Laura Díaz Muñoz, winemaker and general manager at Ehlers Estate in Napa Valley, is passionate about worms. They factor deeply into the notable focus on sustainability at Ehlers, a 130-year-old, certified-organic, family-owned property. It all begins with water.
“We’re installing a new water treatment system that uses worms to process the wastewater, and I’m really excited about it,” Díaz Muñoz says. “It will allow us to treat all the wastewater we use in our facility without chemicals and produce water that’s clean enough to irrigate the vineyards and the landscaping.”
Indeed, Diaz Munoz is one of many winemakers and growers in California and throughout the West who are discovering that worms make a surprisingly effective ally in the quest to buttress winery operations against climate change.
At Ehlers, the unusual process comes courtesy of Chilean environmental engineering startup Biofiltro, a pioneer of vermifiltration—aka worm-based biofiltration—in the form of the company’s patented Biodynamic Aerobic System (BIDA). Harnessing the digestive power of millions or even billions of earthworms together with beneficial microbes, the system removes up to 99% of contaminants without the need for chemicals, Biofiltro claims.
Feeding on the grape skins, seeds, sugars and other organic compounds in winery gray water, the worms generate nutrient-dense worm castings, a rich source of fertilizer. Best of all, the worms work their magic in a matter of hours with little energy required, unlike the most common rival system, aerobic filtration ponds, which typically draw power from the electric grid to pump and circulate the water.
The Down Low on Vermifiltration
BioFiltro’s process isn’t unique. Vermifiltration has been around since the early 1990s, when researchers in Chile began studying and promoting it as a low-cost, low-tech method to treat agricultural wastewater and sewage. However, the method only began to gain traction internationally in recent years, and while a few small companies provide similar systems in New Zealand, India and elsewhere, BioFiltro is currently the only company with offices and projects in the U.S.—and certainly the only one with a specialization in the wine industry. (Biofiltro also has more than 190 installations up and running around the globe, at dairies, waste haulers and facilities for processing meat, milk and other foods.)
“My company was contracted to do an analysis of the technology as an independent third party and I was impressed,” says wastewater specialist Ron Crites, the chief engineer for the environmentally-focused Brown & Caldwell Engineers. “They do a good job, and they’re very efficient and sustainable.”
Crites, who is also the co-author of the wastewater treatment guide Natural Wastewater Treatment Systems, adds that he’s impressed with the adaptability of the technology. Each individual system is optimized for the type of waste and level of treatment that a given winery, dairy or other agricultural customer requires. “It really is a green technology,” he says.
Five years ago in Mendocino, the sustainable winery Fetzer, a certified B corp and proponent of regenerative wine growing, installed the first BioFiltro BIDA system in the U.S. to treat 100% of its wastewater. “We specifically chose California as a [U.S.] landing point because the state has some of the strictest air and water-quality requirements in the world, and we wanted to demonstrate how our system performed under these requirements,” says Mai Ann Healy, BioFiltro’s Chief of Impact and Sustainability Officer.
Since then, nine wineries in California, Oregon and Washington have installed worm treatment systems, with at least ten more operations in the pipeline.
Worm Water Takes Wineries by Storm
Spread across five acres at the sprawling Parlier, California, facility of O’Neill Vineyards, what appear to be 12 Olympic-sized swimming pools are in fact sunken beds filled with worms. BioFiltro’s largest winery system to date, unveiled in September 2020, it’s capable of processing more than a million gallons of wastewater a day, and up to 80 million gallons a year.
“We try to take advantage of new innovations, and we chose the BIDA system because their worm filtration process is 100% natural and because of its low-energy requirement compared to similar systems,” says Phil Castro, O’Neill’s Senior Director of Winery Operations.
The O’Neill Vineyards system can treat up to 1.15 million gallons a day during peak harvest, but BioFiltro’s “wriggle rooms,” as they dub their modular systems, come in multiple sizes, the smallest treating just 500 to 750 gallons a day. This makes the systems appealing to smaller wineries, many of which have been quick to adopt worms in their facilities.
A newcomer in the Carneros region, Sleeping Giant Winery is one of the most recent adoptees, having just installed one of Biofiltro’s box modules in April. Another strong proponent of worm water, Frey Vineyards in Mendocino, began treating 10,000 gallons of its gray water a day in 2019.
Looking Toward the Future
With all but one of the past 11 years classified as drought years, and with 2020 and 2021 on record as the second-driest two year-period in California since record-keeping began in 1895, it’s no wonder that concerns about water are top of mind for growers. After all, vines aren’t the only things that need water. The entirety of the wine production process is water intensive. Water footprint studies show that it can take as much as 120 liters of water to produce just one glass of wine.
At Ehlers, Díaz Muñoz believes the BIDA system will be a key component of the winery’s strategy for coping with drought and rising temperatures, as well as efforts to serve the growing number of visitors who come to savor the winery’s vintages in the high-ceilinged stone tasting room.
“Water is the number one resource that we need to be concerned about, that’s for sure, and we want to make sure that the water that goes back into the soil is the best quality possible,” Díaz Muñoz says.
“It’s not just about farming, there’s the social aspect of being a good steward of the land and member of the community. At the end of the day, we’re pumping groundwater and we all need to do our share to conserve it and make sure it lasts.”
Last Updated: May 9, 2023
