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Ronald Brown
LSU News Service
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BATON ROUGE -- For every teaspoon of sugar we put in our coffee, another large handful of sugarcane rind and pulp is dumped onto the growing heap outside the sugar refinery.
This coarse, fibrous material is called bagasse, and getting rid of it has always been a problem for sugarcane refiners. In Louisiana, mills produce more than 1.8 million tons of it annually. "Even the mills that use it for their burners use only 95 percent of it. And natural gas is much more efficient," said Billie Collier, director of LSU's School of Human Ecology. That leaves almost 100,000 tons of the stuff to pile up or be hauled away every year.
But Collier and her husband, John, have come up with a solution. They have developed a process for breaking down the rind and turning it into a coarse fabric that can be used for erosion control.
There are a number of textiles already in use as erosion-control mats, said John Collier, a chemical engineer who also works at LSU. But each has certain drawbacks that bagasse does not. And bagasse has one advantage for Louisiana that the others do not: there is plenty of it here to work with.
Collier has built a prototype machine that separates the fibers and deposits them in a form that can either be made into a mat or baled for transportation. The process essentially uses heat and a strong alkaline solution to break down the lignin, which is the glue that holds the fibers together, combined with a mechanical beating to help break the fibers apart.
Erosion-control mats are used on places such as freeway embankments to keep the earth in place until grass grows. "We can combine this with grass seed and hold the soil in place and seed the embankment all at once," John Collier said.
One advantage of the Colliers' process is that it does not completely remove the lignin. The fibers can be baled, shipped, then mixed with water and pumped through a high-pressure hose onto an embankment where they will set up and form a mat within 45 minutes. The lignin, a natural adhesive, holds the fibers together and will not dissolve in a rainstorm.
There is a large market for erosion mats, and several types are available. Some are made with straw, some with wood and some with coconut fibers. The coconut-fiber mats are the most desirable, but they're also the most expensive, said John Collier. Another problem with them, as with the straw mats, is the synthetic thread used to sew them together. The thread does not decompose and is frequently caught up on mower blades after the grass has grown, he said.
"We have tested our mats on a freeway embankment in Baton Rouge and found that they're comparable to commercial products," said Billie Collier. "In fact, in trials some of the commercial products washed away."
One of the commercially available mats uses an adhesive rather than thread to keep the fibers together, but it's an adhesive that has to be added to the mix. The fact that bagasse mats are held together by their own natural adhesive is one reason the Colliers believe their product will be cheaper to manufacture and sell.
Another economic advantage of bagasse is the quantity available. Right now, it costs the mill owners to dispose of the waste. If bagasse becomes a viable raw material, it would become a supplemental source of income for mill owners and may affect the price of sugar or the amount of money mill owners pay to the farmers. "Government sugar supports are being phased out. Anything we can do to help the farmers is good," said Billie Collier.
Biodegradable erosion mats aren't the only thing sugarcane fiber is good for. The Colliers are looking into making industrial-grade fabrics that can take the place of burlap, be used as batting or even replace fiberglass in some instances.
They are also investigating the possibility of getting cellulose from the fibers. Cellulose is the material from which rayon and a fiber with the trade name of TencelÆ is made.
The process has been patented, and the Colliers are looking for financial backers for CaneTech International, the company they have created to manufacture and market the product.
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