INL partners with industry to dig deep into organic waste disposal

When most people think of tree nuts, they imagine a tasty snack — not the parts of the nut that get left behind. But for Houston-based startup Vaulted Deep, a fibrous byproduct from nut agriculture is one ingredient in a bold new approach to waste management. Thanks to a recent collaboration with the Idaho National Laboratory (INL), that vision is one step closer to realization.

Vaulted Deep has a novel goal: repurpose a technology developed for the oil and gas industry, called deep well injection, to permanently dispose of organic waste thousands of feet underground. For the nut industry, this approach would reduce the burden of managing hundreds of thousands of tons of hulls — the fleshy, protective outer layer of nut fruits that enclose the hard shell and the nut we eat — each year.

Traditional disposal options like landfilling or incineration are facing challenges that include tightening environmental regulations, shrinking disposal capacity and seasonal bottlenecks. Vaulted Deep’s geologic infrastructure offers a safe, year-round disposal pathway that can operate regardless of weather with the benefits of less processing and less delays. The process streamlines operations and avoids bottlenecks during the critical harvest window.

Vaulted Deep’s Great Plains Facility in Kansas. Photo courtesy of Vaulted Deep.

To refine its innovative technology for this specific waste, Vaulted Deep turned to INL’s Technology Deployment team. Technology Deployment specializes in helping INL researchers turn their inventions into commercialized products. They also help drive innovation through the U.S. Department of Energy’s Technical Assistance Program (TAP). Startup companies can receive up to 40 hours of laboratory expertise from TAP at no charge. This assistance helps them to handle technical issues beyond their ability to solve alone.

INL biomass researcher Luke Williams partnered with Vaulted Deep to explore methods for grinding solid organic waste material into ultra-fine particles. The aim was to optimize the material size for use in Vaulted Deep’s proprietary subsurface carbon storage process.

“Vaulted came to us with a clear challenge,” said Williams, a senior research engineer. “They needed to understand how different milling techniques would affect particle size, energy use and throughput. We were able to help them test multiple approaches and generate actionable data.”

Over the course of the project, INL researchers used different mill types to reduce the material in stages. They carefully tracked particle size distributions and energy requirements. The team also evaluated how long the material needed to stay in the mill to achieve the desired consistency, and whether additional methods like attrition or hammer milling might be worth exploring.

“This kind of collaboration with private industry is exactly what TAP is designed for,” said Jim Keating, who leads INL’s TAP work. “It’s about helping innovative companies move faster by giving them access to national lab expertise.”

The results were promising. Vaulted Deep now has a clearer picture of how to scale its process for commercial operations, and INL’s final report includes detailed recommendations for further optimization. Samples from the final milling stage were shipped to Vaulted Deep’s Great Plains facility in Kansas for more testing.

“Innovation doesn’t happen in isolation, and public-private partnerships have proven themselves to be a key component to innovation,” said Bryan Epps, Vaulted Deep’s head of Commercialization. “Working with a national lab like INL gave us the critical insights we needed to move faster while also giving us confidence that our approach can scale safely and sustainably.”

Vaulted Deep plans to move forward and apply this new form of innovative waste disposal to nut byproducts.