RE-THINKING PAPER PRODUCTION
WITH HEMP PRODUCTS
Technological advances in the late 19th century made it cheaper to use wood instead of rags for pulp and paper production. Despite renewed interest in hemp during WW I, cultivation was banned in 1937 because of hemp's association with marijuana. During WWII this ban was lifted, and the USDA encouraged farmers acrosss the country to grow "Hemp for Victory." In 1940, world hemp production peaked at approximately 832,000 tons per year. However, after WW II, the restrictions were reinstated and global hemp production declined significantly. Approximately 124,000 tons of hemp are currently harvested annually worldwide. The majority is now produced in China and Eastern Europe.In the 1980s, interest in hemp as a viable and sustainable fiber crop began to develop in Western Europe and North America in association with growing concern about the impacts of deforestation and air and water pollution caused by the pulp and paper industry. Hemp has developed a reputation as an ecologically sound, non-wood alternative to wood for paper production. As a result, the market for hemp paper has begun to grow steadily. In 1994, the US imported approximately 2,000 tons of hemp paper.
It is difficult to analyze the economic costs and environmental impacts of hemp paper production because the fiber is frequently processed with antiquated technology. Outdated mill technology can only convert 50 percent of the stalk into pulp and the scale of production is small (an average of 5,000 tons/year compared with modern wood pulp mills' 250,000 tons/year). As a result of these economies of scale, hemp pulp and paper is expensive. These antiquated mills tend not to have chemical recovery systems, releasing effluents directly into local environments.
However, recent laboratory research and new pulping processes (now at the demonstration level) have shown that hemp can be pulped more productively, cheaply, and with fewer negative environmental impacts than trees. When modern pulping processes and mill technologies are used, fewer chemicals and less energy are required to pulp hemp fibers. In addition, up to 80 percent of unprocessed hemp can be converted to pulp (compared with an average of 43 percent of wood fibers), and mill effluent is significantly cleaner. Furthermore, toxic chlorine bleaching processes can be replaced with environmentally benign processes that use oxygen, hydrogen peroxide, or ozone.
The greatest barrier to hemp paper production in the US today is the ban on legal cultivation. Industrial hemp is grown from certified seed varieties, guaranteed to produce low amounts of THC (0.05-1%, as opposed to 3-15% in marijuana. In 1937, when hemp cultivation was banned, the chemical THC had not been identified.) In the past few years, several countries, including England, Canada, Germany and Australia, have relaxed restrictions, joining more than 20 countries that allow hemp cultivation. There are also efforts in several states (KY, CO, VT, HI, MO, SD, IA) to allow hemp research. These factors could positively influence the future of industrial hemp cultivation in the US. As new advances in farming, processing, and pulping move from experimental to commercial applications, hemp's potential to become a major pulp feedstock for paper production may finally be realized.
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