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Dairy Farms Tap Into Anaerobic Digestion to Carve a Greener and More Financially Secure Path

The dairy industry is shooting to achieve greenhouse gas neutrality by 2050. Denise Barstow Manz, a seventh-generation family member at Barstow's Longview Farm in Massachusetts, tells Waste360 how dairy farms are working toward this goal. And hear why anaerobic digestion (AD) has been a big part of Barstow’s sustainability story over the past decade.

Arlene Karidis

June 7, 2023

5 Min Read
Bartow Farm
Barstow's Longview Farm

The dairy industry is shooting to achieve greenhouse gas neutrality by 2050.

Denise Barstow Manz, a seventh-generation family member at Barstow's Longview Farm in Massachusetts, tells Waste360 how dairy farms are working toward this goal. And hear why anaerobic digestion (AD) has been a big part of Barstow’s sustainability story over the past decade.

Waste360: What are some newer trends in dairy farming as they tie to sustainability?

Barstow Manz: Embracing technology is one essential part of it. Not only does tech make the job easier on our bodies and more efficient farms, it is better for our herd and planet. Here are a few examples: 

  • Robotic milkers allow animals to visit on their own schedule. A cow might visit three to five times a day to relieve pressure in her body. A more comfortable cow is healthier, easier to care for, produces more milk, and a higher quality milk. 

  • Better feed means better nutrition and easier-to-digest forage. Feed that is more consistent and more digestible produces fewer belly bubbles. Fewer bubbles equals less cow belches and reduction in enteric methane. 

  • Anaerobic digesters are becoming more accessible to small- and medium-sized dairy farms. Digesters that run on only manure (deriving the methane from it to make renewable gas) can only be sustained on massive dairy and swine farms. Digesters like ours also bring in food waste from local food producers, divert it from landfills, and mix it with our manure to create renewable electricity here on the farm. 

Waste360: How and why did you get into AD?  

Barstow Manz: In the early 2000s, the milk market crashed. This was a time that we, together as a family, discussed how we were going to continue farming. We needed to diversify. We planned to open up Barstow's Dairy Store and Bakery (which we did in 2008), and we started talking with four other Massachusetts dairy farmers about anaerobic digesters. With a group of us, we had a louder voice, which attracted the attention of legislators and investors. In 2013, the digester on Barstow's Longview Farm began operating. 

Installation of the digester came from the need for an additional revenue stream. But it was also an investment that spoke to what we believed as a family - that we could and should take measures to reduce our carbon hoof-print. This system fits well with the needs of our community and with our values as a family dairy. 

Waste360: Why capitalize on cow manure? What has it meant for your business?

Barstow Manz: It is no secret that cow manure is a miracle soil amendment. The anaerobic digester digests that manure and food waste more thoroughly, leaving us with a chemical-free fertilizer to spread on our 450 acres of farmland. 

Since the installation of the digester, we have seen increased crop yields, enhanced soil health, and we have decreased our chemical fertilizer usage about 90 percent.

Waste360: How were you managing your manure before you invested in AD?

Barstow Manz: Prior to the digester, we were still spreading our manure on the land. The digestion process reduces the odor. Before, we'd get about 20 phone calls a year when we spread manure. Now we get one or fewer complaints about smell each year.

Waste360: Can you speak on the contribution of agriculture waste to methane emissions?

Barstow Manz: Methane has a much shorter atmospheric lifetime than carbon dioxide (CO2) – around 12 years compared with centuries – but absorbs much more energy while in the atmosphere. The work farmers are doing to reduce and capture methane emissions will have dramatic effects in the near-ish future. Then the oil and gas companies will really be in trouble - instead of pointing their fingers at U.S. dairy (which produces about 2% of our nation's emissions) they'll have to find someone new to pick-on ha-ha. Transportation, industry, and electricity contribute to 76 percent of U.S. total emissions. 

Waste360: Why are farmers paying more attention to methane these days?

Barstow Manz: A lot of the demand for emissions reduction is coming from consumers. And that's a good thing! If we want a better world, we need to demand it. We also need to be willing to pay for it in the goods, services, and food that we buy.

Waste360: Enlighten us on the concept of sustainability being about doing more with less.

Barstow Manz: Dairy farmers have been doing more with less for a century. More food with fewer acres, more milk with fewer cows, and plenty of work with fewer dollars. Sustainability also means being able to sustain the family farm. It is a hard ask to expect your kids to pick a life of incredibly hard work to only scrape by. We need our food system to feed our community, but to do that, we need our family farms to be able to support the next generation. 

Waste360: How much energy are you producing and how is it used? 

Barstow Manz: The digester produces more than 5,100-megawatt hours of renewable energy a year. That is enough to power 1,600 homes based on what the average Massachusetts home uses for electricity in that timeframe. We only use three to eight percent of that on the farm, so the vast majority is going out into our community. 

Waste360: How much residue is left that is used for fertilizer?

Barstow Manz: About 98 percent of what we put into the digester comes back out, because we are just removing the gas in the process. All of it is intensely beneficial for our cropland. 

Waste360: In a nutshell: what do you see as the greatest payoffs of the anaerobic digester?

Barstow Manz: The anaerobic digester is playing an important role in our community by creating renewable electricity, contributing to soil health, and reducing reliance on fossil fuels. Additionally, it is a revenue stream contributing to sustaining a family dairy farm, which provides affordable, nutritious food for our community, keeps land open, and connects us with our New England heritage. 

About the Author(s)

Arlene Karidis

Freelance writer, Waste360

Arlene Karidis has 30 years’ cumulative experience reporting on health and environmental topics for B2B and consumer publications of a global, national and/or regional reach, including Waste360, Washington Post, The Atlantic, Huffington Post, Baltimore Sun and lifestyle and parenting magazines. In between her assignments, Arlene does yoga, Pilates, takes long walks, and works her body in other ways that won’t bang up her somewhat challenged knees; drinks wine;  hangs with her family and other good friends and on really slow weekends, entertains herself watching her cat get happy on catnip and play with new toys.

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