Broiler Houses in the Southeastern United States

Continuous monitoring of ammonia (NH3) emissions from two mechanically ventilated commercial broiler houses located in the southeastern United States was performed during a one-year period over 2005-2006 as a joint effort between Iowa State University and the University of Kentucky. Ammonia concentrations were measured using Innova 1412 photoacoustic NH3 monitors. Ventilation rates in each house were measured continuously by monitoring the building static pressure and operational status of all ventilation fans in conjunction with individual performance curves developed and verified in situ using a Fan Assessment Numeration System (FANS) unit. Expressed in various units, NH3 emissions from the two broiler houses over the one-year production period were of the following values: a) 35.4 g per bird marketed (77.9 lb per 1,000 birds marketed), including both grow-out (50-54 d per flock) and downtime (12-25 d between flocks) emissions; b) annual (365-d) emission of 4.63 Mg (5.1 US tons) per house, including both grow-outs and downtime; c) maximum grow-out daily emission of 30.6 kg/d-house (67.4 lb/d-house) for one house and 35.5 kg/d-house (78.2 lb/d-house) for the other; d) mean grow-out daily emission of 14.0 ± 9.1 ( S.D.) kg/d-house; e) mean downtime daily emission of 8.8 ± 8.3 kg/d-house. Flocks on new bedding had a lower emission rate of 12.4 ± 9.4 kg/d-house, as compared to 14.5 ± 8.9 kg/d-house for flocks on built-up litter. The NH3 emission factor of 35.4 g/bird marketed from this study is substantially lower than that cited by US EPA of 100 g/yr-bird (the US EPA yr-bird unit is equivalent to bird marketed).

Performance of Six Vegetative Treatment Systems for Controlling Runoff from Open Beef Feedlots in Iowa

Beef feedlots of all sizes are looking for more cost-effective solutions for managing feedlot runoff. Vegetative treatment systems (VTSs) are one potential option that has been proposed. Iowa State University (ISU) has monitored the performance of six VTSs on open beef feedlots throughout Iowa since 2006. These feedlots have interim, National Pollution Discharge Elimination System (NPDES) permits that allow the use of VTSs to control and treat feedlot runoff. As part of the permit requirements for these feedlots the effluent volumes, nutrient concentrations, and nutrient masses exiting each component of the VTS were monitored. This paper describes the VTSs and monitoring methods used in this study and evaluates the effectiveness, in terms of both effluent concentration and nutrient mass transport reductions, of each system. During the three-year monitoring period, results have shown that VTSs are capable of reducing the nutrient mass exiting the VTSs by 65 – 99% as compared to a settling basin only system, with performance varying by both site and year. In addition to overall mass transport reductions, nutrient concentrations were also reduced, typically reduced by 50-90%, during treatment. Furthermore, monitoring results have shown a consistent improvement in system performance during the three years of the study. Much of this improvement can be attributed to improved management techniques and system modifications that addressed key performance issues.

Quantification of Particulate Emissions from Broiler Houses in the Southeastern United States

Emissions of total suspended particulate (TSP), particulate matter with aerodynamic diameters = 10 µm (PM10), and = 2.5 µm (PM2.5) were continuously monitored at two mechanically ventilated broiler houses in the southeastern United States. Monitoring was performed over a one-year period during 2005-2006 as a joint effort between Iowa State University and the University of Kentucky. Tapered Element Oscillating Microbalances (TEOMs) were used to measure three species of particulate matter (TSP, PM10 and PM2.5). Ventilation rates were measured continuously by monitoring building static pressure and operational status of ventilation fans in conjunction with individual performance curves developed and verified in situ using a Fan Assessment Numeration System (FANS) unit. The magnitude of the TSP, PM10 and PM2.5 emissions are reported as a) annual house total emission and b) on a per 1,000 birds marketed basis. These emission values are: a) 785 kg (1,731 lb) TSP, 330 kg (727 lb) PM10, and 32.5 kg (71.7 lb) PM2.5 per house per year and b) 6.03 kg (13.3 lb) TSP, 2.52 kg (5.56 lb) PM10, and 0.25 kg (0.55 lb) PM2.5, per 1,000 birds marketed. Bird age is the predominant factor influencing particulate emissions. An empirical equation is presented that relates emissions to bird age for the monitored broiler houses. The use of a daily emission factor is not advised for broiler production systems or others in which substantial progressive animal growth occurs over time. The use of emissions per 1,000 birds marketed more realistically expresses emissions and allows for improved emissions inventory tracking.

Greenhouse Gas (GHG) Emissions from Broiler Houses in the Southeastern United States

Greenhouse gas (GHG) emissions, including carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), from broiler houses located in the southeastern United States were continuously monitored over a one-year period. The birds were grown to 52 days of age at an average stocking density of 11.8 birds/m2 (1.1 birds/ft2). Methane and CO2 emissions were measured in two broiler houses while N2O emissions were measured in one house. Carbon dioxide and N2O concentrations were measured using a photoacoustic multi-gas analyzer and CH4 concentrations were measured using a dual-channel methane/non-methane-hydrocarbon (NMHC)/total hydrocarbon analyzer with dual flame ionization detectors. Ventilation rates in each house were continuously calculated by monitoring the building static pressure and operational status of all ventilation fans in conjunction with individual fan performance curves developed and verified in situ using a Fan Assessment Numeration System (FANS) unit. Annual CO2 emissions measured from the two broiler houses averaged 606 Mg (668 US tons) per house. On a marketed bird basis the CO2 emissions averaged 4.64 Mg (5.49 US tons) per 1,000 birds marketed. Annual CH4 emissions averaged 445 kg (982 lbs) per house, or 3.41 kg (7.52 lbs) per 1,000 birds marketed. Annual N2O emissions measured from one broiler house was 225 kg (496 lbs) per house, or 1.72 kg (3.8 lbs) per 1,000 birds marketed. The CO2 equivalents of the CH4 and N2O emissions were, respectively, 85.3 kg (188 lb) and 512.6 kg (1,128 lb) per 1,000 birds marketed. Hence the total CO2 equivalent GHG emissions for the broiler operations monitored in this study were 5.238 Mg per 1,000 birds marketed, with 88.6% contributed by CO2.

Effect of Anaerobic Digestion on Manure Characteristics for Phosphorus Precipitation from Swine Waste

Swine production facilities today are larger in size and are concentrated in smaller geographical areas than they were two decades ago. Additionally, there is an increasing trend to base manure land application rates on crop phosphorus requirements rather than crop nitrogen requirements alone. These factors have resulted in a need to find a feasible method for removing phosphorus from swine waste prior to land application. Economically concentrating and transporting excess phosphorus to phosphorus deficient cropping areas would benefit the current production scheme. Forced precipitation of phosphorus as struvite (MgNH4PO46H2O) is an option for phosphorus concentration and removal. Economic feasibility of phosphorus precipitation improves when reactive phosphorus represents a high percentage of the total phosphorus in slurry, and when a limited amount of chemical amendment is required for the precipitation reaction. In this study, anaerobic digestion of swine slurry increased reactive phosphorus (PO43-) and magnesium ion (Mg2+) in solution by 26% and 254%, respectively. Additionally, during phosphorus precipitation experiments, PO43- removal and reduction efficiencies were greatest in the tests performed with anaerobically digested swine slurry.

Development of a Bench-Scale Air Sparged Continuous Flow Reactor for Struvite Precipitation from Two Different Liquid Swine Manure Storage Systems

Forced precipitation of struvite (MgNH4PO4 . 6H2O) can reduce dissolved reactive phosphorus (DRP) in swine manure slurries. Optimization of this process requires that the swine manure slurry pH be increased, that magnesium be added, and that sufficient reaction time be allowed for struvite precipitation. To gather data that could be used for a full-scale continuous-flow struvite precipitation reactor, a bench-scale (14-L) continuous flow reactor was designed, constructed, and tested. The bench-scale reactor used air sparging for both pH adjustment and mixing, used a peristaltic pump to continuously inject magnesium chloride (MgCl2 . 6H2O), and was operated at a 10-min hydraulic retention time. The bench-scale system provided a 95% reduction of DRP in swine manure slurry collected from a concrete storage tank with a permeable cover, and a 78% reduction of DRP in swine manure slurry collected from a shallow under floor pit collection system. A bench-scale up-flow clarifier was designed, constructed, and tested for continuous flow separation of the precipitated struvite in order to provide total phosphorus (TP) removal. The up-flow clarifier was unable to continuously settle struvite particles formed in the bench-scale reactor and provided no significant TP removal through the system. The implication of this work for full-scale systems is discussed.

Effect of Ultrasonic Pretreatment on Methane Production Potential from Corn Ethanol Coproducts

This article addresses the biochemical methane potential (BMP) production from anaerobic digestion of corn-ethanol coproducts including dried distiller grain with solubles (DDGS), distillers wet grains (DWG), thin stillage, and condensed distillers solubles (CDS) as well as evaluating the effects of ultrasonic pretreatment on methane production from these feedstocks. Ultrasonic pretreatment was applied with three amplitude settings of 33% (52.8 µmpp), 66% (105.6 µmpp), and 100% (160 µmpp) as well as five time settings (10, 20, 30, 40, and 50 s) to each of the four coproducts prior to conducting benchtop BMP trials. Ultrasonic pretreatment reduced mean particle size of DDGS and DWG by 45% and 43%, respectively. Without ultrasound pretreatment, CDS had the highest methane production potential (407 mL g-1 VS added) compared to the other coproducts. Ultrasonic pretreatment of DWG co-products (DDGS and DWG) resulted in greater increases in methane production than on liquid coproducts (CDS and thin stillage). Methane yields were increased by 25% and 12% for the ultrasound pretreated DDGS and DWG, respectively, compared with untreated samples. An energy balance for the DWG, thin stillage, and CDS coproducts indicated that ultrasonic pretreatment required more energy than was generated by the process in terms of additional biogas production. However, an energy balance for ultrasonic pretreatment of DDGS provided 70% more energy than was required to operate the ultrasonic unit.

Performance of a Pilot-Scale Air Sparged Continuous Flow Reactor and Hydrocyclone for Struvite Precipitation and Removal from Liquid Swine Manure

The objective of this research was to test a pilot-scale air sparged tank reactor (ASTR) and the ASTR in combination with a hydrocyclone (called the pilot-scale ASTR-hydrocyclone system) on two swine manure slurries for struvite-based (MgNH4PO4-6H2O) phosphorus removal and recovery. The pilot-scale ASTR system operated at flow rates of 80 to 115 L/min and was based on the bench-scale design from Shepherd et al. (2007). The ASTR effluent was processed using a hydrocyclone separator for struvite separation and total phosphorus (TP) recovery. The pilot-scale ASTR-hydrocyclone system provided a 92% reduction of dissolved reactive phosphorus (DRP) in manure slurry from a swine finishing facility concrete storage tank and a 91% reduction of DRP in manure slurry collected from a swine finishing facility deep-pit under floor collection system. The pilot-scale ASTR-hydrocyclone system removed 18% of TP in swine manure from a concrete storage tank and 9% to 14% of TP in swine manure slurry from a deep-pit under floor collection system. The low TP recovery was attributed to the hydrocyclones inability to provide effective struvite separation as operated. Full-scale economics and implementation of the tested struvite-based phosphorus removal is discussed. A case study of a typical Iowa deep-pit swine production facility (10,000 head/year) indicated that the annual cost of struvite-based phosphorus removal using this system would be approximately

Evaluation of Laboratory Biochemical Methane Potentials as a Predictor of Anaerobic Dairy Manure Digester Biogas and Methane Production

8.88/finished pig or