Waste-water management | Ostara’s patented Pearl process could help address phosphorus concerns in Lake Winnipeg
Isolating and transporting phosphorus and nitrogen has always been the Holy Grail for scientists trying to develop better manure management technologies.
If those two elements could be economically extracted and exported beyond the point of origin, pollution from manure could be nearly eliminated and commercial grade fertilizer could be sold at a profit far past the farmgate.
There was no problem incorporating manure into adjacent fields when livestock were raised on small farms scattered around the countryside.
However, an economic ring formed around each farm as the livestock sector intensified and animal numbers became concentrated in specialized facilities.
Hauling manure beyond that strict radius was economically prohibitive, regardless of what animals the manure came from or what form it was in.
The weight and volume of manure, in combination with its nutrient value, usually limits livestock producers to a transportation radius of less than three kilometres.
However, a Vancouver company says it can break out of that restrictive ring with a new process that removes 85 percent of phosphorus and 25 percent of nitrogen from waste water. The nutrients are converted into 5.28.0+10% prills and sold in one-ton tote bags.
Ostara’s patented Pearl process uses a naturally occurring chemical reaction to convert nutrients into hard fertilizer pellets called Crystal Green.
The company has five operational Crystal Green facilities in the United States and one in Europe. Its first Canadian plant recently went into operation processing waste water at Portage la Prairie, Man.
More than half the 15 million litres of waste water that are treated daily at this site originates from local food processors such as Simplot and McCain. It contains high levels of phosphorus and nitrogen.
Portage is studying the Ostara Pearl system as one option for treating its nutrient-laden waste water. The pilot program is significant because waste water from the facility runs into the massive Lake Winnipeg watershed, which has been in the spotlight for the past two decades because high phosphorus levels are damaging aquatic systems.
The Crystal Green system has the potential to recover 100 tonnes of phosphorus a year, according to Ostara president Phillip Abrary.
“It provides a proven and affordable means of helping cities become better stewards of their environment through sound nutrient management practices,” he said
Abrary said Portage is also evaluating technology to remove ammonia from its waste-water streams, marking the first time the Pearl process has been deployed in conjunction with an ammonia removal process.
Veolia uses its ANITA Mox technology to remove more than 80 percent of the ammonia in waste-water treatment plants. The system combines an aerobic and an anoxic process into one reactor with both conventional nitrite producing bacteria and a specific Anammox biomass.
The Ostara Pearl system has been applied only to municipal waste treatment plants, but Abrary said the same technology works just as well with livestock manure.
“As long as an organic waste or manure can be pre-processed into a liquid form, our system can remove over 80 percent phosphorus and 25 percent of the nitrogen,” said Abrary.
“Physically, the way you do that is simply put the manure into a bio-digester to capture the bio-gas. There’s nothing new about that, and there are numerous ways to turn bio-gas into energy.
“What’s left in the bio-digester is liquid containing phosphorus because it does not evaporate. It remains in the liquid until we run it through our Pearl system. That’s why our technology is a good complement to any operation using a bio-digester. It creates one more source of income.”
Abrary said the more a livestock operation expands, the more sense it makes to install the Pearl. Larger operations have a bigger concentration of manure so their distribution radius becomes even more restrictive, whether they move manure by tanker or drag hose.
It becomes even more important to deal with phosphorus transportation when the economic ring of one livestock producer overlaps that of another.
He said the Pearl process relies on natural chemical reactions that take place when magnesium is added to waste organic liquid. Phosphorus molecules and some nitrogen molecules attach themselves to the magnesium.
These tiny particles continue to grow, layer by layer, as long as the liquid circulates or new waste water is added. The process is best compared to the creation of a pearl inside an oyster.
Chemists call the compound “struvite,” and it’s the worst enemy of engineers who manage waste-water treatment plants. There, the mineral struvite forms a concrete-like crust on pumps, valves, pipes and other components in the plants. It’s the cause of high maintenance costs in many plants.
“Researchers at UBC (University of British Columbia) were looking for a way to dissolve or eliminate this struvite,” he said.
They came up with the idea of using magnesium to draw the phosphorus out of the liquid. That was really the main purpose of their research.”
Abrary said the fluid bed is the key to Ostara’s adaptation of UBC’s technology.
It is a large vertical funnel-shaped cylindrical tank, really more like three cylinders stacked on top of one another with the smallest at the bottom and the biggest at the top.
Waste water is pumped in and circulated, along with a measured amount of magnesium.
The presence of magnesium forces the phosphorus and ammonia to crystallize into small pellets that float to the top chamber where the water is calmer.
The prills remain suspended in the liquid as long as they remain small and light weight. Eventually they become heavy enough to sink to the bottom of the fluid bed, from where they are collected, dried and bagged.
“When you cut a prill open, you can actually see the layers or the growth rings like you’d see in a tree. What we have at this point is an extremely pure crystallized product,” he said.
“A granule ranges in size from one millimetre to 3.5 mm and is 99.9 percent pure. We control the exact size by manipulating the fluid bed. The product is not water soluble, so you can apply it to water-logged soil and it will not start to release.
“Crystal Green is plant-activated when organic acids given off by the crop roots contact the granules. It only releases when a root system needs the nutrients. That means lower application rates and much less risk of loss from leaching and runoff.”
Abrary said phosphorus bonding to magnesium gives Crystal Green that extra 10 percent on the chemical expression.
The product is a highly stable, hard crystal that’s dust-free and easy to ship, he added.
“One thing we’ve seen is that Crystal Green is very consistent, regardless of what waste-water source we run through the system,” he said.
“It always comes out precisely as 5.28.0+10%.”
Ostara sells the fertilizer in one ton bags, by the truckload, mainly to vegetable and turf customers. The price is two to three times higher than conventional phosphorus products, but Abrary said the number is deceiving because it’s totally plant available. It’s never tied up in the soil, so farmers apply fewer units.
“We know the turf and vegetable people see the economic benefit. Our next step is to test Crystal Green in broad acre crops like corn, winter wheat and barley. So right now, we have field trials taking place with those kinds of crops.”
Prairie farmers have joked about putting down 100 pounds per acre of phosphorus when they’re 30 years old but not living long enough to see it taken up by their crops.
“Instead, he has to keep applying more phosphorus every year if he expects to grow a crop. Not so with Crystal Green. You put down 100 lb. and it’s taken up by your crop.”
For more information, contact Phillip Abrary at 604-506-2855 or visit www.crystalgreen.com.