Mabton dairy goes hi-tech in manure recycling effort


Manure from the Mensonides Dairy near Mabton is now recycled, as dairyman Art Mensonides has invested in a manure separator that can produce everything from compost to irrigation water.

MABTON - The Mensonides Dairy in Mabton has joined the digital age in recycling its manure, a process that separates water and solids in a multi-step process.

The resulting clean water can be reused for irrigation, conserving groundwater.

In addition, the process provides bedding and even a high-phosphorous, low-nitrate compost that dairy owner Art Mensonides can sell, creating a market for his manure. "Nothing goes to waste," he smiled.

"We undertook this project because we wanted to do something that was environmentally friendly," said Mensonides. "I don't have a lot of land and if we put all of our cows' manure on the fields we'd be over applying the nutrients."

Over-applying nutrients, he adds, can harm the corn crops he grows for feed.

The Mensonides Dairy began operations in 2002, and Art says he's been interested in finding a way to better process the manure it produces.

That led him to a $1.5 million investment in having the separator installed. The system has a primary separator that extracts solids for cow bedding while second and third stages extract material for compost which will be shipped out of the Yakima Valley for use on the high-value crops in the Columbia Basin.

"The result is a concentrated organic product which means orchard and vineyard growers don't need to make as many trips down narrow rows to fertilizer their crops," said Stuart Turner, who has been a board certified agronomist for 29 years and has operated Turner & Company, a scientific and technical consulting company in West Richland, since 1991.

Turner manages environmental and regulatory compliance for the Mensonides Dairy. The separator project was a natural extension of ongoing discussions to improve the facility.

Manure is pumped from the free stall area - the lowest point on the dairy - where the cows move freely. Two pumps push the manure through two 10-inch pipes up to the separator, which is housed in a 6,400 square foot building.

There the material goes into a primary separator, which is essentially a self-cleaning, screened rotating drum that collects the largest solid matter. Then a mechanized roller is used to compress the manure and extract the water.

The solids are spread out on a hard surface and dried for two days to a week (depending on the weather) before it is ready to be used as bedding for the dairy's cows. The process extracts 75 to 80 percent of the liquid.

The remaining material then goes through a secondary separator, with a minute screen mesh where smaller solids are captured. A high-tech centrifuge catches even finer solids high in phosphorus and nitrogen. This end material is composted for fertilizer, which the dairy hopes to sell.

"The organic fertilizer has a slower release of nutrients which reduces leaching, protecting the groundwater," said Turner, who has been working with Mensonides on the separator project for three years with construction beginning late last fall.

The remaining water is recycled and used to flush out the free stalls and to help irrigate the 600 acres of corn that helps feed the dairy's 5,000 cows. Between the extraction and reuse, the recycled water - referred to as a "green tea" - is usually stored in one of two storage basins - there are four available. Some of that green tea also waters and fertilizes several hundred acres of a neighbor's farm.

"At the end of this process you have clarified water which means a huge reduction in the air emission signature," added Turner.

The clarified water is just one treatment step from being able to be used to water city parks.

Lynden-based Daritech has installed six manure separators at dairies in Washington state, but Mensonides is the first in the state to utilize a centrifuge that further refines manure processing.

Karl Wight of Daritech estimates the centrifuge can pull up to 2,000 G's. That final step, he adds, ensures 95 percent of the solids from manure are removed. Minus the centrifuge that figure is closer to 60 percent, Wight says.

He notes that settings for the input and output of the separator are computer controlled at the site. The settings can be adjusted remotely by computer, tablet or even by smart phone.

Also, there's a generator on standby to operate the system if there is a power failure. Once the manure arrives at the separator many of the processes are driven by gravity - conserving energy.

One major advantage is the entire building is heated naturally and insulated so it can run year round.

Mensonides feels that other dairies in the region will adopt the separator technology in the near future.

"When we started our dairy nobody really knew how to handle manure," said Mensonides. "Now, dairy farmers are doing a lot of different things with manure and we know how to handle it."


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