Earthworms like these are the "heroes" helping dairies, wineries, and others deal with waste water ... [+]
Charles Darwin once said of earthworms: “It may be doubted whether there are many other animals which have played so important a part in the history of the world.” When Darwin said that he probably couldn’t have imagined the interesting new “job” that earthworms are being asked to perform. They play a key role in a technology called “vermifiltration” which was developed by a company in Chile called BioFiltro. This article will describe the experience of two of the early adopters of this technology including a dairy in Eastern Washington and a winery in Northern California.
Dairies and wineries are both quality oriented operations that convert cultivated crops into beverages we enjoy. There are certainly many differences between these two systems, but they share a common environmental challenge - what to do with the wastewater that is unavoidably generated along the way. At a winery a substantial volume of water is used to rinse the fermenters, storage tanks, and barrels to clean out the spent yeast and other solid materials left over at various steps in the winemaking process. At a dairy there is a good deal of liquid waste generated by the cows themselves and also during periodic cleaning of the barns. In both cases this results in a liquid waste or “effluent” that has to be dealt with on-site since it can’t just be sent down the sewer the way that it might be in an urban setting and it certainly can’t be sent directly into rivers. Typically the water is channeled into ponds or lagoons to allow the solid materials to settle out, but during that stage nitrogen can off-gas as ammonia (NH3) which can pollute the air and later be washed down in rain and contaminate bodies of water. Nitrogen and other nutrient escape can lead to “eutrophication” and it is a highly undesirable outcome. As you can probably imagine, there are also odor issues.
Dairies and wineries can use various methods to deal with their solid and liquid waste streams, but vermifiltration is another good option for those sustainability-oriented industries.
Washington State dairy farmer Austin Allred walking by vermifiltration facility where effluent is ... [+]
Austin Allred is a family farmer in Eastern Washington who has owned and operated the 6,000 cow Royal Dairy for the last 8 years. Allred also grows forage crops like grasses and alfalfa in a 5 year rotation and then his dad grows potatoes in the 6th year. Having a sustainable and climate-action orientation he employs minimum tillage and uses composted manure from the dairy operation to increase soil health and to build soil carbon over time. But like any dairy there is the issue of the “non-stackable” manure and barn flushing water that is being generated throughout the year. Instead of putting this into holding lagoons, Allred now puts it through an initial filtration step to get it clarified enough so that it can be put through sprinklers. Those are set up on a shallow pond structure that has an impermeable bottom liner, a layer approximately 1.5 feet of local rock and 3.5 feed of local wood chips. The chips are sourced from local, “retired apple trees” which might normally have just been burned.
Royal Dairy farmer Austin Allread checking on the worm population in his BioFiltro vermifiltration ... [+]
A starting population of earthworms is added to the system and the effluent water is sprinkled over it for about 10 minutes every hour. The worms suck up the water as it flows over them and the bacteria that live in their guts convert ammonia and other forms of nitrogen into nitrogen gas (N2) which is the harmless form of that element that makes up 78% of our atmosphere. Also, because this system is “aerobic” (there is plenty of oxygen available), there aren’t emissions of the greenhouse gas, methane. The worms absorb most of the other components of the effluent which they use to grow and multiply. The population of worms can increase rapidly and soon the effluent water can run through the “vermifilter” and come out pure enough to use as irrigation water for the forage crops or as drinking water for the cows. After a couple of years the wood chips are largely broken down and are rich in worm castings.” Every two years the top two inches of that material can be “harvested” as a valuable fertilizer and source of beneficial microbes that can be sold for soil remediation on degraded land sites within the region. Some of the worms are retained to add to new wood chips and repeat the process. The total area needed for this process is about 8 acres and it has proven to be methane and odor free.
Dr. Frank Mitloehner is a researcher at the Clear Center at the University of California Davis, where he works on strategies to reduce the environmental and carbon footprint of animal agriculture. He heard about the vermifiltration process and was initially skeptical of the claims. But after conducting a 2-year study in which he measured all the key environmental parameters, he was actually “astounded” at the results. What the research showed was that the system dramatically reduced ammonia emissions and also eliminated emissions of the very potent greenhouse gas, nitrous oxide. In California he said that the worm castings would be worth $500 per cubic yard for use in horticultural crops. Dutch dairy farmers are protesting
government plans to limit nitrogen emissions that could drive many of them out of business. Mitloehner thinks that vermifiltration would be a solution that could allow them to continue to operate.
The vermifiltration facility that processes the waste water from the Bonterra winery
There are several wineries listed on the BioFiltro website who have started using vermifiltration for their equipment rinsing effluent. Bonterra Organic Estates, formerly Fetzer Vineyards, was one of the earliest adopters of the technology. Joseph Brinkley, the Director of Regenerative Farming, described this as a natural extension of their overall sustainability orientation which also involves minimizing soil disturbance and building soil health. Previously the winery had used a series of four settling ponds to transition the effluent into water that would be suitable for irrigating the vineyards. Using the same worm/wood chip/sprinkling system described above they were able to reduce that are by around 50%. With the value of land in a premium wine grape growing area that is a significant gain. They are able to use the worm castings and decomposed wood chips in their vineyards or sell them to others.
Another vermifiltration facility at the very large-scale, O'Niell winery in Parlier, California.
Other industries that use or are investigating this technology include aquaculture, slaughterhouses, waste haulers and food processors. On the Biofiltro site there is a listing of some of the other companies and other entities that are involved
