Water Resources Research Act Program

Details for Project ID 2016SD258B

Evaluating the Potential of Duckweed for Nutrient Capture and Use in Midwest Livestock Production

Institute: South Dakota
Year Established: 2016 Start Date: 2016-03-01 End Date: 2017-02-28
Total Federal Funds: $9,054 Total Non-Federal Funds: $18,128

Principal Investigators: Erin Cortus, Lin Wei, David Casper, Julie Walker

Abstract: There is a continuous need to identify, evaluate and optimize cost-effective means for cleaning impaired water. By producing a valuable by-product in the process of cleaning water, there are opportunities to alter the cost-benefit ratio of new technologies and enhance adoption of practices. Duckweed is recognized as a small, floating aquatic plant with a propensity to grow under a relatively wide range of physical and chemical conditions, while removing nutrients and metals from the supporting water. The Phosphorus Removal Facility on Lake Kampeska, South Dakota reported a large, unintended growth of this “weed” in a facility designed for algae growth, which prompted the investigation of biomass use, and potential inclusion in local livestock diets. Given the potential environmental and economic benefits, this project is designed to promote further understanding of the opportunities and challenges for duckweed growth systems in South Dakota and the Midwest region. This project is designed for a multi-disciplinary team approach, centered on lab-scale experiments and team-level design meetings, to identify the research gaps and opportunities for larger-scale funding initiatives, including feed trials, implementation and demonstration sites, and optimization studies. Experimental and modeling work will be conducted by undergraduate research assistants (URAs), with the supervision of an advisory team including animal scientists and engineers. The project scope will be limited to primarily bench and lab-scale work to address three objectives. These include: (1) identify the range of suitable conditions for duckweed growth, and limitations imposed by Northern Great Plains climate; (2) evaluate the digestibility of duckweed inclusion in silage; and (3) develop a baseline model for processing duckweed into useable formats for livestock feed. Tasks include a literature review and factor analysis (Objective 1), mini-silo tests to evaluate silage opportunities (Objective 2); and a group-based brainstorming activity and model development (Objective 3).