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Cattail Harvester Provides Fuel, Captures Phosphorous
If Canadian researcher Richard Grosshans is right, cattails could be a new wonder crop. What started as a way to filter phosphorous (P) from surface water has evolved into a much bigger deal. He has even designed and built a cattail harvester.
"Phosphorous runoff has been looked at as a pollutant and waste product, but it's actually a valuable resource. If we can harvest plants that absorb it, we can capture energy and recover the P."
Funded by the International Institute for Sustainable Development, Grosshans initially looked for a way to remove the excess P that ends up in surface water and that cattails naturally absorb. Using the cattails for biofuel made sense. Now the researcher is looking at cattail fuel ash, which retains 90 percent of the P, as a fertilizer source.
To test his ideas, Grosshans designed and built a cattail harvester. The harvester is a trailer about 5 ft. long and 5 ft. wide with ATV-type flotation tires. It's towed by an 8-wheel Argo amphibious vehicle. It carries a small, gas engine-powered, hydraulic pump and a heavy-duty, 6-ft. sickle bar mower.
"The trailer is also hydraulic, so we can lower the mower and then adjust the cutting height by raising or lowering the trailer," explains Grosshans. "After trying air boats and other systems, we discovered the best harvesting condition was to be in water a foot or less in depth."
He also discovered that the best cutting height for the plants was about a foot. Cut too low, and the plant would drown.
"We want the stubble to live so the plant will regrow to be harvested again," says Grosshans.
The cut cattail stalks were initially baled for use in a burner designed for square bales. Grosshans switched to pelletizing for a standardized fuel product. The next step is to build a bigger harvester that cuts, gathers and hauls the material out of the wetland.
"It may be like a corn forage harvester with large balloon tires for low impact," he says. "We are also looking at modifying some European machines that harvest reeds for roof thatching.
"We are doing some greenhouse experiments to see how valuable the cattails are as a fertilizer source," says Grosshans. "We hope to have the harvester ready in about a year and a half as we go from pilot scale to commercial scale."
Contact: FARM SHOW Followup, Richard E. Grosshans, International Institute for Sustainable Development, 161 Portage Ave. East, 6th Floor, Winnipeg, Man., Canada R3B 0Y4 (ph 204 958-7718; rgrosshans@iisd.ca; www.iisd.org).

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2011 - Volume #35, Issue #4