Carbon Offsets Could Reduce The Stink From Manure Lagoons

“Ninety-five per cent of the odour is gone.”

– LEONARD HOFER

Cutting the stink from manure storage lagoons doesn’t earn farmers a cent, but capturing and destroying the methane lagoons create might.

Preferred Carbon, Farmers Edge Precision Consulting, the University of Manitoba and Starlite Colony have set up a pilot project to study to see if it pays to capture methane and odour. A low linear polyethylene cover was recently put over the colony’s 200×350-foot lagoon.

They hope the cash earned from selling carbon offsets for destroying methane, a greenhouse gas 21 times more potent than carbon dioxide, could make lagoon covers an affordable option for producers.

ODOUR GONE

“Ninety-five per cent of the odour is gone,” said colony member Leonard Hofer during a recent tour of the site.

There’s still a slight whiff of hog manure coming from two smaller nearby lagoon cells covered with straw for odour control.

The lagoons hold the manure from the 13,000 to 17,000 hogs the colony produces in its farrow-to-finish operation annually, as well as from 12,000 layer hens.

Hofer likes the odour control, but said it’s only practical if the cover is affordable.

It’s no secret that manure smells. What is less well understood however is how much methane is produced under field conditions. Answering that question is a prerequisite to establishing the value of the carbon offsets farmers will be paid, said Bruce Love, a director with Calgary-based Preferred Carbon.

MONITORING

The data needs to be verifiable and independent. That’s where the University of Manitoba enters.

Monitoring equipment (solar powered, consistent with the “green” theme) has been set up at the site, as well as a system for burning the captured methane. When burned, methane converts to carbon dioxide and water vapour.

If there’s enough methane captured the colony might use it to heat a greenhouse, Love said.

The methane could also be used to heat the lagoon during colder times of the year resulting in more even methane production throughout the year.

“This is not exactly new technology, but still early days when it comes to carbon offsets,” Love said. “We see carbon offsets like a new crop or another commodity for farmers to earn revenue from.”

A new carbon offset market is operating in Alberta and Saskatchewan and has started work on one, but Manitoba is lagging behind, as is Canada in general, Love said.

REDUCING CO2

The goal is to efficiently reduce the amount of carbon dioxide and other greenhouse gases linked to climate change going into the atmosphere. In some cases it’s easier and cheaper for farmers to change the way they handle manure or fertilizer than it is for so-called “large final emitters” such as an oil company. So it might choose to pay farmers to reduce their carbon contribution and still be money ahead.

The type of “positive-pressure” lagoon cover used here costs around $17 a square metre and should last 10 years, said Roy Farrow, another Preferred Carbon director. He declined to reveal how much the pilot project will cost.

Most manure covers are “negative pressure.” Methane and the smell are drawn into the atmosphere through filters, which cut the odour, but not the greenhouse gas emissions.

The cover here is strong enough to walk on and doing so is comparable to taking a stroll on a giant waterbed. The cover weighs 60,000 pounds and another 70,000 pounds of weight are added to hold the cover down when methane is produced.

INNOVATION

James Hofer, who manages the hog operation here, said the cover is a great innovation, but the public can’t expect every hog farmer to run out and install one.

“We do good, and when we know better, we do better,” he said, adding that replacing old technology with new takes time because of the cost.

Farmers Edge, a Manitobabased firm with 40 consultants across Western Canada specializing in precision-placed fertilizer is Preferred Carbon’s link to Manitoba farmers, said Farmers Edge Precision Consulting agronomist Brunel Sabourin.

Using fertilizer more efficiently will give farmers better yields and lower costs, but might also earn them revenue through carbon offsets, he said.

Preferred Carbon and Farmers Edge have another pilot project called “Spring Empty,” where farmers get carbon offsets for emptying their manure lagoons and spreading the manure in the spring.

Spring, rather than the more common fall manure application, is a more efficient way to apply nutrients, Love said. For example, it reduces the amount of nitrous oxide going into the atmosphere.

Nitrous oxide is 310 times more potent as a greenhouse gas than carbon dioxide. That means preventing a tonne of nitrous oxide from getting into the atmosphere is like cutting 310 tonnes of carbon dioxide. [email protected]

About the author

Reporter

Allan Dawson

Allan Dawson is a reporter with the Manitoba Co-operator based near Miami, Man. Covering agriculture since 1980, Dawson has spent most of his career with the Co-operator except for several years with Farmers’ Independent Weekly and before that a Morden-Winkler area radio station.

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