Fertilizer Institute

Washington, DC, United States

Fertilizer Institute

Washington, DC, United States

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Moody L.B.,Fertilizer Institute | Burns R.T.,University of Tennessee at Knoxville | Bishop G.,University of Tennessee at Knoxville | Sell S.T.,Iowa State University | Spajic R.,Agrokor Belje
Applied Engineering in Agriculture | Year: 2011

There has been an increasing interest in manure anaerobic digestion; however, economic constraints are still one of the limits to widespread use of the technology in the United States. Co-digestion of manure with other feedstocks has been noted as a way to increase the economic feasibility of animal feeding operation anaerobic digesters via increased energy production potential. A wide variety of materials have been proposed as co-digestion materials, and additional substrates will continue to receive consideration. Biochemical methane potential assays (BMPs) have been reported to provide a "firstcut" evaluation of potential substrates. This article provides specific details about the BMP assay process used by the Agricultural Waste Management Laboratory (AWML) at Iowa State University (ISU) on agricultural materials and by-products, including the assay method and utilization of the results. Additionally, BMP results from 31 samples assayed in the ISU AWML as broader anaerobic digestion research or as service to the industry have been included. Results showed that the high solid content and non-homogeneity of agricultural materials and by-products can increase variability in assay results. The method utilized here helped limit the effects by utilizing volatile solids concentrations instead of chemical oxygen demand to initiate the BMP assays and to normalize the results. The coefficient of variation for the assays performed in triplicate ranged from1.6% to 33% in which the majority was less than 15%. For five of the substrate types analyzed (beef manure, dairy manure, cheese when lactate permeate, food processing marinate, and enzyme process by-product), multiple samples were assayed from different sources. The sample standard deviations indicated that methane production potential could be affected by material source and that BMP assays reported here should only be used as an estimate when considering which types of materials to assay. © 2011 American Society of Agricultural and Biological Engineers.


Spajic R.,Agrokor Belje | Spajic R.,Iowa State University | Burns R.T.,University of Tennessee at Knoxville | Moody L.B.,Fertilizer Institute | And 4 more authors.
Transactions of the ASABE | Year: 2010

Food industry by-products such as spent brewer's yeast and whey from cheese production are being amended with nutrients and used as a feed source in the Croatian swine sector. However, as interest in energy production and anaerobic digestion of animal manures has increased, co-digestion of these materials with manure could improve the economic viability of on-farm digesters. To determine the feasibility of this approach, consideration should be given to whether food industry by-products provide a better economic return as a low-cost animal feed or as an anaerobic digester feedstock. In addition, while slaughterhouse wastes are not used as an animal feed, this article also considers the use of this material as a co-digestion feedstock. The economic information and substrate selection presented in this article are based on by-products available to a swine farm in Croatia and production data from the facility while feeding with by-products. Biochemical methane potential (BMP) assays were used as a fast, inexpensive method to determine the potential methane production rates for the various substrates. Using BMPs, the potential methane production rates for various combinations of spent brewer's yeast, whey, slaughterhouse waste, corn silage, and swine manure were also determined. Results of the BMP assays were used to compare the potential economic return of using the food wastes to produce methane in the digester to the value of these materials as feed ingredients for swine production. Based on live production data, liquid feeding of food industry by-products was calculated to provide a $6.89 savings per finish pig produced over a 90-day period at the Croatian facility. Since the facility produces 14,000 finish pigs every 90 days, this represents a cost savings of $96,000 per turn, or over $307,000 per year considering that the facility finishes 3.2 turns of pigs per year. Using cheese whey or spent brewer's yeast as a co-substrate in the proposed swine manure digester has the potential to provide an additional income via electricity generation of $26,000 and $34,000 over a 90-day period, or $83,000 and $109,000 annually, respectively. These values were based on the value of the substrate, assuming that either a digester or liquid feeding system already existed. Based on the data, the economic return is better when the by-products are used as a feed ingredient. However, if the swine digester is amended with all available co-substrates, including whey, spent brewer's yeast, slaughterhouse waste, and corn silage, the potential additional income is $168,000 per 90-day turn or $538,000 per year. The data presented in this article include substrate characteristics, potential methane production normalized on the basis of mass of substrate volatile solids, estimated electricity generation potential, and economic data. © 2010 American Society of Agricultural and Biological Engineers ISSN 2151-0032.


Sell S.T.,Iowa State University | Burns R.T.,University of Tennessee at Knoxville | Moody L.B.,Fertilizer Institute | Raman D.R.,Iowa State University
Applied Engineering in Agriculture | Year: 2011

Design and construction of full-scale anaerobic digesters that co-digest manure with other substrates, such as food processing wastes, is challenging because of the large number of potential mixtures that can be fed to the digester. In this work we examine the relationship between results from bench-scale methods such as biochemical methane potential assays (BMPs) and sub pilot-scale reactors. The baseline feedstock for this study was beef manure from concrete feedlot pens (open and covered) in eastern Iowa. Additional co-digestion substrates tested were short-fiber cardboard, corn processing wastewater, enzyme processing wastewater and lagoon liquid. Substrates were characterized for total solids (TS), volatile solids (VS), chemical oxygen demand (COD), pH, alkalinity, and ammonia, after which BMPs were conducted on all substrates. Based on the BMP and anaerobic toxicity assay (ATA) results, a mixture was created and evaluated using BMPs and tested in 100-L sub pilot-scale reactors. This study showed that results from BMPs of feedstock co-digestion mixtures accurately estimated the range of methane produced from three 100-L, plug flow reactors. © 2011 American Society of Agricultural and Biological Engineers.


Moody L.B.,Fertilizer Institute | Burns R.T.,University of Tennessee at Knoxville | Sell S.T.,Iowa State University | Bishop G.,Iowa State University
Applied Engineering in Agriculture | Year: 2011

While there has been increasing interest in manure anaerobic digesters during the past decade, economic constraints remain a limitation to widespread use of the technology. Literature has suggested that co-digestion with other available organic co-substrates could increase the economic viability of manure anaerobic digesters by increasing methane production potential. However, co-substrates must be carefully selected to avoid adding complexities to the manure digestion process. Biochemical methane potential (BMP) assays have been reported to provide a good initial evaluation of potential co-substrates, but they are performed under conditions optimized for the microbes, and the co-substrate is assayed under diluted conditions. Anaerobic toxicity assays (ATAs) provide additional information that could be utilized with BMP results to assist with co-substrate selection. An ATA evaluates a substrate's ability to inhibit methane production and thus determine its potential toxicity. This article provides specific details about the ATA process used by the Agricultural Waste Management Laboratory at Iowa State University on potential digester materials, including the assay method and utilization of the results. The two potential digester materials presented in this article provide examples of a toxic and a non-toxic material. Specifically, normalized BMP results indicated that the industry process by-product produced 60 mL CH 4/g VS, and that it was not toxic at material inclusion rates of up to 49%. Conversely, the enzyme process by-product produced normalized BMP results yielding 284 mL CH 4/g VS, but based on ATA results was highly toxic at all inclusion rates. These results clearly indicate the need to thoroughly evaluate co-digestion co-substrates. © 2011 American Society of Agricultural and Biological Engineers.


Andersen D.S.,Iowa State University | Burns R.T.,University of Tennessee at Knoxville | Moody L.B.,Fertilizer Institute | Helmers M.J.,Iowa State University
Applied Engineering in Agriculture | Year: 2011

Increased environmental awareness has promoted the need for improved feedlot runoff control. The use of vegetative treatment systems (VTSs) to control and treat feedlot runoff may enhance environmental security and protect water quality. Knowledge of effluent nutrient concentrations throughout the vegetative treatment system is required to evaluate system performance and impact on water quality. Previously collected VTS monitoring data has provided the opportunity to investigate relationships between effluent quality parameters. The objective of this study was to evaluate, through correlation and regression, the relationships between total solids, nutrients, and effluent quality indicator concentrations of feedlot runoff at various stages of treatment in a VTS, including solid settling basin, vegetative infiltration basin, and vegetative treatment area effluent. Results of a correlation and primary factor analysis showed that most of the effluent concentrations were strongly correlated to each other, with a single factor capable of describing more than 60% of the total variability of the monitored parameters. Regression equations were developed to relate nutrient content and effluent quality indicator concentrations to total solids concentrations. Results were satisfactory for NH 3-N, BOD 5, COD, Cl -, TP, and TKN, indicating that total solids concentrations provided significant insight into VTS performance relative to nutrient concentration and effluent quality indicators. A comparison between predicted, based on total solids content, and monitored annual mass release of the parameters was conducted. No statistical difference was found for NH 3-N, BOD 5, COD, Cl -, TP, and TKN; indicating that effluent volume release along with total solids concentrations could be used to provide an estimate of nutrient mass in solid settling basin, vegetative infiltration basin, and vegetative treatment area effluent. © 2011 American Society of Agricultural and Biological Engineers.


Andersen D.S.,Iowa State University | Burns R.T.,University of Tennessee at Knoxville | Helmers M.J.,Iowa State University | Moody L.B.,Fertilizer Institute
Transactions of the ASABE | Year: 2014

Increased environmental awareness has prompted the need for improved feedlot runoff control. Vegetative treatment systems (VTSs) provide a cost-effective option that may enhance environmental security by protecting water quality. Vegetative treatment systems are typically designed on the basis of hydraulic performance, which may result in excess application of some nutrients, specifically nitrogen and phosphorus. Groundwater quality monitoring is required to determine the effect, if any, that VTSs have on groundwater. Shallow groundwater (2 to 10 m) quality beneath six VTSs in Iowa was monitored over a four-year period. Monitoring wells were located upgradient, within, and downgradient of the VTSs. Groundwater samples were collected on a monthly basis and analyzed for ammoniacal nitrogen, chloride, nitrate-nitrogen, and fecal coliforms. A trend analysis was conducted to evaluate groundwater response patterns to VTS construction and use. In general, monitoring wells located within and downgradient of the VTS showed increasing trends in chloride and decreasing trends in nitrate concentrations. No trends for fecal coliforms or ammoniacal nitrogen were seen. Statistical analysis was performed to test for concentration differences between upgradient, within, and downgradient monitoring wells. In general, no differences in ammoniacal nitrogen concentration were seen. Fecal coliform concentrations were generally highest at the monitoring well within the VTS, but no difference was found between upgradient and downgradient concentrations. Chloride concentrations were generally significantly higher within and downgradient of the VTS when compared to the upgradient well; nitrate concentrations were generally significantly lower within and down-gradient of the VTA than upgradient. © 2014 American Society of Agricultural and Biological Engineers.


Andersen D.S.,Iowa State University | Burns R.T.,Iowa State University | Burns R.T.,University of Tennessee at Knoxville | Moody L.B.,Iowa State University | And 6 more authors.
Journal of Environmental Management | Year: 2013

Beef feedlots of all sizes are looking for more cost-effective solutions for managing feedlot runoff. Vegetative treatment systems are one potential option, but require performance evaluation for use on concentrated animal feeding operations. The performance of six vegetative treatment systems on open beef feedlots throughout Iowa was monitored from 2006 through 2009. These feedlots had interim, National Pollution Discharge Elimination System permits that allowed the use of vegetative treatment systems to control and treat runoff from the open feedlots. This manuscript focuses on making within site comparisons, i.e., from year-to-year and component-to-component within a site, to evaluate how management changes and system modifications altered performance. The effectiveness, in terms of effluent concentration reductions, of each system was evaluated; nutrient concentration reductions typically ranged from 60 to 99% during treatment in the vegetative components of the vegetative treatment systems. Monitoring results showed a consistent improvement in system performance during the four years of study. Much of this improvement can be attributed to improved management techniques and system modifications that addressed key performance issues. Specifically, active control of the solid settling basin outlet improved solids retention and allowed the producers to match effluent application rates to the infiltration rate of the vegetative treatment area, reducing the occurrence of effluent release. Additional improvements resulted from system maturation, increased operator experience, and the addition of earthen flow spreaders within the vegetative treatment area to slow flow and provide increased effluent storage within the treatment area, and switching to active management of settling basin effluent release. © 2013 Elsevier Ltd.


Pepple L.M.,Iowa State University | Andersen D.S.,Iowa State University | Burns R.T.,University of Tennessee at Knoxville | Moody L.B.,Fertilizer Institute
Transactions of the ASABE | Year: 2011

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. © 2011 American Society of Agricultural and Biological Engineers.


Rahman S.,North Dakota State University | Xin H.,Iowa State University | Xin H.,Egg Industry Center | Roberts S.A.,Akey Nutrition and Research Center | And 6 more authors.
Transactions of the ASABE | Year: 2012

Ammonia (NH3) emissions from laying hens are affected by nutrient content of the diet, manure quantity, and manure properties such as moisture content, nitrogen content, and pH. These production traits may vary with strain of the hen. However, limited information is available concerning the effects of laying-hen genetics on manure properties and NH3 emission. This study was conducted to comparatively quantify production performance, manure properties, and NH3 emissions (through N mass balance) of four white-egg-laying strains (Hy-Line W-36, Hy-Line W-98, Lohmann LSL Lite, and Bovans White) and four brown-egg-laying strains (Hy-Line Brown, Lohmann Brown, ISA Brown, and Bovans Brown) during two production periods of 27-28 weeks (P1) and 35-36 weeks (P2) of age. The diets were formulated to meet the nutritional needs of the brown and white hens. As a result, crude protein contents during P1 and P2 were, respectively, 13.2% and 15.2% for the brown hens but 14.5% and 17.4% for the white hens. The results showed that the brown and white hens had similar hen-day egg production (97.5% to 89.2% for brown hens and 96.0% to 88.2% for white hens) and egg mass output (57.1 to 52.6 g d-1 hen-1 for brown hens and 55.6 to 51.2 g d-1 hen-1 for white hens) but different feed consumption (112 to 98 g d-1 hen-1 for brown hens and 101 to 93 g d-1 hen-1 for white hens, p < 0.01) and feed efficiency (1.97 to 1.87 g feed g-1 egg for brown hens and 1.82 g feed g-1 egg for white hens, p < 0.0001 and p = 0.11). The higher feed consumption for the brown hens stemmed from their heavier body mass (1.81 to 1.78 kg vs. 1.56 to 1.53 kg for white hens). Manure moisture content was higher for the brown hens than for the white hens, although the dry-matter manure production was not significantly different. The results further revealed that under the experimental conditions (i.e., higher CP contents of the diet for the white hens than for the brown hens) the white hens had higher NH3 emissions than the brown hens as expressed per hen (37% to 19% higher, p = <0.001 to 0.016), per animal unit (AU, 500 kg live body mass; 59% to 39% higher, p = 0.0007 to 0.007), per unit of egg mass output (41% to 24% higher, p = 0.01 to 0.09), per unit of feed N consumed (39% to 27% higher, p = 0.01 to <0.0001), and per unit of dry manure (56% to 39% higher, p = 0.001 to 0.007). Certain differences existed in production performance among strains within the brown or white hens, but no differences in NH3 emissions were detected. Because of the relatively small sample size (number of hens involved) and the relatively short monitoring period, the results should be referenced with these limitations in mind. Further larger-scale studies with longer monitoring periods to verify these findings are warranted. © 2012 American Society of Agricultural and Biological Engineers.


Baker J.F.,Iowa State University | Andersen D.S.,Iowa State University | Burns R.T.,University of Tennessee at Knoxville | Moody L.B.,Fertilizer Institute
Transactions of the ASABE | Year: 2013

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. © 2013 American Society of Agricultural and Biological Engineers.

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