Researchers at Michigan State University have developed the technology known as the McLanahan Nutrient Separation System.
It takes an anaerobic digester a contraption that takes waste, such as manure, and produces energy as a byproduct and couples it with an ultra filtration, air stripping and a reverse osmosis system.
The result is water clean enough for livestock to drink, or, at the very least, to dispose of in an environmentally friendly manner, researchers said.
“If you have 1,000 cows on your operation, they produce about 10 million gallons of manure a year,” said Steve Safferman, an associate professor of bio-systems and agricultural engineering who is involved in the project.
“About 90 per cent of the manure is water but it contains large amounts of nutrients, carbon and pathogens that can have an environmental impact if not properly managed,” Safferman said.
While turning the manure into clean water makes environmental sense, the team also is conducting research on how it can make good financial sense for farmers. And in some cases it could have a significant impact on the long-term viability of the farm.
“Here in Michigan we have a tendency to take water for granted,” Safferman said. “But out west, for example, where drought remains an issue, the accessibility of clean water could make the difference between a farm remaining viable or going out of business,” Safferman added.
The process “goes beyond a typical digester,” said Jim Wallace, a former MSU student who earned his doctorate under the direction of Safferman and William Bickert, former professor of agricultural engineering.
It does this by extracting nutrients from the manure that can be harmful to the environment and can be re-used as fertiliser. “For example, we’re able to capture a large percentage of the ammonia that would otherwise be lost in the atmosphere.
Ammonia is a negative from an air-quality standpoint,” said Wallace, who now works for the McLanahan Corp, which is working to develop the technology.
Currently the system produces about 50 gallons of water from 100 gallons of manure. Wallace said the goal is to increase that number to about 65 gallons.
The Nutrient Separation System is expected be ready for commercialisation by the end of this year.