Dairy farms fight pollution, turn manure into cash
Managing manure is nothing new for dairy operators. After all, cows and their four-chambered stomachs are one of nature’s best examples of efficient digestion.
But these days, those bovine digestive systems are generating a new source of income for nearly 200 dairies in California.
At his River Ranch Farms in Hanford, Jack de Jong now counts on the thousands of gallons of milk his 5,600 Holstein cows produce each day and the thousands of pounds of manure they excrete. Each product is important to his bottom line.
While his milk is turned into a variety of dairy products at the nearby Land O’ Lakes cooperative in Tulare, River Ranch Farms’ other commodity is flushed from its two milking barns. The cow droppings take a systematic journey across the 2,100-acre dairy. They go from a manure separator to a weeping wall and eventually land in a large, rubber-covered anaerobic digester.
Bacteria break down the manure solids, and emissions that would normally escape into the atmosphere are captured. The biogas byproduct, methane, is an energy-rich fuel. It is deposited in a pipeline that runs beneath the dairy to a biogas cleaning hub a few miles away.
The hub, funded in part by a grant from the California Department of Food and Agriculture Dairy Digester Research and Development Program, is owned by a partnership of dairies and Maas Energy Works, a digester developer, operating as Lakeside Pipeline LLC. It is already collecting methane from five dairies and can accommodate three more, for a total of 33,500 cows, de Jong said.
“Historically, I’ve entertained the idea of making money from manure, and initially, I was not excited,” de Jong said. “There has been hesitancy getting to this point, but as understanding of the situation increases, so does the comfort level.”
The gas leaves the digester at about 65 percent to 67 percent methane, but once it cycles through the hub, methane percentage reaches 98 percent, de Jong said.
The methane is purchased by Southern California Gas
Co. It enters its pipeline and is used to power a variety of renewable natural gas projects such as fueling fleets of trucks or buses. Carbon credits earned by the dairies are shared by the gas company and Maas Energy Works.
Managing manure has taken on greater urgency in the past several years with passage of Senate Bill 1383, legislation in 2016 aimed at curbing pollution from methane. As a result, the California Air Resources Board implemented strategies to reduce emissions from dairy manure by 40 percent by 2030.
To accomplish this, the state has incentivized the process of capturing manure’s release of methane with competitive grants through its dairy digester research effort and its Alternative Manure Management Program. These efforts recently gained traction as important steps in battling climate change and providing business opportunities for dairy operators.
“The state grant process has used the carrot versus the stick principle to encourage us to use the technology available,” de Jong said. “I praise the state for doing that. By monetizing this, dairymen can get in at a lower cost and risk in a very quick time period.”
Scott Harrison, CEO of Figure 8 Environmental of Bakersfield, hosted a seminar titled “Monetizing Manure,” at the recent World Ag Expo in Tulare. Harrison’s firm designs, builds and manages manure processing systems for dairies. He encouraged dairies to think about how managing manure can help them comply with environmental, nutrient and wastewater regulations.
“If you can imagine what’s possible and see the bigger picture, there is a lot of value in manure,” he said. “Manure is a profit powerhouse.”
There are many other uses for manure. For years dairy farmers have been collecting it, storing it and using it as a renewable fertilizer. Operators of flush dairies can address operating costs with manure by using the wastewater to irrigate silage crops or almonds. When properly treated and mixed with well water, this saves on groundwater pumping costs and can address Sustainable Groundwater Management Act regulations.
Manure can also be upcycled into clean, new bedding for animals through a composting process. Some dairy operators such as de Jong also sell this compost to other farmers. Savings in these areas can allow dairies to maintain their herd sizes in light of pending SGMA restrictions.
“Drying of separated manure solids used to be a burden that increased our cost of business,” he said. Now that has been helped by compost sales.
Frank Mitloehner, director of the Clarity and Leadership for Environmental Awareness Center at the University of California, Davis, says 4% to 5% of all greenhouse gases are from agriculture “and dairy is the largest contributor within agriculture.”
But now there are 185 methane-reducing digesters listed in the state, according to the nonprofit organization Dairy Cares. There are also more than 300 operating in the nation, according to the U.S. Environmental Protection Agency.
“I anticipate this technology growing across the United States,” Mitloehner said. “California leads the nation, maybe the world, in this field.”
Each dairy is different and requires a tailored approach to its manure management. To that end, Mitloehner encouraged farmers to do their homework and understand the design and operation of their manure-management systems. He said many dairy farmers eventually hire out for this portion of their operations.
To encourage California’s smaller dairies—for which a digester may not be feasible— to reduce methane output, the state provides financial assistance for farm families as they reduce emissions through a variety of technologies and strategies.
A total of 114 projects have been awarded grants to date. For fiscal year 2021-2022, the state will be awarding $32 million in grants, with priority given to the Alternative Manure Management Program. Previous projects included mechanical solids-liquid separation with drying, conversion of flush systems to scrape with dry manure storage or composting, and compost pack barns.
Applications for the program are open through May, with CDFA working in partnership with UC Cooperative Extension to assist farmers needing help in the application process.
“This is not only climate smart, healthy agriculture, but it is good for the bottom line,” said UCCE dairy farm advisor Betsy Karle. “The opportunity is here.”