A Decision-Support Tool for The Design and Evaluation of Manure Management and Nutrient Reuse in Dairy and Swine Farm Facilities

Purpose

The decision-support tool (DST) being developed facilitates the selection of manure treatment technology based on farm needs and nutrient balance requirements. A life cycle assessment (LCA) approach is used to determine and allocate among sources the whole-farm greenhouse gas (GHG) emissions and environmental impact of different manure management systems (MMS) to facilitate decision-making. The purpose of the tool is to help users identify the suite of technologies that could be used, given the farm’s unique set of preferences and constraints. The tool asks for an initial set of farm details and these values are cross-checked with predefined conditions before starting the simulation. This tool helps in the rapid quantification and assessment of treatment technology feasibility, GHG emissions, environmental, and economic impacts during the manure management decision-making process (Fig. 1). The decision algorithm operates based on user input for weightage priorities of criteria and sub-criteria related to environmental, economic, and technical components.

Figure 1. Graphical abstract

What Did We Do?

The DST is a Microsoft Excel-based tool with precalculated mass balance for a selected number of MMS alternatives representing current and emerging treatment technologies and practices. The MMS considered for the tool includes various handling systems, aerobic and anaerobic treatment systems, solid-liquid separation techniques, chemical processing units, etc. Modules were developed based on mass and energy balances, equipment capital & operating costs, unit process, and technology performance, respectively. The tool utilizes data specific to the country/region/farm where feasible and default values to calculate the overall economic and environmental performance of different MMS, providing results unitized per animal/day or per year.

Then, an LCA approach is used to evaluate the potential environmental footprints of each MMS considered. A life cycle impact assessment (LCIA) is comprised of detailed quantification of inputs and outputs of material flows in a specific treatment and/or conversion process. At the output level, it also defines and quantifies the main product, co-products, and emissions. The major focus on the treatment methods is quantifying the raw materials (manure, wash-water, bedding, etc.) that are to be handled in each MMS, thereby characterizing the properties of effluents (nutrients, gas emissions, etc.). The results include carbon, energy, water, land, nitrogen, and phosphorus footprints along with the effluent nitrogen, phosphorous, and potassium concentrations.

What Have We Learned?

Systematic selection of appropriate technology can provide environmental and economic benefits. Manure management systems vary in their design, due to individual farm settings, geography, and end-use applications of manure. However, the benefits of technological advancements in MMS provide manure management efficiencies and co-production of valuable products such as recycled water, fiber, sand bedding, and nutrient-rich bio-solids, among others. The handling efficiencies and environmental benefits provided by manure treatment technologies come with additional costs, however, so the tradeoffs between environmental benefits and implementation costs also need evaluation.

Future Plans

The next steps are to finalize the dairy module. We are refining the tool’s user interface and demonstrating to stakeholders to gather information regarding key assumptions, outputs, and the functionality of the tool. Further, we also plan to complete the swine module.

Authors

Sudharsan Varma Vempalli, Research Associate, University of Arkansas

Corresponding author email address

svvempal@uark.edu

Additional authors

Sudharsan Varma Vempalli, Research Associate, University of Arkansas

Erin Scott, PhD Graduate Assistant, University of Arkansas

Jacob Allen Hickman, Project Staff, University of Arkansas

Timothy Canter, Extension Specialist, University of Missouri

Richard Stowell, Professor, University of Nebraska-Lincoln

Teng-Teeh Lim, Extension Professor, University of Missouri

Lauren Greenlee, Associate Professor, The Pennsylvania State University

Jennie Popp, Professor, University of Arkansas

Greg Thoma, Professor, University of Arkansas

Additional Information

Detailed economic impacts and tradeoffs expected with the implementation of certain MMS related to this tool is presented during the conference by Erin Scott et al., on the topic “Evaluating Costs and Benefits of Manure Management Systems for a Decision-Support Tool”.

Varma, V.S., Parajuli, R., Scott, E., Canter, T., Lim, T.T., Popp, J. and Thoma, G., 2021. Dairy and swine manure management–Challenges and perspectives for sustainable treatment technology. Science of The Total Environment, 778, p.146319. https://www.sciencedirect.com/science/article/pii/S0048969721013875

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.

Evaluation of Greenhouse Gas Emissions from Dairy Manure

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Purpose

Greenhouse gas (GHG) emissions from dairy manure can be affected by barns, bedding and manure collection, as well as processing and storage. To reduce life cycle environmental impacts of milk production, it is important to understand the mechanisms involved in production and emission of GHGs from dairy manure. In addition to the GHGs emitted from the manure surface, the production of these gases in manure at different depths is an important but poorly understood driver of emissions. Because it is often not practical to measure GHG production and emissions directly in the field, simulation of these processes, both experimentally and through modeling, is needed to help understand the GHG emission mechanisms.Because manure samples are heterogeneous and their composition varies based on the bedding materials and bedding rate as well as cleaning frequency, it is also necessary to consider the impacts of these different types of manure heterogeneity and their impact on emission processes. Another important element that can impact GHGs emissions from dairy manure is oxygen. GHG emission rates can be different based on manure storage status (aerobic, anaerobic, and mixed conditions) and storage time. Several other factors, such as manure bedding materials, bedding rate, applied stress, temperature and moisture content can also impact the microbial activities that produces these GHGs. Our goals are to enhance understanding of the relationships between these factors and GHG emissions from dairy manure, and to identify strategies by which substantial reductions in GHG can be realized in a practical way.

What did we do?

In a controlled laboratory environment we investigated three different dairy manures: sand stacked manure, sawdust bedded manure, and organic sawdust bedded manure. The first two manures were studied and measured in 2016, and the last one was collected and measured in February 2017. After sample collection, manures were mixed in a cement blender to be more homogeneous, and were then transported to buckets and jars for compaction and storage. Nine buckets were filled with manure in layers, and each layer was characterized for physical and biochemical properties. Three levels of stress (0 N/m2, 4196 N/m2, and 12589 N/m2) were applied above the manure to emulate the impact of overburden at various pile depths. Manure bulk density and permeability for each bucket were measured, and the average of each treatment was summarized to evaluate relationships with GHG emissions. Four gases (NH3, CH4, CO2, and N2O) were investigated. The manure moisture content and water holding capacity were measured adjusted to create aerobic, anaerobic, and mixed conditions for manure microorganisms. Three moisture contents were applied to 300 g manure samples, each three replicates. Each manure storage condition was simulated in 2L glass vessels for five durations (one day, two weeks, one month, two month, and three months). The relationship between storage time and GHG rates was assessed.

Picture of cement blenderPicture of buckets and manure compactionPicture of dairy manure storage after blending and compaction

What have we learned?

The results showed that there are good prospects that GHGs reductions can be realized in dairy manure management. In this work, manure that was characterized between each sample layer in the buckets showed similar results, which means the samples are pretty homogeneous. Bulk density and permeability decreased with increasing applied stress. GHG emissions and ammonia emissions showed correlation with the compaction density. Using different bedding materials did impact the GHGs rate.

Future Plans

The combination of prediction models (DNDC and IFSM) and real-word data will be discussed next.

Corresponding author, title, and affiliation

Fangle Chang, post-doctoral at Penn State University, State College PA

Corresponding author email

fuc120@psu.edu

Other authors

Micheal Hile, Eileen E. Fabian (Wheeler),

Additional information

Micheal Hile, mlh144@psu.edu

Eileen E. Fabian (Wheeler), Professor of Agricultural Engineering, Environmental Biophysics, Animal Welfare, and Agricultural Emissions, Integrated Research and Extension Programs, Penn State University, State College PA, fabian@psu.edu

Tom L. Richard, Professor of Agricultural and Biological Engineering, Director of Penn State Institutes for Energy and the Environment, Bioenergy and Bioresource Engineering, Penn State University, State College PA, tlr20@psu.edu

Acknowledgements

This material is based upon work that is supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, under award number 2013-68002-20525. Any opinions, findings, conclusions or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.

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.

Drying and Rewetting Effects on Gas Emissions from Dairy Manure in Semi-arid Regions

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Abstract

The major source of emissions in animal production sites is from animal waste (manure), which can be in solid, slurry, or liquid states, exhibiting varying physical properties. Once manure is excreted from an animal, processes of biological decomposition and formation of gaseous compounds continue, but diminish as the manure cools and dries. However, increases in gas emissions following rewetting, particularly from precipitation, have been observed in various agricultural lands. Our study investigates changes of gaseous emissions through manure drying and rewetting processes to identify the effects of climatic conditions and manure management on gaseous emissions. We carried out drying and rewetting processes of dairy manure in a greenhouse to maintain moderate wintertime temperatures (20 – 40 C) while monitoring gaseous emissions through these processes. Closed dynamic chambers (CDC) coupled with a multiplexed Fourier Transformed Infrared (FTIR) spectroscopy gas analyzer provided gas flux estimates. The analyzer was capable of monitoring 15 pre-programmed gases simultaneously including typical gaseous compounds and greenhouse gases emitted from manure sources; namely, ammonia, carbon dioxide, methane, nitrous oxide, oxides of nitrogen, and volatile organic compounds. Magnitude of dairy manure gas emissions resulting from variations in moisture and temperature provide insight toward enhancing manure management decisions. Results from our study should further understanding of manure gas emission temporal dynamics that are largely dictated by heat and by drying and rewetting processes that impact the generation and delivery of gasses to the atmosphere. Our overall goal is to advance development of appropriate best management practices to reduce gas emissions for dairy operations in semi-arid regions.

Purpose

The objective of this project is to identify the effects of climatic conditions and manure management on gaseous emissions. The results from our study will be used to advance development of appropriate best management practices to reduce gas emissions for dairy operations in semi-arid regions.

Fig 1. Gas emissions from two dairy manure samples were monitored in a greenhouse to compare the magnitude of gas fluxes through manure drying and rewetting processes.

What Did We Do?

We investigated changes in gaseous emissions by carrying out  drying and rewetting processes of dairy manure in a greenhouse to maintain moderate summertime temperatures (20 – 40 oC) while monitoring gaseous emissions. Closed dynamic chambers (CDC) coupled with a multiplexed Fourier Transformed Infrared (FTIR) spectroscopy gas analyzer provided gas flux estimates. The analyzer was capable of monitoring 15 pre-programmed gases simultaneously including typical gaseous compounds and greenhouse gases emitted from manure sources; namely, ammonia, carbon dioxide, methane, nitrous oxide, oxides of nitrogen, and volatile organic compounds. Gas emissions from two dairy manure samples were monitored to compare the magnitude of gas fluxes during 14 days of manure drying and rewetting processes.

Fig 2. Gas emissions were determined using the closed dynamic chambers integrated with a multiplexed Fourier Transformed Infrared (FTIR) spectroscopy gas analyzer.

What Have We Learned?

An increase in surface water content occurring after a rewetting event (e.g., simulated 5 mm of rain) represents an abrupt increase in manure moisture content, which can promote microbial activity and a commensurate increase in gas emissions from manure. In our study, we found gas fluxes were actually suppressed during and shortly after the rewetting process, mainly due to reduction in air-filled pore space causing reduced gas diffusivity in the manure crust layer. As the wet layer dried, gas emissions eventually increased to levels prior to wetting.

Future Plans

Future experiments include: (1) simulation of manure drying-rewetting with various amount of water and rewetting times,  (2) considering the immediate response time and effective period of the pulse response of the gas fluxes after rewetting which might have been missed in our study, (3) Further

Fig 3. Manure sample after the rewetting process.

investigation of the effect of the crust layer on water and gas transport from and into manure.

Authors

Pakorn Sutitarnnontr, Graduate Student, Dept. of Plants, Soils, and Climate, Utah State University, pakorn@aggiemail.usu.edu

Enzhu Hu, Dept. of Plants, Soils, and Climate, Utah State University

Rhonda Miller, School of Applied Sciences, Technology, and Education, Utah State University

Markus Tuller, Dept. of Soil, Water, and Environmental Science, University of Arizona

Scott B. Jones, Dept. of Plants, Soils, and Climate, Utah State University

Additional Information

Contact Information: Pakorn Sutitarnnontr, Environmental Soil Physics Laboratory, Dept. of Plants, Soils, and Climate, Utah State University. Email: pakorn@aggiemail.usu.edu

Acknowledgements

The authors gratefully acknowledge support from the USDA-NIFA under the AFRI Air Quality Program (Grant # 2010-85112-50524) and the Western Sustainable Agriculture Research and Education Program (Grant # GW13-006).

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. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.