Jacquline Mullin

If asked to identify what food waste item can be used in simulated wood products, environmentally friendly biofuel and as an additive in beauty products pecan shells do not automatically come to mind. Pecan waste is however extremely versatile, allowing it to be deemed a valuable commodity by a wide variety of industries.

It is the unique shape of pecan shells that allow them to have an unusual, flexible and ultimately, desirable cell design. Known as sclereids, pecan shell cells are round instead of the more common straight structure. The circular shape enables sclereids to more easily integrate with other materials when mixed in, thereby increasing their usefulness. Moreover, the minimal amount of ash in pecan waste allows it to be a less coarse fibre.

The level of processing applied to pecan shells is determined by the intended use of the product. Less processing allows pecan waste to be used as natural, biodegradable garden mulch or as an active ingredient in a compost bin. When turned into a fine flour, environmentally aware casting companies can use pecan shells, a natural ingredient, to thicken liquid latex or as part of the process of casting resins.

Pecan waste is also being used in the bioenergy field. Identified as a viable and easily accessible ingredient, a Denver-based energy company has added pecan waste to its supply chain. Pecan shells will be used to create electricity within a closed-loop process that feeds all energy back into the system and results in no unusable waste.

A new ingredient in the company’s repertoire, pecan shells will be converted into renewable energy through the process of thermal conversion. Energy generated will be easy to transport, with the level of megawatts determined by the needs of the customer. This technique is already being used to transform other types of nut shells into renewable energy.

The one by-product of the pecan and biofuel partnership will be organic biochar. An aid to the farming industry, organic biochar is used as a plant fertilizer and helps soil to retain moisture, lessening the impact of dry spells and aiding plant growth and crop yields.

Beneficial to residential consumers in the form of mulch or large industries as biomass, pecans are a food item with an inherent value that extends beyond just being a delicious treat. The ability to repurpose pecan shells not only removes them from the waste stream thus reducing waste and helping combat climate change, but also provides a flexible, practical and ecofriendly resource.