Almond shells can be processed to become an ingredient in such diverse products as flower pots and tires.The California Almond industry is faced with a growing amount of biomass in the form of byproducts (hulls and shells) and woody material from whole orchard removal. At the same time, options for productive use of almond biomass have dwindled, the result of a shrinking dairy industry, which uses almond hulls in animal feed and shells for bedding, and the closing of cogeneration plants, which use woody material for the generation of energy.
Almond Board of California (ABC) has taken note, supporting a wide variety of research projects to develop alternative uses of almond biomass. Reports on the current status of this research will be given at two symposiums during The Almond Conference, Dec. 6–8, in Sacramento.
Biomass: Building a California Bioeconomy with Hulls and Shells
Exciting “near-market” technologies could expand value-added options for almond growers and handlers, as well as contribute to zero waste. Ongoing research and commercialization efforts will be reviewed at this session for a range of options including sugar extraction from almond hulls, use of cellulosic nanofibers from hulls for the military, biochar production from almond shells for soil enhancement, biofertilizer conversion from a range of almond-based biowastes, and torrefaction of almond shells into biodegradable plastics.
“Almond hulls have useful, valuable sugars in them — fermentable sugars,” said Dr. Bill Orts, research leader, bioproducts, at USDA’s Agricultural Research Service facility in Albany, in a presentation at the Almond Board’s Food Quality and Safety Symposium in June. “This means they can be converted to ethanol and other valuable sugars.”
Almond shells can be burned in the absence of oxygen in a process called torrefaction to create a product that, when added to polypropylene in the making of flower pots and starter trays, helps the trays retain their shape. “The trays are a little stiffer and won’t melt in the sun, compared to other fillers used in this industry,” he said.
Another option Dr. Orts and his colleagues have investigated is the potential for using torrefied almond shells as an ingredient in all natural tires, replacing the carbon black derived from the petroleum and natural gas industries.
Attend this presentation by Dr. Orts for updates to this research and to learn about additional intriguing potential uses of almond byproducts.
Biomass: Utilizing Trees and Hulls in the Orchard
With changing markets for both orchard tree biomass and almond hulls, important questions have been raised about keeping markets open and finding alternative ways to utilize these materials. In this session, Kelly Covello, president of the Almond Alliance of California, will provide an update on discussions in Sacramento to keep traditional cogeneration energy plants open, and implications of Senate Bill 859, which includes a proposal to ensure that biomass facilities continue to operate as an integral piece of the state’s management of wood waste for the next five years.
Also in this session, researchers Brent Holtz, University of California Cooperative Extension farm advisor for San Joaquin County; and David Doll, University of California Cooperative Extension farm advisor for Merced County, will describe current research on alternative dispositions of woody biomass that may include soil health benefits. These include whole orchard recycling — incorporating chipped woody orchard material back into the soil prior to replanting, and the impact of returning almond hulls to the soil.
