Earthworms ‘worm’ their way into sustainable dairy farming in Washington state
YAKIMA COUNTY, Wash. — The average earthworm can live up to eight years, eat its weight in food daily and breathe through its skin — it also just might be the future of sustainable dairy farming in Washington state.
International waste management company BioFiltro is helping dairies around the world use worms to turn manure into fertilizer and clean irrigation water.
Manure control— often referred to as nutrient management — has presented a challenge to dairies over the years. Dairy farmers have struggled to come up with cost-effective and sustainable ways to manage never-ending supplies of manure.
While manure — rich in nutrients such as nitrogen, phosphorus and potassium — is used as fertilizer, some dairies are producing so much that the supply exceeds the demand. The excess is often stored in manure lagoons until it can be used.
If dairies with limited storage capacity for their manure spread too much at a time or over apply in a particular area, the nutrients can seep through to the groundwater and into the local drinking water supply.
That application is strictly regulated by state and federal agencies, as the Environmental Protection Agency reports high levels of nitrates in the water can lead to negative health impacts.
BioFiltro takes a different approach. The beginning is the same: cows eat and excrete, water flushes the stalls and the solids in the manure are filtered out and composted.
The change in the process starts with what’s leftover once those solids are removed: liquid effluent or green water. Instead of being stored in lagoons, the green water is filtered through layers of wood chips, worms and rocks before reaching a concrete base.
As the green water travels through the filter, the worms eat up much of the nutrients, leaving the water clean for irrigation. When the worms excrete the nutrients, their castings can be used as fertilizer.
“We’re constantly trying to do things better and better,” said pilot project participant Jason Sheehan, who owns J & K Dairy in Sunnyside.
Sheehan began working with the company in the spring to bring in a small version of the biofilter to test it out.
“Any time you can be a part of something new that’s gonna be better for the dairies, better for the environment, better for water quality … I like to be part of the ground level,” Sheehan said.
BioFiltro began in the 1990s, as a biophysicist in Chile experimented with using earthworms and bacteria to treat wastewater.
The company now supplies wastewater filtration systems to food processors, sanitary waste, slaughterhouses, wineries aquaculture and dairies around the world.
One of the largest projects is at Royal Dairy in Grant County. Owner Austin Allred started with a two-year pilot project that processed about 5,000 gallons of green water per day, then expanded to a 200,000 gallon-per-day system.
On average, Allred says his system eliminates about 80 to 90 percent of the nitrogen, 70 percent of phosphorus and 50 percent of potassium.
Allred says dairy farms aren’t perfect, but that most are doing their best every day to take care of their animals and the environment they live in.
“There’s always bad actors … there’s gonna be the bottom of the barrel people that aren’t doing it right: nobody’s ignorant to that,” Allred said. “At the end of the day, we’re all trying to figure out what the best practices are.”
With dairies subject to increasingly stringent regulations and lawsuits by environmental groups, Allred said some people have misconceptions about the dairy industry.
“A lot of people have this idea that dairy farmers don’t love cows, which couldn’t be further from the truth,” Allred said.
The truth, Allred said, is that he and other dairy farmers love their cows. Not only that, but he said farmers never have to choose between caring for their cows and profits: a healthy cow is a productive cow.
“If you can’t accept that dairy farmers love their cows, then accept the fact that …it’s always in the best interest of a farmer to have a healthy, comfortable, happy cow,” Allred said.
Allred said he believes many of the lawsuits filed against small, family farms are less about saving the environment and more about shutting those dairies down.
“We take our stewardship over these animals really seriously and it’s not just doing what’s lawful, it’s not just doing what we see is right,” Allred said.
“It’s really personal for us … I feel that it’s a moral and even spiritual obligation that I have to take care of these animals and to do it in the best way I can.”
Allred says he plans to expand the project further, until it will process all the green water produced by the farm. He also plans to bring the project to his Moxee dairy.