Evaluating Costs and Benefits of Manure Management Systems for a Decision-Support Tool

Purpose

The purpose of the decision-support tool is to help livestock producers understand the costs of implementing new technology and the potential benefits associated with nutrient and water recovery, and how these compare across systems. Livestock agriculture is under increased scrutiny to better manage manure and mitigate negative impacts on the environment. At the same time, the nutrients and water present in manure management systems hold potential economic value as crop fertilizer and irrigation water. While technologies are available that allow for recovery and/or recycling of solids, nutrients and water, appropriate decision-support tools are needed to help farmers evaluate the practicality, costs, and benefits of implementing these systems on their unique farms.

What Did We Do?

In designing and refining the tool, we consider which economic components are important in driving the decision algorithm, as well as what is the most valuable economic output information for the user. We developed several “scenarios” defined by the unit processes used in the capture, treatment, storage, and usage of dairy manure. The costs and benefits related to each unit process were evaluated and aggregated for each scenario. Unit processes included flush/scrape activities, reception pit, sand recovery, solids separation, anaerobic digestion, composting, pond/lagoon storage, and tanker/drag hose land application.

Economic information was gathered from published literature, government documents, extension tools, and communication with academic, industry, and extension experts. We evaluated capital costs as an annual capital recovery value; operational costs including labor, energy, and repair and maintenance; cost savings resulting from sand/organic bedding and water reuse; fertilizer value of manure for use on-farm; revenue potential including the sale of treated manure nutrients and energy from anaerobic digestion; and the combined net costs or net benefits. Economic results are integrated into the multi-criteria decision algorithm. Results also elucidate economic tradeoffs across manure management systems (MMS), which can be used by farmers to assist in their decision-making.

What Have We Learned?

Economics is often about evaluating trade-offs between different choices or decisions. When evaluating results from the tool, we see that an increase in capital spending may lead to decreases in operational costs relative to capital costs, depending on farm size. This is due to a general reduction in labor and fuel costs associated with automated or additional manure treatment (e.g. increased spending on an MMS). For example, additional manure treatment can reduce land application expenses and increase cost savings from recovered sand or organic bedding. However, this larger capital outlay may or may not be possible based on the farm’s financial circumstances.

Future Plans

The next steps are to complete the economic analyses of a total of 60 MMS and integrate these into the decision-support tool. We plan to demonstrate this tool to extension specialists and producers to refine the user interface, key assumptions, functioning of the decision algorithm, and the usability of the results.

Authors

Erin E. Scott, PhD Graduate Assistant, University of Arkansas

Corresponding author email address

erins@uark.edu

Additional authors

Sudharsan Varma Vempalli, Postdoctoral Research Associate, University of Arkansas

Jacob Hickman, Program Coordinator, University of Arkansas

Jennie Popp, Professor, University of Arkansas

Richard Stowell, Professor, University of Nebraska-Lincoln

Teng Lim, Extension Professor, University of Missouri

Greg Thoma, Professor, University of Arkansas

Lauren Greenlee, Associate Professor, Penn State University

Additional Information

Related presentation during this session by Varma et al., titled “A Decision-Support Tool for The Design and Evaluation of Manure Management and Nutrient Reuse in Dairy and Swine Farm Facilities”.

Acknowledgements

We acknowledge funding support from the United States Department of Agriculture (USDA) National Institute of Food and Agriculture (NIFA) grant award (# 2018-68011-28691). We would also like to thank our full project team and outside experts for their guidance on this project.

 

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2022. Title of presentation. Waste to Worth. Oregon, OH. April 18-22, 2022. URL of this page. Accessed on: today’s date.

Advances in Nutrient Recovery Technology: Approaches to Controlling Recovered Product Chemistry

Purpose

Our recent work has focused on developing approaches to nutrient management and recovery, with a particular focus on using electrochemical and membrane technologies to control the chemistry of the recovered nutrient products. We are interested in being able to recover both ammonia and phosphate, and our goal is to create recycled fertilizer products that can allow the agricultural community to control the ratio of nitrogen to phosphorus in the recycled fertilizer products and to control whether those fertilizer products are in liquid form or in solid form. With the electrochemical technology focus, we see benefits that include no required chemical dosing, scalable reactor design, and the ability to couple to renewable energy sources. Our engineering research on nutrient recovery technology is conducted within a team that includes life cycle assessment, economic analysis, agronomic greenhouse and row crop studies, agricultural sector outreach, and the development of a decision-support tool to help farmers understand technology options for water and nutrient management.

What Did We Do?

We have investigated an electrochemical cell design that includes a magnesium metal anode and a stainless-steel cathode. The corrosion of the magnesium anode results in the release of magnesium cations into solution, and these magnesium cations promote the precipitation of struvite, otherwise known as magnesium ammonium phosphate hexahydrate (Figure 1). We have investigated how operating conditions of the electrochemical cell, including voltage, residence time, batch vs flow, and membrane separation of the two electrodes, affect nutrient recovery efficiency and the overall chemistry of the recovered precipitate. Our studies have included control experiments on synthetic wastewater compositions relevant to hog and dairy farm wastewaters, while we have also conducted laboratory-scale studies on natural wastewater samples from both agricultural and municipal sources. To demonstrate initial scale-up of an electrochemical reactor, we have designed a bench-scale reactor (Figure 2) that is capable of producing kilogram-level batches of struvite.

Figure 2. (a) Bench-scale batch reactor demonstration for kg-level struvite precipitation. (b) One engineering challenge is the precipitation of struvite on the electrode surface.

What Have We Learned?

The production of struvite from an electrochemical reactor can be controlled by the applied voltage and residence time of the wastewater in the reactor. Changes in reactor design, including the inclusion of a membrane to separate the anode and cathode and operation in batch vs flow mode, can change the composition of the struvite precipitate and can cause a change in the balance of struvite formed vs hydrogen gas formed from the electrochemical cell. We are also able to produce K-struvite, a potassium-based alternative to conventional struvite, that includes potassium rather than ammonium, and the production of K-struvite allows the recovery of the phosphate in a particulate fertilizer while also allowing the separation and recovery of ammonia in a separate liquid stream. We have learned that one of the primary challenges to the electrochemical reactor operation is fouling of the electrodes by the struvite precipitate (Figure 2), and we have developed a dynamic voltage control approach that enables minimal electrode fouling and therefore increases struvite recovery and decreases energy consumption. Our energy consumption values are similar to that of chemical precipitation processes that have been developed for nutrient recovery.

Future Plans

Future plans include further development and optimization of the dynamic voltage control approach to electrochemical reactor operation, which will allow us to control electrode fouling. We also plan to continue working with natural wastewater samples and further develop flow cell reactor design to understand how to translate our batch reactor studies to a flow reactor environment. Studies on K-struvite will focus on understanding the kinetics of K-struvite precipitation and the competing reactions (e.g., calcium precipitation and struvite precipitation) that might impact K-struvite recovery.

Authors

Lauren F. Greenlee, Associate Professor, Pennsylvania State University

Corresponding author email address

greenlee@psu.edu

Additional authors

Laszlo Kekedy-Nagy, Postdoctoral Fellow, Concordia University

Ruhi Sultana, Graduate Research Assistant, Pennsylvania State University

Amir Akbari, Graduate Research Assistant, Pennsylvania State University

Ivy Wu, Graduate Research Assistant, Colorado School of Mines

Andrew Herring, Professor, Colorado School of Mines

Additional Information

    1. Kekedy-Nagy, Z. Anari, M. Abolhassani, B.G. Pollet, L.F. Greenlee. Electrochemical Nutrient Removal from Natural Wastewater Sources and its Impact on Water Quality. Water Research (2022), 210, 118001, DOI: 10.1016/j.watres.2021.118001.
    2. Kékedy-Nagy, M. Abolhassani, R. Sultana, Z. Anari, K.R. Brye, B.G. Pollet, L. F. Greenlee. The Effect of Anode Degradation on Energy Demand and Production Efficiency of Electrochemically Precipitated Struvite, Journal of Applied Electrochemistry (2021), DOI: 0.1007/s10800-021-01637-y.
    3. Kékedy-Nagy, M. Abolhassani, S.I. Perez Bakovic, J.P. Moore II, B.G. Pollet, L.F. Greenlee. Electroless Production of Fertilizer (Struvite) and Hydrogen from Synthetic Agricultural Wastewaters, Journal of the American Chemical Society (2020), 142(44), 18844-18858. DOI: /10.1021/jacs.0c07916.
    4. Wu, A. Teymouri, R. Park, L.F. Greenlee, and A.M. Herring. Simultaneous Electrochemical Nutrient Recovery and Hydrogen Generation from Model Wastewater Using a Sacrificial Magnesium Anode, Journal of the Electrochemical Society (2019), 166(16), E576-E583. DOI: 10.1149/2.0561916jes.

Acknowledgements

The authors acknowledge funding from the USDA NIFA AFRI Water for Food Production Systems program, grant #2018-68011-28691 and funding from the National Science Foundation, grant #1739473.

 

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2022. Title of presentation. Waste to Worth. Oregon, OH. April 18-22, 2022. URL of this page. Accessed on: today’s date.

The MAnure PHosphorus EXtraction (MAPHEX) System for Removing Phosphorus, Odor, Microbes, and Alkalinity from Dairy and Swine Manures

Abstract

Animal manures contain nutrients [primarily nitrogen (N) and phosphorus (P)] and organic material that are beneficial to crops. Unfortunately, for economic and logistics reasons, liquid dairy and swine manure tends to be applied to soils near where it is generated. Over time, P concentrations in soils where dairy manure is applied builds up, often in excess of crop demands. We previously (Church et al., 2016, 2017) and have subsequently built, a full-scale version of a MAnure PHosphorus EXtraction (MAPHEX) System capable of removing greater than 90 percent of the P from manures. While originally designed to remove phosphorus, we have also shown that the MAPHEX System was also capable of removing odor and microbes, and of concentrating alkalinity into a solid, economically transported form. We have also lowered daily operating costs by testing the effect of lower-cost chemicals as alternatives to ferric sulfate, and by showing that the diatomaceous earth (DE) filtering material can be recycled and reused. We are currently building a system capable of treating over 100,000 gallons of Dairy Manure per day. This system is planned to be operational for demonstrating starting summer 2022.

Purpose

Swine and dairy manures are typically in slurry form and contain nutrients [primarily nitrogen (N) and phosphorus (P)] and organic material that are beneficial to crops. Unfortunately, the concentrations of nutrients in both manures are too low to make transportation of bulk manures over large distances economically viable. Furthermore, since it must be transported in tanks, that transportation is inconvenient as well. Therefore, these manures tend to be applied to soils near where they are generated, and, over time, P concentrations in soils increase to the point that soil P concentrations are often in excess of crop demands. Furthermore, because of the implication that P runoff from agricultural operations plays an important role in eutrophication of streams and other water bodies, farmers are experiencing increasing pressures and regulation to not apply animal manures to those soils.

We previously reported on an invention that 1) is designed to be a solution to the P overloading that happens when unnecessary P is added to agricultural soils, 2) is scalable such that it can be used as a mobile system, and 3) has shown to be capable of removing greater than 90 percent of the P from a wide range of dairy manures, while retaining greater than 90% of the N in the final effluent for beneficial use by the farmer.

What Did We Do?

We subsequently built a full-scale version of a MAnure PHosphorus EXtraction (MAPHEX) System capable of removing greater than 90 percent of the P from manures and have tested it on dairy manures. We also focused our efforts on lowering the daily operating costs of the system by developing a method to recover and reuse the diatomaceous earth used in the final filtration step, and testing alternative, lower cost chemicals that can be used in the chemical treatment step. We also performed pilot-scale tests on swine manures.

What Have We Learned?

The full-scale MAPHEX System removed greater than 90% of P from a wide variety of dairy manures, while leaving greater than 90% of the N in the final effluent to be used beneficially to fertigate crops. The System was also shown to recover and concentrate alkalinity into a solid form on a farm that used greater amounts of lime during manure handling, remove 50% of the odor from dairy manure and to remove greater than 80% of Total coliforms and E. Coli. Furthermore, the System has not shown to alter the pH of the final effluent respective to raw manures as other treatment technologies can. We have lowered daily operating costs by testing the effect of lower-cost chemicals as alternatives to ferric sulfate, and by showing that the diatomaceous earth (DE) filtering material can be recycled and reused.

In pilot-scale swine testing, we found that the MAPHEX System can remove greater than 96% of the phosphorus in swine manures. This essentially P free effluent can be beneficially used for fertigation without further loading the receiving soils with P. Scaling up the pilot-scale testing has the potential to reduce swine manure storage volumes to allow for mitigation of overflow problems during large storms. Furthermore, the pilot-scale study suggests that capital equipment costs and treatment costs for swine manure would be lower than for treating dairy manure.

Future Plans

We are currently building a simplified version of the MAPHEX System that will be capable of treating over 100,000 gallons of dairy manure per day. This system is planned to be operational for demonstrating starting summer 2022. We plan to use this simplified version for demonstration tests, and use the results obtained to model the effects of using MAPHEX technology compared to conventional manure handling practices on two paired watersheds. We also plan to demonstrate the full-scale system on a wide range of swine manures with on-farm testing.

Author

Clinton D. Church, Research Chemist, USDA-ARS University Park, PA

Corresponding author email address

Cdchurch.h2o@netzero.com

Additional Information

Church, C. D., Hristov, A. N., Bryant, R. B., Kleinman, P. J. A., & Fishel, S. K. (2016). A novel treatment system to remove phosphorus from liquid manure. Applied Engineering in Agriculture, 32: 103 – 112. doi:10.13031/aea.32.10999

Church, C. D., Hristov, A. N., Bryant, R. B., & Kleinman, P. J. A. (2017). Processes and treatment systems for treating high phosphorus containing fluids. US Patent 9,790.110B2.

Church, C. D., Hristov, A. N., Kleinman, P. J. A., Fishel, S. K., Reiner, M. R., & Bryant, R. B. (2018). Versatility of the MAPHEX System in removing phosphorus, odor, microbes, and alkalinity from dairy manures: A four-farm case study. Applied Engineering in Agriculture, 34: 567 – 572. doi:10.13031/aea12632

Church, C. D., Hristov, A., Bryant, R. B., & Kleinman, P. J. A. (2019). Methods for Rejuvenation and Recovery of Filtration Media. USDA Docket Number 129.17. U.S. Patent Application Serial No. 62/548,23

Church, C. D., S. K. Fishel, M. R. Reiner, P. J. A. Kleinman, A. N. Hristov, and R. B. Bryant. 2020. Pilot scale investigation of phosphorus removal from swine manure by the MAnure PHosphorus Extraction (MAPHEX) System. Applied Engineering in Agriculture 36(4): 525–531. doi: 10.13031/aea13698

https://www.ars.usda.gov/people-locations/person/?person-id=40912

https://tellus.ars.usda.gov/stories/articles/mining-manure-for-phosphorus/

https://agresearchmag.ars.usda.gov/2016/dec/phosphorus/

https://jofnm.com/article-112-Packaging-phosphorus-for-the-future.html

https://lpelc.org/versatility-of-the-manure-phosphorus-extraction-maphex-system-in-removing-phosphorus-odor-microbes-and-alkalinity-from-dairy-manures/

 

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2022. Title of presentation. Waste to Worth. Oregon, OH. April 18-22, 2022. URL of this page. Accessed on: today’s date.

Demonstrated Maximization of Nutrient Recovery from Swine Manure

Purpose

Previous evaluations of the technologies investigated were conducted in a batch mode of testing. This program was conducted to demonstrate the viability of the technologies investigated to significantly reduce phosphorus when operated in a continuous mode, pulling manure directly from a deep pit swine operation without agitating the pit. Additionally, this demonstration also explored the ability of several dewatering technologies to produce a stackable product containing the high phosphorus recovered in the form of amorphous calcium phosphate. Considerable data on this final product was collected from multiple off-site takers expressing interest in the final product. Figure 1 is a picture of the pilot setup.

Figure 1: Pilot Setup

What Did We Do?

Mobile test units were employed at a swine operation representative of a typical operation in Mercer County, OH. Manure was directly pulled from the deep pit at the host farm, and after initial dewatering, it was treated under conditions consistent with a detailed program conducted under sponsorship from Ohio Farm Bureau in summer 2019. Treated manure was then sent to multiple dewatering options including passive dewatering (geotextile bags) and mechanical separation. The demonstration program ran for six months and a total of 110,000 gallons of manure was treated continuously with multiple samples collected for analysis at third-party certified labs.

Twenty cubic yards of the initial manure solids were collected for use by a Cleveland off-site taker to investigate its viability as a composting foundational ingredient, while several different off-site takers were sent samples of the final dewatered material containing the recovered phosphorus. An additional three tons of stackable final product were sent to several off-site takers in Allen County, IN for use and evaluation, an additional 20 cubic yards of the geobag containing product were sent to a local farmer for application in a 40 acre wheat field and the remainder of the material (both manure solids and geobag material) were land applied by the host farm.

Figure 2 is a picture of the dewatered manure solids collected.

Figure 2: Dewatered manure solids

Figure 3 is a picture of the recovered phosphorus product.

Figure 3: Recovered phosphorus product

What Have We Learned?

We were able to confirm that the technologies demonstrated performed as expected when operating in a continuous mode. An average initial dewatered manure cake of 20.8% solids was obtained without the use of polymers and a consistent stackable product of 24.4% was obtained with the mechanical dewatering equipment used. An average of 96.1% recovery of total phosphorus was obtained during the pilot. This value compares to the average total phosphorus reduction of 95.5% measured at the batch mode operation in summer 2019. Limitations of the equipment used limited operation to approximately 7gpm but with properly sized pumps, this could be increased.

The operating cost of treatment averaged out to $0.0063/gallon (measured at $0.0064 in summer 2019). To dewater the product to stackable form varied depending on the equipment used, but costs of close to $0.01/gallon have been estimated. For the application demonstrated, the use of a geobag for final dewatering was not considered a viable option due to high costs (approximately $0.15/gallon treated) and the space required.

Future Plans

The Maumee Valley Authority was awarded an USDA Conservation Grant in partnership with Allen / Adams County of Indiana and Applied Environmental Solutions to further demonstrate continuous flow operation over an extended duration at a deep pit swine, dairy and mixed manure lagoon operation. A major focus of this effort will be in establishing the value and path to market for co-product streams produced. Additionally, efforts are underway to design and build a portable unit capable of treating 500,000 gpd of manure over a 3-5 day period. This would allow for treatment at smaller farms without the need for capital outlay by the individual farms. One purchaser of this design has already been identified for delivery in 2023.

In addition to the above, initial testing of a companion technology for the recovery of ammonia is also under investigation. Ammonia can be recovered in any number of ammonium salts (such as ammonium sulfate) and represents another opportunity to maximize the resource recovery from agricultural streams.

Authors

Presenting author

Rick Johnson, Director of Commercial Development, Applied Environmental Solutions

Corresponding author

Theresa Dirksen, Agriculture & Natural Resources Director, Mercer County (OH)

Corresponding author email address

theresa.dirksen@mercercountyohio.org

Acknowledgements

    • Ohio Water Development Authority
    • Mercer County Board of Commissioners
    • Ivo & Linda Post, Host Farm

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2022. Title of presentation. Waste to Worth. Oregon, OH. April 18-22, 2022. URL of this page. Accessed on: today’s date.

Electrochemical K-struvite formation for simultaneous phosphorus and potassium recovery from hog and dairy manures

Purpose

Intensive animal husbandry produces large  volumes of liquid manure with significant amounts of phosphorus, ammonium, and potassium as they pass through the feed of farm animals. As a result, direct land application of manure, the current common approach, causes environmental concerns such as soil over-fertilization and groundwater and surface water contamination, which leads to eutrophication. Manure nutrient management is, therefore, necessary to address these problems. While most engineering options are focused on phosphorus and ammonium recovery, few studies have pursued recovery methods for potassium. In this talk, we present an electrochemical technology using a sacrificial magnesium anode and a stainless-steel cathode for simultaneous recovery of phosphorus and potassium in the form of potassium-magnesium-phosphate (KMgPO4·xH2O, K-struvite).

Mg2+ + K+ + HnPO4n-3 + 6H2O = KMgPO4*6H2O + nH+

K-struvite has the potential to be used as a slow-release fertilizer and this technology will add flexibility to the  manure management strategies currently available by diversifying the recoverable by-products.

What Did We Do?

Figure 1. Calculated saturation index values as a function of pH. The water matrix contains 3000 mg/L potassium, 1000 mg/L phosphate, and magnesium with Mg:P ratio of 1.4.

To predict the thermodynamic stability of K-struvite, a thermodynamic model was developed based on the average ion concentrations of phosphorus, and potassium measured in real liquid pig manure (Figure 1). According to this model, magnesium phosphate is a possible by-product of K-struvite precipitation. Also, the probable formation of magnesium hydroxide was enhanced with increasing pH value due to the increase in hydroxide ion concentration. As a result, the ideal range for precipitation of K-struvite lies at pH values between 10 and 11.

To understand the role of pH on K-struvite formation, a 50 mM KH2PO4 solution was used to perform the preliminary batch electrochemical experiments. A constant voltage of -0.8 V vs. the Ag/AgCl reference electrode was applied to the pure magnesium anode using a potentiostat. One experiment was performed on the natural pH of the initial solution, 4.5, while potassium hydroxide was used to raise the initial pH of the second experiment to 9.5.

What Have We Learned?

Figure 2. The EDS results obtained of the recovered precipitates (a) pH=4.5, (b) pH=9.5 in 50 mM KH2PO4.

Energy-dispersive x-ray spectroscopy (EDS) of the recovered precipitates (Figure 2) indicate that by raising the initial pH from 4.5 to 9.5 the amount of potassium is increased in the precipitates. Also, due to the equimolar ratios of K:Mg:P at pH=9.5, the produced precipitates are likely K-struvite, while the pH= 4.5 sample likely contains some amount of magnesium phosphate.

This process also eliminates the disadvantages of the commonly used chemical precipitation methods, including magnesium salt dosing, and adding base to the system for pH control, due to in situ magnesium corrosion and hydroxide production at the magnesium anode surface. These advantages could potentially reduce the operating cost of the system and eliminate the addition of unnecessary salinity to wastewater through magnesium salt dosing.

Future Plans

Further investigation by using multiple characterization techniques (e.g., x-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR)) is necessary to identify the exact nature of precipitates. The initial experiments will be repeated at additional pH values to further understand the role of pH on the precipitation of K-struvite in the simplified synthetic wastewater and to further detail the characterization of the composition and morphology of K-struvite precipitates. These experiments are valuable , particularly because there are few literature reports that detail the physical and chemical structure of K-struvite.

Authors

Presenting author

Amir Akbari, Ph.D. Candidate, Department of Chemical and Biomedical Engineering, Pennsylvania State University

Corresponding author

Lauren F. Greenlee, Associate Professor, Department of Chemical and Biomedical Engineering, Pennsylvania State University

Corresponding author email address

greenlee@psu.edu

 

Additional Information

Once completed, future publications and data repository information will be available at https://sites.psu.edu/greenlee/

Acknowledgements

The authors would like to thank the U.S. Department of Agriculture, NIFA AFRI Water for Food Production Systems (#2018-68011-28691) for providing the funding support of this research through the “Water and Nutrient Recycling: A Decision Tool and Synergistic Innovative Technology” project.

 

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2022. Title of presentation. Waste to Worth. Oregon, OH. April 18-22, 2022. URL of this page. Accessed on: today’s date.

Recovery of Proteins and Phosphorus from Manure

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*Purpose

The recovery of phosphorus and proteins from manure could be advantageous to both offset costs and to improve and lessen the environmental impacts of manure storage and treatment. Phosphorous in manure can contaminate rivers, lakes, and bays through runoff, if applied onto cropland at excessive rates. Thus, recovering phosphorous from manure can not only help reduce phosphorus loss in runoff, but also reduces the use of commercial fertilizer based upon phosphate rock. Phosphorus mines have limited reserves and viable alternatives for replacing rock phosphate as fertilizer do not exist. Protein is a natural resource used in a wide range of commercial applications from pharmaceuticals to dietary supplements, foods, feeds, and industrial applications.

What Did We Do?

A new method for simultaneous extraction of proteins and phosphorus from biological materials has been developed and is presented.  The experiments used swine manure solids fraction after solids-liquid separation.  From raw manure, wet solids are dissolved in acidic solution and then treated with a basic solution so phosphorus will precipitate and be reclaimed.  The proteins in the washed solids can be extracted and concentrated with ultrafiltration and flocculation.

Test tubes filled with proteins from manure

What Have We Learned?

On a dry-weight basis, it was found that the separated manure solids contained 15.2-17.4% proteins and 3.0% phosphorus.  Quantitative extraction of phosphorus and proteins from manures was possible with this new system. The phosphorus was first separated from the solids in a soluble extract, then the proteins were separated from the solids and solubilized with an alkali solvent.  Both phosphorus and protein recovery were enhanced about 19 and 22%, respectively, with the inclusion of a rinse after the washing. The recovered phosphorus solids had 20.4% phosphates (P2O5).  The protein extract was concentrated using ultrafiltration (UF) and lyophilization to obtain a protein solids concentrate.  UF of 5 and 10 kDa captured all the proteins, but 30 kDa resulted in 22% loss.  The protein solids were converted into amino-acids using acid hydrolysis.  Further, the system was proved effective in extracting phosphorus and proteins from other biological materials, such as algae or crops. The recovered proteins could be used for production of amino acids and the recovered phosphorus could be used as a recycled material that replaces commercial phosphate fertilizers.  This could be a potential new revenue stream from wastes.

Future Plans

Further research will be conducted to reduce process costs and separate the amino acids.

Corresponding author (name, title, affiliation)

Matias Vanotti, USDA-ARS

Corresponding author email address

matias.vanotti@ars.usda.gov

Other Authors

A.A. Szogi, P.W. Brigman

Additional Information

Vanotti, M.B. and Szogi, A.A.  (2016).  Extraction of amino acids and phosphorus from biological materials. US Patent Application SN 15/350,283. U.S. Patent & Trademark Office.

USDA-ARS Office of Technology Transfer, Invention Docket No: 080.15, Contact: thomas.valco@ars.usda.gov

Acknowledgements

This research is part of USDA-ARS Project 6082-12630-001-00D “Improvement of Soil Management Practices and Manure Treatment/Handling Systems of the Southern Coastal Plains.”  We acknowledge the field and laboratory assistance of William Brigman and Chris Brown, USDA-ARS, Florence, SC.  Support by The Kaiteki Institute, Mitsubishi Chemical Holdings Group through ARS Cooperative Agreement 58-6082-5-006-F is acknowledged.

Spotlight on Manure Management in North Carolina and the Atlantic Coastal Plains


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Purpose 

To provide information about commonly-found manure management systems and approaches in North Carolina and the Coastal Plains, and discuss opportunities for technological innovation in the areas of manure management and nutrient recovery/utilization. Hear from a diverse panel of researchers, animal agriculture producers, and agency representatives who will provide background on the environmental conditions of the region and discuss specific technical considerations for innovative research and development. Learn about what has and hasn’t worked in past attempts to recover nutrients at animal agriculture farms in the area, and about the exciting possibilities for innovation in the U.S. Environmental Protection Agency’s (EPA’s) Nutrient Recycling Challenge (www.nutrientrecyclingchallenge.org).

What did we do? 

N/A

What have we learned? 

N/A

Future Plans 

N/A

Corresponding author, title, and affiliation 

Joseph Ziobro, Physical Scientist, U.S. Environmental Protection Agency; Hema Subramanian, Environmental Protection Specialist, U.S. Environmental Protection Agency

Corresponding author email 

ziobro.joseph@epa.gov; subramanian.hema@epa.gov

Other authors

Dr. John Classen, Associate Professor and Director of Graduate Programs, College of Biological and Agricultural Engineering at North Carolina State University

Dr. Kelly Zering, Professor of Agricultural and Resource Economics, North Carolina State University

Additional information

Session Agenda

  1. Background, history, and technical information about manure management in North Carolina and the Coastal Plains

Presenter: Dr. John Classen, Associate Professor and Director of Graduate Programs, College of Biological and Agricultural Engineering at North Carolina State University

  1. Lessons Learned from the Smithfield Agreement

Presenter: Dr. Kelly Zering, Professor of Agricultural and Resource Economics, North Carolina State University

  1. Panel: Challenges and Opportunities around Manure Management Systems

Moderator: Hema Subramanian

Panel to include the above speakers plus representatives from the local animal agriculture industry, North Carolina Department of Agriculture and Consumer Services, North Carolina Department of Environmental Quality, and U.S. Environmental Protection Agency. 

EPA’s Nutrient Recycling Challenge


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Purpose 

Come to this session to learn about the Nutrient Recycling Challenge and meet some of the involved partners and experts, as well as some innovators who are competing to develop nutrient recovery technologies that meet the needs of pork and dairy farmers. This session will begin with an overview of the challenge. Next, innovators will provide snapshot presentations about the technology ideas they are working on, followed by live feedback/Q&A sessions on each technology where we can harness the buzzing brainpower at Waste to Worth. Finally, we will move into a “workshop” designed to support innovators participating in the Nutrient Recycling Challenge as they refine their designs before they build prototypes.

What did we do?

Background on the Nutrient Recycling Challenge

At Waste to Worth 2015, the U.S. Environmental Protection Agency (EPA) hosted a brainstorm session about developing technologies that livestock farmers want to help manage manure nutrients. That session sowed the seeds for the Nutrient Recycling Challenge—a global competition to find affordable and effective nutrient recovery technologies that create valuable products farmers can use, transport, or sell to where nutrients are in demand. Pork and dairy producers, USDA, and environmental and scientific experts saw the tremendous opportunity to generate environmental and economic benefits, and partnered with EPA to launch the challenge in November 2015 (www.nutrientrecyclingchallenge.org).

What have we learned? 

There is a tremendous opportunity to generate environmental and economic benefits from manure by-products, but further innovation is needed to develop more effective and affordable technologies that can extract nutrients and create products that farmers can use, transport, or sell more easily to where nutrients are in demand.

In the Nutrient Recycling Challenge, innovators have proposed a range of technology systems to recover nitrogen and phosphorus from dairy and swine manure, including physical, chemical, biological, and thermal treatment systems. Some such systems may also be compatible with manure-to-energy technologies, such as anaerobic digesters. Farms of all sizes are interested in nutrient recovery, and there is demand for diverse types of technologies due to a diversity in end users. To improve the adoptability of nutrient recovery systems, it is critical that innovators are mindful of the affordability of technologies, and work to lower capital and operations and maintenance costs, and improve the potential for returns on investment. A key factor for offsetting the costs of a technology and improving its marketability will be in its ability to generate valuable nutrient-containing products that are competitive in the market.

Future Plans 

The challenge has four phases, in which innovators are turning concepts into designs, and eventually to pilot these working technologies on livestock farms. Thirty-four innovator teams whose concepts were selected from Phase I are refining technology designs in Phase II.  Design prototypes will be built in Phase III. This workshop is designed to help innovators maximize their potential for developing nutrient recovery technologies that meet farmer needs.

Corresponding author, title, and affiliation 

Joseph Ziobro, Physical Scientist, U.S. Environmental Protection Agency; Hema Subramanian, Environmental Protection Specialist, U.S. Environmental Protection Agency

Corresponding author email 

ziobro.joseph@epa.gov; subramanian.hema@epa.gov

Session Agenda

  1. Overview of the Nutrient Recycling Challenge, Hema Subramanian and Joseph Ziobro of EPA
  2. Nutrient Recycling Challenge Partner Introductions, Nutrient Recycling Challenge Partners (including National Milk Producers Federation, Newtrient, Smithfield Foods, U.S. Department of Agriculture Agricultural Research Service and Natural Resources Conservation Service, U.S. Department of Energy, and Water Environment & Reuse Foundation)
  3. Showcase of Innovators’ Technology Ideas
    • Decanter Centrifuge and Struvite Recovery for Manure Nutrient Management, Hiroko Yoshida
    • Manure Solids Separation BioFertilizer Produccion Drinking Water Efluente, Aicardo Roa Espinosa
    • Nutrient Recovery from Anaerobic Digestates, Rakesh Govind
    • Organic Waste Digestion and Nutrient Recycling, Steven Dvorak
    • Manure Treatment with the Black Solder Fly, Simon Gregg
  4. Nutrient Recycling Challenge Workshop for Innovators
    • Developing technologies: From concept to pilot (to full-scale), Matias Vanotti
    • Waste Systems Overview for Dairy and Swine and Innovative Technologies: What Steps Should be Taken (Lessons Learned), Jeff Porter

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2017. Title of presentation. Waste to Worth: Spreading Science and Solutions. Cary, NC. April 18-21, 2017. URL of this page. Accessed on: today’s date.

Recovery of Ammonia and Production of High-Grade Phosphates from Digester Effluents


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Purpose

Conservation and recovery of nitrogen and phosphorus from animal wastes and municipal effluents are important because of economic and environmental reasons. This paper presents a novel technology for separation and recovery of ammonia and phosphorus from liquid swine manure, which has significant amount of nutrients but also contains relatively high moisture content.

What Did We Do?

Phosphorus recovery via magnesium (MgCl2) precipitation was enhanced by combining it with ammonia recovery through gas-permeable membranes and low-rate aeration. Detailed procedures used in the research are provided in Vanotti et al. (2017).

Graphic of gas-permeable membrane

What Have We Learned?

The combination of low-rate aeration and gas-permeable membrane N recovery destroyed the natural carbonate alkalinity in the wastewater and increased pH values, which accelerated ammonia uptake in the gas-permeable membrane system and improved the phosphate recovery.  The process provided 100% phosphorus recovery efficiencies.   Surprisingly, the magnesium phosphates produced contained very-high phosphate grade (46% P2O5 ) similar to commercial superphosphate fertilizer and consistent with the composition of a rare biomineral called newberyite  that is found in guano deposits.   This is an important finding because we were able to produce from wastes a valuable phosphate product with high P2O5 content favored by the fertilizer industry.

Future Plans

Research will be summarized showing consistent results obtained with municipal side-stream effluents.  Economic considerations are provided in Dube et at. (2016).

Corresponding author (name, title, affiliation) 

Matias Vanotti, USDA-ARS

Corresponding author email address  

matias.vanotti@ars.usda.gov

Other Authors 

M.B. Vanotti, P.J. Dube, A.A. Szogi, M.C. Garcia-Gonzalez

Additional Information

Dube, P. J., Vanotti, M. B., Szogi, A. A., and García-González, M. C. (2016): Enhancing recovery of ammonia from swine manure anaerobic digester effluent using gas-permeable membrane technology. Waste Management 49:372–377.

Vanotti, M.B., Szogi, A.A., and Dube, P.J.  (2016): Systems and methods for recovering ammonium and phosphorus from liquid effluents. U.S. Patent Application 15/170,129. U.S. Patent and Trademark Office.

Vanotti, M.B., Dube, P.J., Szogi, A.A., M.C. Garcia-Gonzalez (2017): Recovery of ammonia and phosphate minerals from swine wastewater using gas-permeable membranes. Water Research 112:137-146

Acknowledgements

This article is part of USDA-ARS Project 6082-12630-001-00D “Improvement of Soil Management Practices and Manure Treatment/Handling Systems of the Southern Coastal Plains.”  We acknowledge the field and laboratory assistance of William Brigman and Chris Brown, USDA-ARS, Florence, SC, and the field sampling assistance of Diana Rashash, North Carolina Extension Service/ North Carolina State University.

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2017. Title of presentation. Waste to Worth: Spreading Science and Solutions. Cary, NC. April 18-21, 2017. URL of this page. Accessed on: today’s date.

Phosphorus Recovery from Anaerobic Swine Lagoon Sludge Using the Quick Wash Process

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Purpose

Long term and significant accumulation of sludge in anaerobic swine lagoons reduces its storage volume and ability to treat waste. Usually, excess accumulation of lagoon sludge is removed using pump or dredge. The dredged sludge is then land applied at agronomic rates according to its nutrient content.

The accumulation of phosphorus (P) in the sludge requires the largest area of land application based on crop agronomic requirements. Therefore, nutrient management plans may limit application to crop or pastureland near the animal facility to avoid P build up in excess of soil and crop assimilative capacities. Although dewatered sludge can be moved off the farm, transportation becomes less economical with increasing distances. An option is to extract and recover P in a concentrated form for its economical transfer to P-deficient croplands, for use as fertilizer.

What did we do?

A patented treatment process, called Quick Wash (QW), developed by USDA-ARS for extraction and recovery of P from animal manure solids was tested for recovery of P from anaerobic swine lagoon sludge. With the QW process,Chart of Quick Wash Process P was extracted in solution from dredged sludge by mixing with sulfuric acid prior to dewatering using polymer enhanced mechanical solid-liquid separation. After that, P was recovered by addition of liquid lime and an anionic flocculent to the separated liquid extract to form a calcium-containing P precipitate. The QW process generated two solid products: 1) sludge solids low in P; and 2) a concentrated P material.

What have we learned?

Picture of recovered phophorus material from lagoon sludge

While most of the nitrogen and carbon was left in the washed sludge solids, the QW process extracted and recovered as much as 90 % of the P from sludge. From results of a pilot field test, the P grade of the recovered phosphate was in the range of 24.0% – 30.5 % P2O5. The inclusion of this process in a lagoon sludge management plan offers producers an opportunity to locally land-apply the low-P sludge as a carbon-rich soil amendment and recover P as a valuable product for export from the farm.

Future Plans

USDA granted an exclusive license of the invention to Renewable Nutrients, LLC (Pinehurst, NC) to commercialize in the U.S the process for P recovery from animal and municipal waste streams. Renewable Nutrients is developping commercialization plans for the Quick Wash process that will include the operating and equipment costs of phosphorus recovery from dredged lagoon sludge.

Corresponding author, title, and affiliation

Ariel A. Szogi, Research Leader, USDA-ARS Coastal Plains Soil, Water, and Plant Research Center, Florence, SC.

Corresponding author email

ariel.szogi@ars.usda.gov

Other authors

Matias B. Vanotti; and Paul D. Shumaker – USDA-ARS Coastal Plains Soil, Water, and Plant Research Center, Florence, SC.

Additional information

https://www.renewablenutrients.com/

Acknowledgements

This work is part of USDA-ARS National Program 212; ARS Project 6082-12630-001-00D “Improvement of Soil Management Practices and Manure Treatment/Handling Systems of the Southern Coastal Plain.”