Reducing Feed’s Environmental Footprint: Where Are the Opportunities?

Working with animal food industry members and stakeholders up- and down-stream in the supply chain, the Institute for Feed Education and Research (IFEEDER) developed a ‘Sustainability Road Map’ to support the U.S. animal food industry as it pursues continuous improvement on impacts important to industry members and their customers. For IFEEDER and the American Feed Industry Association (AFIA), sustainability is defined and managed by each individual organization to deliver measurable, continuous improvements on the impacts related to people, planet and governance that are most important to them and their stakeholders

Reducing Feed’s Environmental Footprint: Where Are the Opportunities?

Working with animal food industry members and stakeholders up- and down-stream in the supply chain, the Institute for Feed Education and Research (IFEEDER) developed a ‘Sustainability Road Map’ to support the U.S. animal food industry as it pursues continuous improvement on impacts important to industry members and their customers. For IFEEDER and the American Feed Industry Association (AFIA), sustainability is defined and managed by each individual organization to deliver measurable, continuous improvements on the impacts related to people, planet and governance that are most important to them and their stakeholders

Concentration and Extraction of Phosphorous from Swine Manure Slurries (as Struvite)

Excessive loading of phosphorus (P) onto agricultural lands has been recognized as a threat to surface water quality. Forced precipitation of struvite (MgNH4PO4•6H2O) from animal waste slurries prior to land application can reduce dissolved reactive P levels in manure slurries. It also offers the potential to recover excess phosphorus from manures and move it to cropping areas that require phosphorus fertilizer inputs. Past work indicates that ~90% of the soluble phosphorus can be concentrated into a precipitate following chemical amendment. This study will provide important information regarding the feasibility of phosphorus recovery as a means of balancing swine manure nutrient content with crop needs. Given the expanding regulations regarding phosphorus management, it is important to develop and test phosphorus management strategies. The sustainability of many animal operations in their current locations will depend upon their ability to meet new regulations requiring phosphorus management as well as nitrogen management

Anaerobic Digestion System Selection for Croatian Swine Manures

Interest in the anaerobic digestion (AD) of swine manures and slaughter waste continues to increase due to the potential to produce renewable energy in the form of biogas and due to the expanding market for carbon credits around the world. This paper provides an analysis of the anaerobic digestion types and operational schemes that are best suited to Croatian swine production. In addition, it proposes a methodology to optimize system selection and design by predicting biogas production quantity and quality based on the use of biochemical methane potential (BMP) assays followed by the use of pilot-scale reactors to make final system selections and estimate system hydraulic retention times (HRT) for the selected system design. A review of reactor configurations that are promising for swine manure and slaughter waste digestion suggests that a mesophilic, continuously fed AD system be investigated to digest a mix of Croatian large-scale swine manure and slaughter waste

A Review of Available Resources on Anaerobic Digestion Technologies

Anaerobic digestion of manures provides multiple environmental benefits for animal feeding operations including odor reduction, green house gas emission reduction, and production of a renewable energy source. This paper provides an overview of information sources available in the United States regarding anaerobic digestion of manures. Selection and implementation of an optimal anaerobic digestion system for a given farm requires significant research regarding digester type, biogas production potential, biogas collection and handling, construction cost estimates, and operation and maintenance cost estimates. Practical information concerning anaerobic digestion is dispersed through a number of sources in the U. S. Information sources in this review include items from the federal and state government agencies, land grant universities, and non-profit organizations. The reviewed items provide information related to methane recovery technologies on U.S. concentrated animal feeding operations, economics of biogas production for on-farm heating, case studies of U.S. animal manure digesters, and various other anaerobic digestion resources. A concise review of available US information sources regarding the anaerobic digestion of animal manures is provided to assist in the decision making process concerning selection and implementation of manure anaerobic digesters

The Use of the Soil-Plant-Air-Water Model to Predict the Hydraulic Performance of Vegetative Treatment Areas for Controlling Open Feedlot Runoff

Several Iowa beef feedlots have interim, National Pollution Discharge Elimination System (NPDES) permits for vegetative treatment systems (VTS) to control and treat feedlot runoff. In Iowa, performance of these systems is predicted for permitting purposes using either the Iowa State University-Vegetated Treatment Area (ISU-VTA) Model or the Iowa State University -Vegetated Infiltration Basin/Vegetated Treatment Area (ISU-VIB/VTA) Model. For an Iowa NPDES permit, these systems must be shown through modeling to have equal or better performance than a conventional runoff containment basin on the basis of median nutrient mass released over 25 years. Modeling is also a useful design tool for both Concentrated Animal Feeding Operations (CAFOs) and non-CAFO sized operations wishing to utilize VTS systems. Field-scale VTS performance monitoring conducted over the past two years by ISU has shown that the current ISU models do not accurately predict actual hydraulic performance at the monitored VTSs. The ISU models are being revised to improve their performance. Along with improving the ISU-VTS model performance, other modeling alternatives are being investigated. The Soil-Plant-Air-Water (SPAW) model is one possible alternative for modeling the hydraulic performance of a VTA. For this paper, the SPAW predicted performance was compared to monitoring results at four VTAs located in Iowa. Two different methods were used to model the VTA performance, the first method utilized the field module of SPAW; this method was found to have Nash-Sutcliffe modeling efficiencies ranging from 0.16 to 0.57. At all locations, the SPAW model underestimated the amount of release that occurred from the VTAs. The second modeling method utilized the pond module of SPAW, for this method the Nash-Sutcliffe modeling efficiencies ranged from 0.26 to 0.83. Again, the SPAW model underestimated the cumulative volume of effluent released from the VTAs

The Use of Phosphorus Sorption Isotherms to Project Vegetative Treatment Area Life

Beef feedlots of all sizes are looking for cost-effective solutions to manage feedlot runoff. Vegetative treatment systems (VTSs) are a potential option. VTSs consist of a solids settling structure followed by additional treatment components, such as vegetative infiltration basins (VIBs) and/or vegetative treatment areas (VTAs) that use soil and vegetation to treat nutrients in the applied runoff. Investigations have shown that VTSs can provide a cost-effective means of controlling feedlot runoff; however, their sustainability and life expectancy have not yet been determined. Thus, the objective of this work is to evaluate, based on the VTA’s ability to sorb and utilize phosphorus, the expected phosphorus sink life of VTSs on beef feedlots in Iowa. In doing so, we evaluated three things: (1) phosphorus removal with vegetation harvest, (2) the extent of vertical redistribution of phosphorus in the soil profile, and (3) if a mass balance approach was capable of predicting changes in soil test phosphorus. Vegetation harvest removed 6% to 16% of the applied phosphorus, and a P mass balance did an adequate job of predicting the significant increases in soil P test concentrations. Deep soil cores (1.2 m) showed that phosphorus accumulation tended to be limited to the top 0.3 m but that vertical migration was increasing. Based on this success, we proposed a P mass balance and soil sorption model to project VTA life expectancy and evaluated the sensitivity of the estimated life to different design and management alternatives. The sensitivity analysis showed that phosphorus sorption capacity and loading rate were important, but the critical depth of the soil that can be saturated has the largest impact on VTA life

Modification of the Iowa State University-Vegetative Treatment Area Model

Vegetative Treatment Systems (VTSs) are currently being used at several open beef feedlots across Iowa as an alternative to traditional feedlot runoff containment systems. There are two types of VTS: a VTA system which is comprised of solids settling basin (SSB) followed by a vegetative treatment area (VTA), and a VIB-VTA system which is comprised of a solids settling basin followed by a vegetative infiltration basin (VIB) and a VTA. Iowa State University developed two computer models to simulate VTS performance. When model predictions were compared with data collected from four Iowa sites, the models were found to under predict the VTA outflow, VIB outflow, and nutrient concentrations in the SSB outflow. This paper focuses on the modifications made to the Iowa State University VTA model. To identify the problems with the model, the graphical and numerical outputs were examined for values that were either not reasonable or did not fit the expected behavior of the system. Three major problem areas were identified in the VTA model: an extremely high rate of water removal from the VTA, incorrect calculation of soil moisture, and incorrect tracking of the water table (especially in high water table situations). Each of these problems was isolated and the code controlling this function of the model was examined. Potential solutions were tested to see if they accurately simulated VTS behavior. If successful, the solutions were then implemented. These modifications and their impact on model performance are discussed in this paper

Physical and Chemical Properties of Runoff Effluent from Beef Feedlots in Iowa

Beef feedlot runoff is a potential environmental contaminant. As such, it should be managed properly to preserve water quality. Primary treatment of feedlot runoff often relies on sedimentation techniques; thus, accurate knowledge of feedlot runoff physical properties is required. This study characterized the physical and chemical properties of runoff effluent from earthen and concrete beef feedlots in Iowa with the objective of providing the necessary information to improve solid settling basin design and performance. Results, although not statistically significant (p = 0.11), indicated that solids in runoff from concrete lots tended to settle more slowly than solids from earthen lots. Particle size distribution and particle density measurements indicated that the poorer settleability of concrete lot runoff was primarily caused by lower particle densities: 1.47 ±0.17 g cm-3 (average ± SD) for concrete lots as compared to 1.89 ±0.11 g cm-3 for earthen lots. Runoff composition was analyzed before and after settling to relate nutrient reduction to solids removal. Results indicated an average of 41 g total Kjeldahl nitrogen per kg total solids and 16 g total phosphorus per kg total solids were removed during settling

Physical and Chemical Properties of Runoff from Beef Feedlots in Iowa

Beef feedlot runoff is a potential environmental contaminant. As such, its proper management is required to preserve water quality. Primary treatment of feedlot runoff often relies on sedimentation techniques, thus accurate knowledge of feedlot runoff physical properties is required. This study characterized the physical and chemical properties of runoff effluent from earthen and concrete beef feedlots in Iowa with the objective of providing the necessary information to improve solid settling basin design and performance. Study results indicated there was a difference between the settleability of runoff from earthen and concrete lots. Particle size distribution and particle density measurements indicated that the poorer settleability of concrete lot runoff was primarily caused by lower particle densities, 1.47±0.17 g/cm3 for concrete lots as compared to 1.89 ± 0.11 g/cm3 for earthen lots. Runoff composition was analyzed before and after settling to relate nutrient reduction to solids removal. Results indicate an average of 41 g-TKN/kg-TS and 16 g-TP/kg-TS removed by settling