In Business, Creating Sustainable Enterprises & Communities

THE“WASTE” WITH 2.5 MILLION TONS OF POTENTIAL

In Business, January/February, 2004, Vol. 26, No. 1, p. 26

Cotton gin waste is on the verge of something big, say analysts, who see markets in erosion control, livestock feed and fiberboard.

Al Fava

EACH YEAR, the U.S. cotton industry harvests 17 to 18 million bales that go through the ginning process to separate the lint and seed from cotton by-products commonly referred to as “trash,” “waste” or “biomass.” U.S. cotton gins annually produce more than 2.5 million tons of gin waste.
Farmers and their gins sell the lint and seed on an open market, but the gin waste can be a burden on the industry. Some gins dispose of a portion of their waste by offering it free to local homeowners for mulch or fertilizer. Some farmers spread it across their fields as organic fertilizer, but it can be full of weed seeds. Some gins compost their biomass, but most have a difficult time recovering costs of composting. The vast majority of U.S. cotton gins pay for the disposal of gin trash to a tune of $4 million to $6 million a year.
“Next to dust emissions and air quality issues, what to do with gin waste is one of the top issues facing the ginning industry,” says Greg Holt, an agricultural engineer with the USDA-Agricultural Research Service (USDA-ARS) Cotton Production and Processing Research Unit in Lubbock, Texas.
The by-products generated by the cotton ginning process are referred to as gin trash or gin waste primarily because of the costs associated with their disposal and their limited value in current utilization applications, Holt says. By-products created can consist of cotton bur, bark, leaf matter, twigs, crushed seed, small amounts of lint, and even grass and weed seeds - a very fibrous composite of materials.
Limited application for raw gin waste has been found in feeding the material to livestock as a form of roughage. This low-value use is usually not cost-effective because of the expenses of transportation and handling considerations. Through a cooperative research agreement with Cotton Incorporated (www.cottoninc.com), USDA-ARS researchers and private cooperators are on the verge of developing alternative uses for gin biomass.
ONE IDEA SPAWNS ANOTHER
Several years ago, an agricultural engineer at the USDA-ARS Lubbock research unit was working on a project with Cotton Incorporated called EasiFlo cottonseed, in which cottonseed was starch-coated to make it flow better through the storage bins and truck feed handling systems used in the dairy industry. At the same time, Holt was beginning his work on finding viable uses for cotton by-products. The two engineers talked and decided to run gin waste through the same processes that were used to create EasiFlo cottonseed.
“Most ginners would like to dispose of the cotton by-products by selling them to someone. But without adding value, finding any kind of prolonged commercial use for this biomass in the United States has been difficult,” says Holt. “So we thought that if we could add value to gin waste, we could turn a financial liability into a financial asset that enhances both the farmers' and ginners' revenue stream.”
Holt organized the loan of an extruder from Insta-Pro International in Des Moines, Iowa. A gelatinized cornstarch is sprayed on the gin waste before it is run through the extruder. In the extrusion process, material is compressed and ground, cooked at 220° to 240°F and exposed to high and low atmospheres of pressure. When it goes through the extruder, cell walls rupture killing any seeds and fungus spores that the gin waste may harbor.
The finished product is a sterile, fibrous material that has been named COBY™ (for cotton by-product). The process of making COBY has been patented by USDA and licensed to Insta-Pro International. COBY is being tested as livestock feed and as pelletized fuel for residential pellet stoves, says Holt. There is promise in a third area where COBY is used as a hydromulch or landscaping mulch for erosion control or weed suppression. COBY's potential for being used as a hydromulch has caught the eye of Ed Lee.
HYDROMULCH FOR EROSION CONTROL
Owner and president of Summit Seeds Incorporated in Manteno, Illinois, Ed Lee was in Lubbock to look at buying machinery manufactured by a cotton gin equipment company. While in Lubbock, Lee was given a tour of the local cotton industry, which included a visit to the USDA-ARS research unit. There he discovered Holt and his COBY project.
Lee, ever the entrepreneurial thinker, instantly saw potential in the product and became a private cooperator on the project to turn COBY into a hydromulch. “I took some samples from Greg, obtained funding from a USDA-SBIR Phase I Product Development Grant, and began the initial phase of the hydromulch study,” recalls Lee.
Two separate studies were conducted to assess how well the COBY product would perform as a dry-applied bedding mulch and as a hydromulch. The bedding mulch study was conducted at Summit Seed's Manteno, Illinois facility and involved 31 separate treatments, ten mulches at three application rates and a control plot which had no mulch added. Each treatment (mulch and application rate) was applied to plots that were five feet by five feet. The treatments were replicated three times and evaluated for eight weeks. For each plot, the following information was recorded: 1) Coverage Factor (C-factor); 2) Number of weeds; 3) Soil temperature; 4) Soil moisture; and 5) Plant robustness/health.
In a separate study, three different COBY products were evaluated for use as a hydro-mulch and compared to traditional wood and paper mulches commonly used for this application. Seven mulches at two application rates were used in the study with each treatment replicated three times. Each run consisted of loading a set amount of a sandy clay loam into two feet by ten feet erosion trays, elevating the trays to a nine percent slope and placing them in the rain simulator. The rain event was to simulate a rain equivalent to 2.5 inches per hour.
“It's important to understand that once the gin by-products are run through the extrusion process, you do not have a finished product,” says Lee. “We merely have potential for a product.”
The leading hydromulch products are made from wood and paper. Because it is so fibrous, COBY adheres to the ground well. When tested against the leading mulch products, COBY as a hydromulch has demonstrated equal or better soil erosion control - an important step toward becoming a true marketable product, according to Lee.
“We are not, however, getting the visual ground coverage that you get with wood or paper hydromulches,” he adds. “Poor coverage can lead to poorer seeding rate if you are using the hydromulch as a seed carrier.” More importantly, the mulching industry is very visually-driven and a hydromulch that looks like it gives less ground coverage than wood or paper products is doomed from the start, says Lee. “No matter how much we talk about its ability to control soil erosion, if the coverage is not there, people may reject it because of what they see on the ground.”
THE REFINING OF COBY
Color dyes are being tested on COBY to improve its visual aesthetics. Higher rates of the hydromulch are also being studied as a way of improving its ground coverage look, but higher rates can be costly for handlers and consumers. “There are lots of issues that have to be dealt with before this hydromulch made from COBY can become a marketable product,” Lee concludes. “I am optimistic that we will overcome the challenges that stand before us. Otherwise, I would not be spending the time with it that I am.”
But it could be another use for gin waste, which costs cotton gins about $2 per ton in disposal fees. “I think there is huge potential in gin waste beyond erosion control, weed suppression or livestock feeding,” says Tom Wedegaertner, director of Cottonseed Research and Marketing at Cotton Incorporated, which funds the gin biomass research at USDA-ARS.
“We may never fully develop some of the things we are working on, but gin biomass is a resource that is being underutilized,” Wedegaertner adds. “Whether it's for fiber board, composites, landscaping mulch, hydromulch or whatever, I think it is an overlooked, renewable resource, and it feels like we are on the verge of something that will be very important to the U.S. cotton industry.”