<P> In modern cotton production, cotton arrives at industrial cotton gins either in trailers, in compressed rectangular "modules" weighing up to 10 metric tons each or in polyethylene wrapped round modules similar to a bale of hay produced during the picking process by the most recent generation of cotton pickers . Cotton arriving at the gin is sucked in via a pipe, approximately 16 inches (41 cm) in diameter, that is swung over the cotton . This pipe is usually manually operated, but is increasingly automated in modern cotton plants . The need for trailers to haul the product to the gin has been drastically reduced since the introduction of modules . If the cotton is shipped in modules, the module feeder breaks the modules apart using spiked rollers and extracts the largest pieces of foreign material from the cotton . The module feeder's loose cotton is then sucked into the same starting point as the trailer cotton . </P> <P> The cotton then enters a dryer, which removes excess moisture. The cylinder cleaner uses six or seven rotating, spiked cylinders to break up large clumps of cotton . Finer foreign material, such as soil and leaves, passes through rods or screens for removal . The stick machine uses centrifugal force to remove larger foreign matter, such as sticks and burrs, while the cotton is held by rapidly rotating saw cylinders . </P> <P> The gin stand uses the teeth of rotating saws to pull the cotton through a series of "ginning ribs", which pull the fibers from the seeds which are too large to pass through the ribs . The cleaned seed is then removed from the gin via an auger conveyor system . The seed is reused for planting or is sent to an oil mill to be further processed into cottonseed oil and cottonseed meal . The lint cleaners again use saws and grid bars, this time to separate immature seeds and any remaining foreign matter from the fibers . The bale press then compresses the cotton into bales for storage and shipping . Modern gins can process up to 15 tonnes (33,000 lb) of cotton per hour . </P> <P> Modern cotton gins create a substantial amount of cotton gin residue (CGR) consisting of sticks, leaves, dirt, immature bolls, and cottonseed . Research is currently under way to investigate the use of this waste in producing ethanol . Due to fluctuations in the chemical composition in processing, there is difficulty in creating a consistent ethanol process, but there is potential to further maximize the utilization of waste in the cotton production . </P>

As a result of the introduction of the cottongin