"NEWIR Manure" is a collaborative, multidisciplinary project involving the University of Nevada at Reno, the University of Florida, California State University, Chico, and Universidad Autonoma de Madrid (Spain). The project addresses a challenge of modern agriculture: sustainable manure management at large-scale concentrated animal feeding operations (CAFOs), and it requires significant interaction between engineers, social scientists, and animal nutrition scientists. The growth of CAFOs has enabled greater production of dairy products and meat, but it has also generated significant environmental impacts associated with manure disposal and management. A major concern is the pollution of ground and surface water supplies that are critical in arid regions such as Nevada and California. The team is developing a new technology to recover nutrients from manure using novel thermochemical and biological conversions to an algae-based cattle feed. The technology simultaneously recovers and exploits energy to generate heat and power. The quality of the feed product will be evaluated in an artificial rumen system. The technology will be analyzed by life cycle assessment (LCA), to better understand environmental impacts, and by economic analysis that considers the societal benefits from improved environmental performance. The project will train a diverse future STEM workforce through an REU for students at California State University, Chico (a predominantly undergraduate, Hispanic-serving institution) to study at the University of Nevada at Reno, an international scholar exchange, and the direct training and mentoring of five Ph.D. students.
In the NEWIR innovation, manure is processed by hydrothermal carbonization (HTC). In the presence of selected metal oxides, phosphorous and nitrogen are selectively partitioned to an aqueous phase, along with significant organic content. Carbon is left behind as a char that can be converted to heat and power by gasification and subsequent generation. Algae can be grown in the aqueous product of HTC, making use of the organic content and nutrients. Two well-studied heterotrophic microalgae strains, Chlorella vulgaris and Chlamydomonas reinhardtti, along with the well-known dietary supplement blue-green algae strain Spirulina maxima, will be evaluated. The algae serve as a high-value, nutrient-dense feed additive for cattle that can be blended with low-cost crop residues (e.g., corn stover) to provide a nutritious feed. Animal scientists will evaluate the feed via a well-established in vitro dual-flow continuous culture system for nutrient utilization and digestibility. Water is recycled for microalgae growth, and non- recovered water will be purified via direct contact membrane distillation for onsite reuse in sanitation and sterilization. LCA will be applied to evaluate environmental impacts of integrated resource recovery from the NEWIR process compared to conventional manure management practices, and benefits are anticipated through reduction of key life cycle impacts (e.g., carbon footprint, eutrophication, water depletion, and embodied energy). An economic analysis will be performed based on engineering, feedstock, animal nutrition, lifecycle cost analyses, and regulatory requirements to provide insight into the obstacles and opportunities facing producers and policy makers. This project has the potential to improve the sustainability of large CAFOs by turning waste products into assets while reducing environmental impacts. Adoption of the NEWIR process could significantly reduce the environmental footprint of dairy and cattle feed operations, with resulting benefits to surrounding communities and increased food production capacity.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
