Manitoba Agriculture, Food and Rural Initiatives

NEWS RELEASE

INNOVATIVE IDEA: CREATING NEW SOURCES OF INCOME

 Click here to view Phosphorus video

 A University of Manitoba research team is attempting to recover phosphorus from liquid hog manure, creating a valuable slow-release fertilizer and a new source of income for hog operations.

“Our purpose is to look at existing manure managements systems in Manitoba, which are primarily lagoon based, and turn them into phosphorus mining operations,” says Associate Professor Nazim Cicek with the Department of Biosystems Engineering. 

In 2008, Cicek received project funding from the Agri-Food Research and Development Initiative (ARDI) to explore the feasibility of installing farm-scale reactors at hog operations to strip out phosphorus and other nutrients from swine lagoons.

The goal is to produce a slow-release fertilizer called struvite, composed of nitrogen, magnesium and phosphorus. Struvite is widely used in the turf industry, where it can be applied at high rates without damaging plant roots. Struvite prices have ranged from $400 to $1,500 per ton.

“In the research lab at the university, we have found that it is possible to take the liquid portion of the hog lagoon and get this high quality fertilizer out of it,” says Joe Ackerman, Ph.D. student and a member of Cicek’s research team. “This summer we wanted to use real-world quantities and see what sort of product we got at the end.”

Ackerman spent the rainy summer of 2009 travelling back and forth to a hog lagoon site in rural Manitoba to test the dynamics of the crystallization process in the field. With a focus on keeping costs “super low,” Ackerman installed two 500 L holding tanks on a small wooden platform and installed a series of hoses to pump liquid manure into the tanks.

Each visit, he would fill the tanks with slurry and add sodium hydroxide to the mix to facilitate the separation of nutrients from the organic solids.

After allowing the sludge to settle overnight, Ackerman would return to the site to pour the material into finely woven mesh bags in order to separate the excess liquid from the struvite crystals.

“We are trying to optimize the process so that farmers can go about recovering this material in a cost effective manner,” says Cicek. “We want to come up with a cost analysis that would suggest at what cost breaking point for phosphorus fertilizer would this become a reasonable alternative for the farmer and actually become a revenue stream.”

Benefits of phosphorus recovery

Of course, the removal and recovery of phosphorus from animal waste streams has benefits beyond the economic advantages that might accrue to local livestock producers.

The removal of phosphate in the crystallization process reduces the phosphorus-to-nitrogen ratio in the remaining manure to one more closely required by crops. As a result, the likelihood of surface runoff and phosphorus loading to Manitoba’s waterways is reduced.

And, in a small way, projects like this one can contribute to preserving global phosphorus stocks. Although phosphorus is an essential part of human, animal and plant diets, supplies of phosphorus are not unlimited.

The phosphorus in fertilizer comes from rock phosphate, which is mined primarily in China, the United States and Morocco. Some experts believe these available reserves will be depleted within 50-100 years at current usage rates.

“You’ve heard about peak oil?” asks Ackerman. “Peak phosphorus is coming. It’s going to be more important than peak oil because there’s no substitute for phosphorus.” 

Part of the trouble is that much of the world’s phosphorus is not available for use. Large deposits of phosphorus can be found on the ocean floor, for example, but no one has found an economical way to mine these deposits and use them in the production of phosphate fertilizers for agriculture.

Technology used by municipalities

This looming global shortage of phosphorus explains why researchers the world over have been experimenting with phosphorus recovery methods from municipal wastewater treatment facilities. Urine is an extremely concentrated source of phosphorus, but most of it is flushed away, eventually winding up in the ocean.

Since 1997, the City of Edmonton’s Gold Bar wastewater treatment plant has been successfully removing phosphorus and other nutrients from municipal biosolids and recycling them into struvite.

The municipal plant uses technology developed by Ostara Nutrient Recovery Technologies Inc. of Vancouver. According to the company website, the technology recovers “more than 90 per cent of the phosphorus and 20 per cent of the ammonia from wastewater that would normally be recycled back to the plant from the solids processing.”

Ostara is contributing to the research effort in Manitoba, acting as an industry partner offering technical support and advice. After collecting a summer’s worth of samples, the research team is beginning to analyze its product. The initial findings seem to indicate that the team did not collect pure struvite, meaning that the mix of nitrogen, magnesium and phosphorus is not quite where it should be.

Cicek and Ackerman are already making plans to continue the research next summer at a covered lagoon, which will influence the characteristics of the effluent they collect. The team is singularly focused on developing a high-quality product using simple and low-cost production methods.

“If there’s a way that farmers can make some money out of what’s normally wasted, it’s good for them,” says Ackerman. “It’s good for the environment, good for global phosphorus stocks and good for the farm economy. It seems like a win-win-win.”

The article was originally published in the winter 2009/10 issue of Farmers’ Voice.

To read more on this project please click on Project Number 08-907