Renewables from manure

About 20 miles south of Green Bay, Wisconsin, sits a biorefinery that developers tout as an efficient and effective way to manage manure from dairy farms.

The BC Organics facility is unique not only in its scale, but also in the amount of manure it can process. Eleven dairy farms are participating in the project, delivering a daily total of nearly 900,000 gallons of manure from a total herd of about 30,000 cows to the 16 anaerobic digester tanks at the main facility.

Dynamic Renewables is the owner, developer, and operator of the facility, which held its ribbon-cutting ceremony in Nov. 2022.

“We are now processing manure from 11 different dairies, two dairies which pipe manure into the facility and nine more which truck manure to our facilities via tanker trucks,” says Karl Crave, executive vice president of special projects at Dynamic Renewables. “We collect manure at the site and process it into three products: renewable gas, dried fiber bedding, and clean water that can be discharged back into the watershed.” Concentrated nutrients from the digester are also collected and returned to the participating farms to use on their crops.

As Dynamic Renewables worked to get the BC Organics project off the ground, the company approached dairies in the area.

“Early on in the process, a core group was formed that saw the long-term goals, and we had a lot of open and honest discussions about what we were trying to do and how it fit into their operations,” Crave says. “Over time, additional farms joined, and a few decided not to participate. Each farm had a lot of discussion about where they will be as a business in five to 20 years and how BC Organics may fit into those plans. Most of our partner farms are multigeneration family-owned farms, and it takes time and some hard decisions for them to commit to their future and participation in a project like ours.”

Benefits to the farm

Wiese Brothers Farm, located half a mile from the Greenleaf digester site, is one of the participating farms. Wiese Brothers Farm built a holding tank, and BC Organics pumps manure via a dedicated pipeline. Dan Wiese, one of the family partners in the 6,000-head operation, says the farm was approached by BC Organics in the early planning stages of the digester. “It made sense to us,” Wiese says. “This project fit well into our operation and required minimal investment.”

Farm benefits are nutrient concentration, volume reduction, and dried fiber bedding. “Ultimately the goal is to provide solutions to nutrient-management farm problems, in addition to making renewable natural gas,” Crave says. 

How it works

The process begins by pumping the manure into a series of 16 digesters. The digester heats up to 100°F and mixes the contents. After about three weeks, the end product is a biogas that is further processed and cleaned, so it can be delivered to a natural gas pipeline and ultimately become fuel for vehicles.

Solids are further processed and dried into bedding that is sent back to the farms. Approximately 135 tons of bedding are processed each day.

Water is a main component of the process, and after moving through the digester it is further processed in a water treatment facility to remove suspended solids. “We essentially have several stages of filtration,” Crave says. “That leaves us with clean water that can be discharged back into the watershed or sent back to the local dairies for land application.”

BC Organics can trace its roots to 2017, when Brown County officials began studying the impact of manure on the local environment and watershed, and how producers could develop more environmentally friendly systems in which to handle the manure. “We responded with our proposal, and broke ground about 2 years ago,” Crave says. “After about a year of construction, we started pumping manure into the digesters. And now, we are making biogas as well as effectively meeting the needs of producers.”

Crave explains that the BC Organics plant is unique in the size of the project. “We have built and operated many similar projects, but this is at a much larger scale,” he says. “This project is helping farmers solve an issue. They are looking for tools to be better stewards. And this project is offering them a solution.”

While this project is massive compared to other manure digester facilities, Crave says what they are learning at BC Organics will have real-life benefits to facilities of all sizes. “This multi-farm facility is unique; we anticipate the technologies will scale down to smaller projects as well. There are certainly economies of scale, but a lot also depends on the existing infrastructure,” he says. “That ultimately means being able to get the renewable natural gas back into a pipeline, as opposed to having to transport it by semitanker.

“The existing infrastructure played a large part in this facility.” Crave says. “A large interstate natural gas pipeline is located nearby, so we were able to tap directly into that pipeline. That was a huge benefit for the long term, because that was much more economical than trucking.” 

A positive move

The privately owned project is backed by a USDA loan guarantee. A portion of the cost of the water treatment equipment was offset by a grant from the State of Wisconsin. The $15 million grant was awarded to Dynamic Renewables from the state’s Focus on Energy program to develop a community digester facility to reduce phosphorus runoff into the Fox River watershed.

Wiese says the project is a positive move for the dairy industry. “This project is a major step forward for sustainability for the dairy industry,” he says.

Crave says the company has worked closely with the local community in developing the project. 

“We’ve always been very transparent — from planning to operation. We had a year and a half’s worth of town board meetings and invited local residents to see some of our past projects,” Crave says. “A lot of what we do is try to educate on what’s happening and provide that information of how we are going to operate. We invite regular tours to the public, which can be booked online at dynamic-renewables.com.”