Cows outnumber Kiwis here in New Zealand. It’s close, but there are more dairy cows than there are people in our country.
The big herds are fine with us because their production drives much of our economy. New Zealand may look isolated on a map, adrift in the south Pacific Ocean, but we are a trading nation that constantly exchanges goods and services with the rest of the world—and about a quarter of our exports come from dairy farms.
As we continue to build our country’s dairy production, we’re also determined to lead the way in sustainability through technological innovation. Our future depends on it.
Cows generate methane, which contributes to the rising temperatures of climate change. Dairy farmers in New Zealand, therefore, have an obligation to come up with creative solutions to this problem.
We think we have found one, thanks to EcoPond, a treatment system that removes almost all the methane emissions from effluent ponds.
An ordinary dairy cow on a typical day produces about 70 liters of effluent, which is a euphemism for waste, which is a euphemism for words that I’m not going to print.
Traditionally, a cow’s effluent flows into a stabilization pond, where it receives treatment before its release. On our farm, we use much of this liquid to feed our soil.
This process works well, but one of the byproducts of effluent ponds is the release of methane into the atmosphere. So effluent ponds can create a challenge—but they also represent an opportunity to do better.
In a research breakthrough driven by a collaboration between farmers and scientists, a co-op called Ravensdown partnered with professors at Lincoln University on New Zealand’s South Island to create EcoPond, a product that could transform effluent treatment everywhere. We’re one of two dairy farms that are now experimenting with EcoPond. Ours has 1,100 cows and exclusively produces milk.
The concept of EcoPond is simple. It intercepts effluent as it drains out of a cowshed and pumps it into a mixing coil, where it receives an injection of iron sulfate. Then the effluent flows into what by outward appearances is a standard effluent pond. But this is an effluent pond with an important difference: The iron sulfate makes it impossible for microorganisms to emit methane.
“What we found is the EcoPond technology can reduce methane emissions by 99.9 percent,” says Hong Di, a scholar of soil and environmental science at Lincoln University.
He adds, with a smile: “We’re still working on the 0.1 percent. We’ll get there.”
EcoPond delivers additional benefits. It reduces the leaching of phosphate and E. coli by 90 percent or more. It improves the carbon content of our soil. And it even smells better than a traditional effluent pond.
It’s also easy to operate. After setting it up, farmers don’t have to give it much attention. The system monitors iron sulfate levels on its own and makes necessary adjustments.
For all its advantages, however, EcoPond is only a partial solution to the challenge of cutting methane, which has many sources on dairy farms, including cow burps.
We’ve discovered during our trial period that EcoPond wipes out about 8 percent of our total methane emissions. This is an excellent result, but not a complete strategy, as we’re aiming to cut emissions by 35 percent by 2035. We’ll need to look beyond our effluent ponds to achieve the next 27 percent.
I’m confident that we can get there, but I also expect to try a lot of methods. One is to alter the mix of microorganisms that assist with digestion in the bellies of cows. Right now, these bugs emit significant amounts of methane. By changing the diets of cows, we will be able to maintain their nutrition and cut methane emissions at the same time.
Separately, we’re trying to improve our sustainability by shifting away from electric power and taking up renewables such as solar and hydro.
For now, we’re pleased with the start that EcoPond has given us—and confident that new technologies can build upon this success and take us the rest of the way.