Purpose
Advanced manure processing technologies offer the potential to enhance the sustainability of these systems by separating manure into various streams for more efficient post-processing management. This presentation will synthesize findings from multiple full-scale studies on manure processing systems, focusing on separation technologies. It will also include recent evaluations of systems designed to treat manure to a quality suitable for discharge into surface waters. The data presented will cover separation efficiencies of key components, system performance, operational challenges, barriers to adoption, and the results of life cycle assessments of the environmental impacts when integrated into dairy facilities. These insights can provide valuable guidance for producers and stakeholders on how to integrate these systems effectively to achieve targeted environmental and operational outcomes.
What Did We Do?
A number of full-scale manure separation systems were analyzed over time to assess the nutrient separation efficiency of each component. This included systems from previously published data as well as two new sites analyzed in 2024-2025.
Site 1. A total of 45 manure samples were collected over 37 weeks from the Aqua Innovations treatment system located in Middleton, WI. Samples were collected from the (1) influent manure (following digestion), the (2) separated solid (screw press)and (3) liquids from the separator (screw press), (4) separated solid (centrifuge), (5) liquids from separator (centrifuge), (6) ultrafiltration (UF) concentrate and, (7) UF treated liquid, and the (8) reverse osmosis concentrate, and (9) clean water discharged.
Site 2. Samples were also collected from a dairy with a Livestock Water Recycling system located in Kiel, WI. Similarly, samples were collected over 45 sampling events from (1) liquid influent entering the inclined screen/roller press (raw manure), (2) liquid effluent following the inclined screen/roller press, (3) solids following the polymer assisted inclined screen/roller press, (4) liquid effluent following polymer assisted inclined screen/roller press, (5) outflow from clarifier, (6) liquid effluent following reverse osmosis (“clean” water), and (7) nutrient concentrate following reverse osmosis.
Samples were collected and shipped to Great Lakes Labs after each week of sampling and manure analyzed for manure total solids (or dry matter), total phosphorus, total nitrogen, ammoniacal nitrogen, potassium among many other sample parameters. Nutrient separation efficiencies were then compared for the entire system and each system component to previously collected data and data reported in literature.
What Have We Learned?
Separation efficiencies vary significantly for each nutrient through the system. Mutiple separation systems in series reduce variability in separation efficiency. Manure nitrogen is primarily removed from advanced treatment components, ultrafiltration and reverse osmosis, while solids and phosphorus are primarily removed in the initial separation stages.
Future Plans
Data will be further analyzed and published in a peer-reviewed journal. The data will also be integrated into a partial life cycle assessment to determine the impact to various environmental impact categories. This will be useful in aiding farmers in selecting processing systems for targeted outcomes in terms of nutrient separation and environmental outcomes.
Authors
Presenting & corresponding author
Rebecca A. Larson, Professor, Nelson Institute for Environmental Studies, University of Wisconsin-Madison, rebecca.larson@wisc.edu
Additional author(s)
Tyler Liskow, Engineer, Nelson Institute for Environmental Studies, University of Wisconsin-Madison; Brian Langolf, Researcher, Nelson Institute for Environmental Studies, University of Wisconsin-Madison; and Horacio Aguirre-Villegas, Scientist, Nelson Institute for Environmental Studies, University of Wisconsin-Madison
Additional Information
https://dairy.extension.wisc.edu/articles/treating-manure-to-produce-clean-water/
Acknowledgements
Newtrient and the USDA NRCS Conservation Innovation Grants for the funding to complete system sampling.
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