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2025 Webinars Approved for ARPAS Continuing Education Units

These webinars have been approved for 1 continuing education unit (each) as part of the American Registry of Professional Animal Scientists (ARPAS) program. To receive CEUs, view a live or archived webinar, complete an evaluation (if available), and contact ARPAS, 217-356-5390 to have the credit applied to your CEU balance. Repeat this process for each webinar being utilized for CEUs.

2025 Webinars

More Webinars…

2025 Webinars

Topics include: Drones, Remote Sensing, Nutrient Cycle, Mortality Management, 360Rain, Discharge Water Quality, Ammonia Deposition, NRCS-CIG Programs, Manure Application  More…

2024 Webinars

Topics include: AFO Air Emission Estimations, Soil Health, Mortalities, Air Quality, Models & Tools, Circularity, Precision Ag, Environmental Progress, Dairy Manure, Farm Safety, PFAS. More…

2023 Webinars

Topics include: Carbon Markets, Soil Health, Mortalities, Air Quality, Models & Tools, Vector Control, Antibiotic Stewardship, Manure Additives, Minimizing Risk, and Energy Conservation. More…

2022 Webinars

Topics include: Carbon Markets, Worker Safety, CEAP I & II, Antimicrobial Resistant movement, Manure Nutrient Trends, Vermifiltration, Urban Manure Management, Manure Pipelines, and Lagoon and Digester Cleanouts. More…

2021 Webinars

Topics include: Edge of Field Monitoring, PFAS, Food Safety, Digesters & Natural Gas, Manuresheds, Extreme Events, Antimicrobial Resistance, Sustainability, Weeds, and Soil Health. More…

2020 Webinars

Topics include: Less typical species, designer manure, precision technologies, human health, poultry systems, communicating science, compost emissions, PFAS, and manure transfers. More…

2019 Webinars

Topics include: Separation technologies, soil health, cleaning barn exhaust air, pathogens, antimicrobial resistance, greenhouse gas emissions, nutrient inventories, and phosphorus management. More…

2018 Webinars

Topics include: Emergency response, treatment technologies, manure foaming, small farm equipment, manure’s impact on soil, manure irrigation, manure pit death, sampling, and biosecurity. More…

2017 Webinars

Topics include: Climate resiliency, avian influenza, side-dressing nitrogen on emerged corn, runoff risk advisory tools, anaerobic digestion, manure handling safety, long-term manure application, and managing edge of field losses.. More…

2016 Webinars

Topics include: Construction and maintenance of manure ponds, antibiotic resistance, manure entomology, NAQSAT, Drones, manure safety and transport, the nutrient recycling challenge, Vermont nutrient management training course, and pathogens. More…

2015 Webinars

Topics include: Manure Apps, Gypsum Bedding, Livestock Housing, Tile Drained Lands, Micro Manure Management, Horse Manure Composting, Uses of Biochar, Thermal Manure-to-Energy Systems, Mortality Management during Avian Influenza, Communication Pathways, Communicating During Controversy. More…

2014 Webinars

Topics include: Capturing Nutrients, Manure as a biofuel, Water Quality Index, Liquid manure nutrients, Carbon credits, Bioaerosols, WOTUS, Biosecurity, Mortality composting, Whole Farm Nutrient management, Winter manure application, Next generation activities. More…

2013 Webinars

Topics include: Risk Management, Waste to Worth, Mono-slope beef barns and research results, Bioavailability of Phosphorus, Capturing Nutrients. More…

2012 Webinars

Topics include: Biofilters, The 4Rs, Microbes, Life-Cycle Assessments, Carbon Footprints, Nitrates, Adaptive Nutrient Managment, Chesapeake Bay, Emergency Management. More…

2011 Webinars

Topics include: Top-dressing manure, Chesapeake Bay, Soil Health, Reducing Odor Risk, Anaerobic Digestion, NMP implementation, NAEMS, Lagoon Closure, Manure Economics, 2011 NPDES CAFO rule. More…

2010 Webinars

Topics include: Cover Crops, Vegetative Environmental Buffers, Mortality Composting, Manure Spills, NAQSAT, Manure on No-Till, SPCC, Ammonia Emissions. More…

2009 Webinars

Topics include: Feeding Strategies, Carbon Footprint, Conserving Nitrogen, AFO Inspection, Mortalities, Air Emissions, Grazing Management. More…

2008 Webinars

Topics include: Market Based Conservation, Antibiotics and Hormones, Dry Manure Housing Systems, Ammonia, Small Farms, Regulations, Manure Management Planner Software. More…

2007 Webinars

Topics include: Integrated Nutrient Management, Manure Application to Legumes, Value of Manure in Land Application, Smithfield Project, Value Added Processing of Manure, Manure Treatment Technologies, Value of Manure in Energy Generation, Vegetative Treatment Systems, and Innovative Manure Treatment Technologies. More…

2006 Webinars

Topics include: CNMP Core Curriculum, Pathogens, EPA CAFO Regulations. More…

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Crops and Soil Resources Related to Swine Systems Project

Factsheets

Methodologies in Assessing Sustainability of Swine-Crop Systems

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Summary
This factsheet explains how Life Cycle Assessment (LCA) and soil evaluation tools are used to measure the full environmental impact of swine production—from feed crops to manure management. It shows how decisions about nutrients, soil health, and manure application can create both benefits and risks. Readers will gain practical insight into how whole-system tools support more efficient, sustainable pork production.

Authors
Priscila J. R. Cruz, Sailesh Menon, Caitlyn M. Phillips, and Charles W. Rice

Identifying Environmental Hotspots in Swine Production

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Summary
This factsheet identifies the key environmental hotspots in swine production, focusing on the stages that contribute most to emissions and resource impacts. It highlights feed production and manure management as major drivers of greenhouse gases, nutrient losses, and soil degradation. The summary also explains how soil type, cropping patterns, and regional differences influence environmental outcomes. By pinpointing where impacts are greatest, this resource helps producers target the practices that can most effectively improve sustainability.

Authors
Priscila J. R. Cruz, Sailesh Menon, Caitlyn M. Phillips, and Charles W. Rice

Sustainability Strategies for Swine-Crop Integration

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Summary
This factsheet highlights proven, practical strategies that improve sustainability in swine production without sacrificing productivity. It explores nutrient recycling, soil conservation practices, and precision technologies that reduce emissions while strengthening soil health. The resource also showcases manure treatment innovations and circular bioeconomy approaches that turn waste into renewable energy and valuable co-products. Readers will discover how integrated, science-based solutions can lower environmental impacts and build more resilient farming systems.

Authors
Priscila J. R. Cruz, Sailesh Menon, Caitlyn M. Phillips, and Charles W. Rice

 

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Nutrition Technology Resources Related to Swine Systems Project

Factsheets

Zinc, Copper, Potassium, Sulfur, and Iron Excretion in Pigs

Summary
Minerals like zinc, copper, iron, potassium and sulfur are essential for pig health. However, most of the excess is excrete in manure and urine which contributes to environmental issues. Researchers analyzed data from 51 studies to create models predicting mineral excretion based on dietary intake. These new excretion models are a powerful tool for producers looking to reduce environmental impact.

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Carbon: Ingredient Values for Formulation in Swine Diets

Summary
Keeping swine production sustainable is a key focus for experts currently. A new fact sheet explores how carbon content in pig feed, influenced by ingredients such as corn, soybean meal, and even bakery meal. These ingredients can drastically affect the environmental impact of pork. By using detailed chemical analysis and updated formulas, researchers are building a more accurate picture of pork’s carbon cost.

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Mineral Excretion and Environmental Impact of Typical U.S. Swine Diets

Summary
As consumer expectations around sustainability continue to rise, livestock producers are being challenged to look beyond just growth and profitability. This factsheet explores how modern swine diet formulation can influence environmental impact and mineral excretion, using Life Cycle Assessment to evaluate feeding strategies. By comparing typical U.S. swine diets, the analysis highlights opportunities to reduce greenhouse gas emissions and water use and identifies critical stages where mineral excretion can be better managed.

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Swine Diets in the U.S. Industry for LCA Footprint Analysis

Summary
Feed is vital to U.S. pork production, with more than 61 million tons used in 2024 alone. This factsheet breaks down where that feed comes from and how it is used across different stages of production. Using data from IFEEDER, it shows how core ingredients like corn and soybean meal dominate U.S. swine diets, while DDGS and added fats are incorporated to meet the changing nutritional and economic demands of sows, nursery pigs, and finishing pigs.

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Improving Feed and Nutrient Utilization by Optimizing Diet Energy and Nutrient Levels: Protein

Summary
As pork production grows, improving feed efficiency is essential to reducing environmental impact. This factsheet explains how lowering crude protein and supplementing with crystalline amino acids can significantly reduce nitrogen excretion without harming pig performance. It also outlines the importance of proper lysine to crude protein ratios to maintain productivity while improving nitrogen efficiency. Readers will gain practical, research-based strategies to support both environmental sustainability and production goals.

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Improving Feed and Nutrient Utilization by Optimizing Diet Energy and Nutrient Levels: Calcium & Phosphorus

Summary
As pork production increases worldwide, improving mineral nutrition is key to reducing environmental impact. This factsheet explains how excess dietary phosphorus contributes to manure losses and water quality concerns, and why balancing calcium and phosphorus is critical for both performance and sustainability. It highlights advances in digestible phosphorus estimates and the use of phytase to improve nutrient utilization and lower excretion. Readers will gain practical, research-based strategies to optimize mineral feeding while protecting environmental resources.

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Improving Nutrient Utilization Through Diet Formulation

Summary
As global pork production rises, improving feed efficiency and nutrient use is essential to reduce environmental impact. This factsheet explains how ingredient selection, feed additives, and liquid feeding influence nutrient digestibility, growth, and manure nutrient losses. Selecting ingredients with high nutrient retention, using enzymes and other additives, and adopting liquid feeding can lower nitrogen and phosphorus excretion while supporting performance. Readers will learn practical strategies to balance productivity, feed cost, and environmental sustainability in swine diets.

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Opportunities to Optimize Nutrient Intake by Feeding Management

Summary
Global pork demand is projected to rise sharply, making efficient feeding and management of pigs more critical than ever. Strategies like phase feeding, precision feeding, and split-sex diets can dramatically reduce nutrient waste while maintaining growth performance. Optimizing meal size, feeding frequency, and feeder design further improves nutrient utilization and lowers environmental impact. This factsheet reveals practical, research-backed approaches to producing more pork with less waste, saving both money and resources.

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Improving Feed and Nutrient Utilization by Optimizing Diet Energy and Nutrient Levels: Energy

Summary
Global pork demand is rising and most environmental impact comes from feed production and nutrient waste. Optimizing dietary energy and balancing lysine and other nutrients improves feed efficiency, growth, and sustainability. Precise diet formulation, feed processing, and proper animal management help convert more energy into lean growth rather than waste. This factsheet shows research-based strategies to maximize nutrient use and reduce environmental impact.

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Improving Feed and Nutrient Utilization by Feed Processing

Summary
Global pork demand is rising, and most environmental impact comes from feed production and nutrient waste. Feed processing methods like grinding, pelleting, extrusion, and enzyme treatments improve nutrient digestibility and feed efficiency, supporting growth while reducing waste. Optimal particle size, high-quality pellets, and careful combination of methods maximize benefits without harming pig health. This factsheet highlights research-based strategies to enhance feed efficiency, animal performance, and sustainability in pork production.

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Improving Feed and Nutrient Utilization by Optimizing Diet Energy and Nutrient Levels: Fiber

Summary
Global pork demand is rising, and most environmental impact comes from feed production and nutrient losses. Dietary fiber influences nutrient digestibility and nitrogen excretion, with fermentable fibers shifting nitrogen from urine to feces, slowing environmental release. This shift improves nitrogen retention in pigs while reducing ammonia emissions and nitrate leaching from manure. The factsheet highlights how strategic fiber use can boost sustainability in pork production without compromising animal performance.

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Improving Feed and Nutrient Utilization by Optimizing Diet Energy and Nutrient Levels: Microminerals

Summary
Global pork production is rising but over-supplementation of trace minerals like copper, zinc, manganese, and iron causes environmental contamination. Many diets provide 2 to 10 times the required levels, especially in nursery pigs, leading to excessive fecal excretion. Using organic minerals improves bioavailability, allowing lower inclusion while maintaining growth. These strategies can reduce mineral excretion by up to half.

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Non-Nutritional Factors that Influence Feed Efficiency and Nutrient Utilization

Summary
Global pork production is rising, and most environmental impacts come from feed, so improving pig health, management, and feed efficiency is essential. Genetics improve growth, lean tissue deposition, and nutrient efficiency, while environmental temperature affects intake and nutrient use, with cold increasing feed demand and heat reducing intake and growth. Disease lowers digestibility, growth, and feed efficiency, increasing nitrogen excretion and environmental impact. Porcine somatotrophin can shift nutrients toward protein deposition, improving growth and feed efficiency, but its use is limited by consumer concerns.

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Journal Publications

Technologies and Practices to Improve Feed and Nutrient Utilization by Pigs

Authors
Contributors: Ron Aldwin S Navales, Mike D Tokach, Joel M DeRouchey, Katelyn N Gaffield, Jason C Woodworth, Robert D Goodband, Jordan T Gebhardt, Russel M Euken, and Jack C M Dekkers

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Popular Press Articles

Gauging the carbon footprint of feeding pigs in the US

View Full Article on Pig Progress

Increasing knowledge of pigs, diets, and feeds could further improve nutrient utilization and reduce potential environmental effects

View Full Article on National Hog Farmer

Technologies and Practices to Improve Feed and Nutrient Utilization by Pigs: Diet Nutrient Levels and Feed Formulation

View Full Article on IFEEDER

Technologies and Practices to Improve Feed and Nutrient Utilization by Pigs: Feeding Strategies, Feeding Management, Feed Processing and Non-nutritional Factors

View Full Article on IFEEDER

Why better feed data matters for pork carbon footprints

View Full Article on All About Feed

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Bridging the Gap: Communicating Sustainability Research to Southern Idaho Dairy Farmers

Purpose

This is an example of an informative social media post that shows the ISAID Grant’s research with dairy manure.
This is an example of an informative social media post that shows the ISAID Grant’s research with dairy manure.

Dairy farming is at the heart of Southern Idaho’s economy and way of life. As pressures mount around environmental impact, consumer expectations, and long-term viability, sustainability has become essential to the future of dairy. While research in this area has made significant strides, many farmers struggle to access and apply this information in a way that makes sense for their operations. Scientific studies are often dense, packed with technical jargon, and filled with data that doesn’t always connect to the everyday realities of farming.

This graphic explains what circular bioeconomy is, a term used often in sustainability research.
This graphic explains what circular bioeconomy is, a term used often in sustainability research.

This project aims to close the information gap by using research from the Idaho Sustainable Agriculture Initiative for Dairy (ISAID) Grant to make sustainability science more accessible and actionable. Our goal is to translate research into tools and messages that help farmers adopt practical, sustainable practices that benefit their operations and the broader agricultural landscape.

What Did We Do?

To better understand the communication barriers farmers face, we conducted a literature review focusing on agricultural communication and knowledge transfer, particularly in dairy sustainability. Our review included studies on the communication preferences of dairy producers, social media engagement in agriculture, and the role of trusted advisors such as veterinarians and extension specialists in knowledge dissemination. Key findings from this review highlighted the importance of concise, visually engaging content and digital platforms like Facebook and YouTube for reaching dairy farmers. We also examined studies on farmers’ motivations and perceived barriers to adopting sustainable practices, which emphasized the need for messages that align with farmers’ economic and operational priorities.

This graphic gives farmers suggestions for how to make their land more sustainable.
This graphic gives farmers suggestions for how to make their land more sustainable.

Additionally, research on sustainable practice adoption highlights that behavioral change plays a critical role in whether farmers choose to implement new sustainability measures. Concepts from the social science of behavior change, such as the Diffusion of Innovation (DOI) theory and the Reasoned Action Approach (RAA), help explain how farmers evaluate new practices. Key factors include perceived relative advantage, compatibility with existing practices, complexity, trialability, observability, and riskiness. These insights suggest that effective communication strategies should focus not just on providing information but also on addressing these concerns to increase adoption likelihood. Studies also show that demographics, land tenure, and financial constraints play significant roles in whether a farmer adopts new practices, reinforcing the need for tailored communication that takes these contextual factors into account.

Hydrochar and Biochar are often mentioned in the ISAID Grant’s research. This graphic explains what each one is and how it is used.
Hydrochar and Biochar are often mentioned in the ISAID Grant’s research. This graphic explains what each one is and how it is used.

To implement these strategies, we built a website that serves as a hub for sustainability research, providing easy access to summaries, case studies, and media. Additionally, we launched The Clever Cow Podcast, where industry experts, researchers, and farmers discuss sustainability, innovation, and best practices. A structured social media strategy further expands our outreach, allowing us to engage farmers through Facebook, Instagram, and YouTube. Recognizing the role of selective exposure and confirmation bias in how farmers consume information, we have designed our content to align with existing beliefs while also introducing new sustainability concepts in an engaging and relatable manner. To ensure our approach remains farmer-focused, we will conduct focus groups and surveys this summer to gather direct feedback, refine our outreach efforts, and develop communication strategies that effectively bridge the gap between researchers and the dairy community.

What Have We Learned?

Initial research and discussions suggest that farmers value concise, visually engaging content over lengthy technical reports. Social media and digital platforms, especially Facebook and YouTube, have emerged as preferred tools for accessing sustainability information. Farmers have also emphasized the importance of seeing practical examples of sustainability in action, such as case studies of dairy producers who have successfully incorporated sustainable practices. Additionally, partnerships with trusted organizations like local extension offices strengthen credibility and ensure that information is regionally relevant.

This informational card was used to share information with dairy producers about biodegradable plastic made from dairy manure.
This informational card was used to share information with dairy producers about biodegradable plastic made from dairy manure.

Our research also highlights the need to consider cognitive biases in message design. Confirmation bias and selective exposure influence the way farmers engage with agricultural information, meaning that they are more likely to interact with content that aligns with their existing beliefs. By strategically framing sustainability messages in ways that resonate with their values—such as economic benefits, operational efficiency, and long-term resilience—we can increase engagement and encourage the adoption of sustainable practices. These findings highlight the importance of tailoring communication strategies to respect farmers’ time while making complex sustainability research easier to understand and apply.

Future Plans

In summer 2025, we will conduct two focus groups (12 farmers each) and distribute a statewide survey targeting over 100 Southern Idaho dairy producers. These efforts will gather direct input on preferred communication channels, trusted sources of information, and barriers to engaging with sustainability research. Using this feedback, we will refine and test outreach tools such as short-form videos, podcast episodes, social media graphics, and research-backed infographics. The insights gained will inform the development of a flexible, scalable communication model that can be customized for other agricultural communities across the U.S.

Authors

Presenting author

Savanah Nunes Carpenter, M.S. Graduate Student, Media and Communications Director, ISAID Grant, University of Idaho

Corresponding author

Dr. Mireille Chahine, Acting Head and Professor, Department of Animal Veterinary and Food Sciences, University of Idaho, mchahine@uidaho.edu

Additional Information

To learn more, visit the ISAID Grant website: www.uidahoisaid.com

Follow us on social media:

This video explains my research in four minutes: https://youtu.be/_3JWGDQgf0Y?si=Hpu233CQXFb1Dk8R

 

Acknowledgements

This research was funded by the USDA Sustainable Agricultural Systems Initiative through the Idaho Sustainable Agriculture Initiative for Dairy (ISAID) grant (Award No. 2020-69012-31871).

Special thanks to the ISAID Grant research team, the University of Idaho Extension, and the Southern Idaho dairy farmers who will participate in the upcoming focus groups and surveys.

 

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. 2025. Title of presentation. Waste to Worth. Boise, ID. April 7-11, 2025. URL of this page. Accessed on: today’s date.

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Marketability of biodegradable pots by coupling transaction data and survey-based consumer willingness to pay (WTP) estimates

Purpose

Plastic pollution remains a pervasive environmental challenge and identifying economically viable alternatives is imperative. While regulatory efforts primarily target plastic bags, recent research highlights consumer acceptance of biodegradable alternatives across various product categories, including plant pots. However, much of the existing literature relies on estimates for “willingness-to-pay” (WTP) of certain products—according to their attributes—by using survey-based data of potential spending, which may not reflect actual market purchase behavior. This study connects hypothetical WTP survey data with observed market transactions from consumer panel data with the goal of better assessing the market of biodegradable pots.

What Did We Do?

Our analysis focuses on plastic pot store purchases recorded in the NielsenIQ consumer (transaction) panel data from 2006 to 2009. To ensure compatibility with results from a recent study of survey-derived WTP estimates, we restricted the sample to households purchasing a single plastic pot per month. Price purchase data is inflation-adjusted to 2024 values using U.S. Bureau of Labor Statistics (BLS) consumer price index data, updating the purchasing power to that of corresponding survey-based data. Given the limited number of scanner-based purchases (113 observations), we employed bootstrapping—a statistical technique that generates additional observations by repeatedly sampling from the original dataset—to augment the dataset to 471 transactions in order to meet the number of survey data observations.

A new price variable (composite price variable) was constructed by taking random market prices and adding random WTP survey data observations. These new prices and their dynamics represent increases in monthly expenditure. We incorporated key product attributes in our model; see details in Table 1 to analyze their effect. Attributes include different periods of biodegradability duration, the type of plastic product targeted by policy or regulation (single use food containers, packaging products, grocery bags, or all single-use products), and the type of bioproduct used (animal waste, agricultural waste, or wood waste feedstock). We estimated a conditional logit model using Stata, which allowed us to compare how consumers valued different options having several product attributes or features—including timespan for biodegradability and type of biodegradable material—when making purchasing decisions.

Table 1: Attribute tableSource: Field, 2024
Table 1: Attribute table
Source: Field, 2024

For the survey implementation, respondents are presented with three options each containing a randomly generated combination of four attributes and can select one option from three given options. A sample shown in Figure 1.

Figure 1: Sample choice blockSource: Field, 2024
Figure 1: Sample choice block
Source: Field, 2024

What Have We Learned?

VARIABLES Parameter Estimates
Previous Price, Increase in Expenditure (X0) -0.014***
(0.0012)
New Price, Increase in Expenditure (X1) -0.013***
(0.0012)
Time to Fully Biodegrade in years (X2) -0.003***
(0.0007)		 -0.004***
(0.0007)
Policy targeting:
(i) Single Use Packaging Products (X3) 0.067
(0.0824)		 0.112
(0.0833)
(ii) Single Use Food Containers (X4) 0.027
(0.0782)		 0.132*
(0.0782)
(iii) All Single Use Products (X5) 0.199**
(0.0888)		 0.292***
(0.0842)
Product source:
(i) Animal Waste Feedstock (X6) -0.010
(0.0681)		 -0.034
(0.0714)
(ii) Wood Waste Feedstock (X7) 0.015
(0.0661)		 0.025
(0.0667)
Neither Option 1 or Option 2 Policy choice (X8) -1.302***
(0.1110)		 -1.604***
(0.1100)
Observations 8,478 (471) 8,478 (471)

Column 2 shows estimate of attribute effects from combining transaction and survey WTP data, while Column 3 shows prior survey-based estimates of attribute effects. X₁ represents the New Price Variable in our analysis, while X0 corresponds to the increase in monthly expenditure in survey data analysis. Robust standard errors in parentheses. Asterisks indicate: *** p<0.01, ** p<0.05, * p<0.1

Table 3: Willingness-to-Pay Results ($)
VARIABLES WTP (n = 471) WTP (n = 471)
Time to Fully Biodegrade (years) -0.23 -0.26
Policy targeting:
(i) Single Use Packaging Products 5.15 7.97
(ii) Single Use Food Containers 2.08 9.46
(iii) All Single Use Products 15.31 20.86
Product Source:
(i) Animal Waste Feedstock -0.77 -2.44
(ii) Wood Waste Feedstock 1.15 1.76

Column 2 shows WTP estimates from combining transaction and survey WTP data, while Column 3 shows prior survey-based WTP estimates. All WTP estimates are in USD ($). n represents the total number of observations. Figures in bold represent significance at 5%.

Future Plans

We will incorporate demographic variables into the econometric model to examine how WTP varies across different consumer groups. Producers of biodegradable pots should consider WTP estimates across attributes in their feasibility assessment. Notably, each additional year of biodegradability decreases WTP by $0.23 per month, suggesting a preference for faster decomposition. Meanwhile, consumers exhibit no significant difference in WTP based on whether the bioproduct source is agricultural feedstock, animal waste, or wood waste, indicating flexibility in material choice.

Authors

Presenting & Corresponding author

Sanket Parajuli, Applied Economics Graduate Research Assistant, Department of Agricultural Economics and Rural Sociology, University of Idaho, Para5126@vandals.uidaho.edu

Additional author

Hernan Tejeda, PhD., Associate Professor and Extension Specialist, Department of Agricultural Economics and Rural Sociology, University of Idaho

Additional Information

Field, C. T. (2024). Greenbacks and grazing gambles: Exploring plastic preferences and pasture predicaments in two acts (Master’s thesis, University of Idaho).

U.S. Bureau of Labor Statistics. (2025). Consumer price index data. U.S. Department of Labor. Retrieved February 1, 2025, from https://www.bls.gov/cpi/data.htm

Acknowledgements

We thank USDA NIFA Sustainable Agricultural Systems project IDA02004-CG (Award No. 2020-69012-31871) for supporting this research. We also acknowledge the Kilts Center for Marketing Data Center at the University of Chicago Booth School of Business for providing access to NielsenIQ datasets. The conclusions drawn from the NielsenIQ data are those of the researcher(s) and do not reflect the views of NielsenIQ. NielsenIQ is not responsible for, had no role in, and was not involved in analyzing and preparing the results reported herein.

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. 2025. Title of presentation. Waste to Worth. Boise, ID. April 7–11, 2025. URL of this page. Accessed on: today’s date.

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Modeling of Electrochemical Ammonia Removal from Anaerobically Digested Dairy Wastewater

Purpose

Ammonia (NH3) found in anaerobically digested dairy wastewater (ADDW) could pose a serious threat to the environment. Various methods, including ion exchange and reverse osmosis, have been employed to remove ammonia from ADDW. While these techniques can be effective, they have significant drawbacks, particularly the generation of highly concentrated wastewater as a byproduct. This concentrated effluent poses a considerable challenge for safe disposal, potentially leading to secondary environmental impacts if not managed appropriately. As a result, while these methods address ammonia removal, they often shift the burden to another critical area, necessitating the development of more sustainable and holistic wastewater treatment solutions. In recent years, an electrochemical approach has garnered significant attention as an innovative and efficient alternative for wastewater treatment. This method is gaining growing recognition for its effectiveness in degrading a broad spectrum of pollutants, including ammonia, with minimal chemical additives. Its versatility, coupled with the potential for on-site application and reduced secondary waste production, makes electrochemical treatment a compelling solution for addressing the challenges posed by traditional wastewater treatment technologies. Different active radicals (•OH, OH–) generated during electrochemical process are used to oxidize NH3 to nitrogen gas (N2) and increase the selectivity of N2 (Eq. 1-4). The selectivity of N₂ in ammonia decomposition measures how much of the nitrogen from NH₃ is converted into N₂ gas instead of forming other nitrogen-containing byproducts.

(1) 2NH3 + 6OH– → N2 + 6H2O + 6e–      

(2) NH3 + •OH → •NH2 +H2O

(3) NH2 + •NH2 → N2H4

(4) N2H4  →  N2 + 2H2

Not many studies have looked into how ammonia breaks down during electrochemical treatment or how to predict this process. One common problem is that ammonia undergoes oxidation beyond the desired or controlled extent, leading to the formation of undesirable products like nitrate (NO3–), nitrite (NO2–) etc.   Achieving high ammonia removal efficiency and selective conversion to non-reactive N₂ gas is critical for optimizing electrochemical treatment. The purpose of this research was to investigate the viability and kinetics of electrochemical treatment for improving dairy wastewater quality through ammonia removal at different current densities.

What Did We Do?

Anaerobically digested dairy wastewater was sourced from a commercial dairy facility in southern Idaho and was stored at 39.2°F prior to the experiment. The concentrations of ammonia, nitrate, and nitrite in the collected wastewater were measured using a Hach DR 5000 spectrophotometer.

In the electrochemical reactor, a niobium-based boron-doped diamond (BDD/Nb) electrode was used as the anode, while a graphite plate served as the cathode (Fig. 1). Both electrodes had a working surface area of 3.10 in2 (20 cm²), with the interelectrode gap kept constant at 0.39 inch (1 cm).

Figure 1. Experimental set-up.
Figure 1. Experimental set-up.

Different levels of electric current (20, 30, 40, and 50 mA/cm2) were applied to study their effect on how ammonia was efficiently removed. The breakdown process of ammonia was analyzed using a mathematical model called pseudo-first-order kinetics. Additionally, changes in ammonia, nitrate, and nitrite levels and production of N2 gas were recorded over a 120-minute treatment period. The connection between the reaction speed and the applied current was also examined.

What Have We Learned?

Figure 2 illustrates the effect of applied current density on the removal of ammonia during the electrochemical treatment of ADDW. The removal of ammonia increased substantially with higher applied current densities (from 20 to 50 mA/cm2), with removal efficiency of 80.12% to 98.26% during a 120-minute treatment time. The applied current density is a critical operating factor that influences the electrochemical reaction by regulating the generation of active radicals on the electrode surface. This trend can be attributed to the fact that higher current densities enhance the formation of active radicals, which in turn accelerates the ammonia oxidation rate.

Figure 3 shows that ammonia removal at various current densities followed the pseudo-first order kinetic model. The relationship between the reaction rate constant (min-1) and applied current density (mA/cm2) demonstrated an exponential function with a high correlation coefficient value (R2= 0.98) (Fig. 4). This supports the accuracy of the pseudo-first order kinetic model in describing ammonia removal from ADDW. From the concentration profile, it is clear that a substantial amount of nitrogen was released from the system into the gas phase, primarily as N2 gas. This nitrogen loss from the system was estimated based on the total nitrogen mass balance. Ultimately, the selectivity of nitrogen reached to 90%. It was noted that the concentration of NH3 declined over time during the electrochemical treatment, with only a small amount of NO3− and NO2− being produced. The final concentration of NO3− and NO2− were 140 mg/L and 0.87 mg/L respectively. It has been documented that NO2⁻ can undergo reactions with NH3 to form N2 or be oxidized by oxygen gas (O2) to produce NO3⁻. This likely explains why the final concentration of NO2⁻ was lower compared to that of NO3⁻.  All of these findings clearly demonstrate that the electrochemical treatment can effectively remove ammonia from ADDW and achieve high nitrogen selectivity.

Figure 2. Effects of applied current densities on ammonia removal efficiency.
Figure 2. Effects of applied current densities on ammonia removal efficiency.
Figure 3. Pseudo-first order kinetic model for ammonia removal at different current densities.
Figure 3. Pseudo-first order kinetic model for ammonia removal at different current densities.
Figure 4. Relation between reaction rate constant and applied current density.
Figure 4. Relation between reaction rate constant and applied current density.

 Future Plans

In the future, we will work on nitrogen and phosphorus recovery simultaneously from dairy liquid manure by applying electrochemical treatment approach.

Authors

Presenting author

Ashish Kumar Das, Ph.D. Student, Environmental Science Program, College of Natural Resources, University of Idaho

Corresponding author

Dr. Lide Chen, Professor, Department of Soil and Water Systems, Twin Falls Research and Extension Center, University of Idaho, lchen@uidaho.edu

Acknowledgements

This research was funded by the USDA Sustainable Agricultural Systems Initiative through the Idaho Sustainable Agriculture Initiative for Dairy (ISAID) grant (Award No. 2020-69012-31871).

 

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. 2025. Title of presentation. Waste to Worth. Boise, ID. April 7–11, 2025. URL of this page. Accessed on: today’s date. 

 

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