tre) a n d available from the Ministry of Health's Institute of Environmental Health & Forensic Sciences, Ham Research Centre, P.O. Box 29181, Christchurch, N e w Zealand.
TECHNOLOGY
Two technologies have been developed to tackle recycling of rubber products, especially automobile tires. Of the 235 million tires d u m p e d annually in the United States only 1 7 % are recycled or b u r n e d for energy. T h e rest e n d u p in landfills. O p e n d u m p i n g can lead to tire fires, w h i c h produce hazardous combustion products (see Science Currents). Preliminary studies by Japanese researchers indicate that cured rubbers may be easily decomposed in supercritical water to potentially recyclable hydrocarbons. Toshinari T e n n o h (Nishikawa Rubber Co., Hiroshima) and his colleagues claim that rubber treated at temperatures above 400 °C in the presence of > 1 M NaOH will decompose within 15 m i n into an oily substance composed mainly of 20 carbon aliphatic a n d olefinic hydrocarbons. T h e sulfur is converted to H 2 S, w h i c h in t u r n reacts w i t h ZnO in the rubber to form ZnS. No sulfur-containing organics were identified in the decomposition mixture. Meanwhile, ECO 2 , Inc. (Hawthorne, FL), has received state approval to operate a tire pyrolysis reactor. The c o m p a n y shreds tires into " c r u m b rubber," separating out the steel and cotton from the tire. The c r u m b rubber is either sold for other uses or converted via pyrolysis into fuel oil a n d carbon black. Methane is collected from the pyrolysis and used to fuel the reactor. ECO 2 has already signed a contract to sell its a n n u a l output of fuel oil a n d half of its carbon black. The c o m p a n y is building additional pyrolysis reactors in Florida and Ohio.
Researchers from Oak Ridge National Laboratory (Oak Ridge, TN) have patented a simple and inexpensive heat exchange device that increases automobile air conditioner efficiency by 2 0 % . If fully i m p l e m e n t e d i n the United States, the n e w design could save 340 million gal of fuel annually a n d eliminate 6.5 billion lb of C 0 2 emissions. The heat exchanger allows the air conditioner coils to be "overfed" w i t h liquid coolant, t h u s increasing cooling capacity. Excess liquid coolant that exits the evaporator is routed back into the heat exchanger for vaporization, t h u s protecting the compressor a n d reducing its work load. Studies are n o w u n d e r way to apply this technology to stationary air conditioners, heat p u m p s , a n d refrigerators.
A single exhaust system modification could reduce soot and N O x emissions from diesel engines. Atsushi Tsutsumi (University of Tokyo, Japan) a n n o u n c e d at the November meeting of the American Institute of Chemical Engineers that adding a centrifugal fluidized bed removed soot in diesel exhaust and broke d o w n the N O x . Previous proposals for reducing N O x emissions from diesel engines have involved changes in the combustion process, w h i c h sacrifices fuel economy. Tsutsumi's modification to the exhaust system s h o u l d preserve fuel efficiency. In fact, soot collected on the fluidized b e d seems to improve the decomposition of N O x , making the process more efficient. Spurred by the growing efforts to remove chlorine from paper mills, University of Georgia biochemists have developed an enzyme technology to bleach paper. The EnZone process combines an enzyme treatment w i t h oxygen, ozone, a n d alkaline hydrogen peroxide bleaching stages. According to project leader Karl-Erik Eriks-
son, the process fully bleaches kraft p u l p s a n d produces p u l p w i t h physical characteristics similar to those p r o d u c e d by traditional chlorine-based technology. A pilot plant that will test the EnZone process is being built on the University of Georgia c a m p u s in Athens.
BUSINESS The expanding grass-roots movement to legislate a ban on chlorine and chlorine-containing chemicals in manufacturing (see Federal Currents) has p u t i n d u s try on the defensive. Paul Tippett, chair of the Council of Great Lakes Industries, recently labeled "irresponsible" one s u c h proposed b a n in the Great Lakes region that w o u l d affect Canada a n d the United States. Tippett claimed that eliminating chlorinated chemicals w o u l d cost U.S. and Canadian consumers $102 billion a year, w i t h an additional $67 billion n e e d e d for changes in the infrastructure a n d facilities to distribute chlorine substitutes. In the United States, 4 5 % of all industries use chlorine. Complains Tippett, "To make sweeping recomm e n d a t i o n s concerning a product as w i d e l y u s e d as chlorine without trying to u n d e r s t a n d the economic impact defies reason."
Industry experts are predicting that the market for air pollution controls will increase over the next two years by 86%. A market forecast by the Institute of Clean Air Companies (ICAC) found that expanding markets for NO x and volatile organic emissions conEnviron. Sci. Technol., Vol. 28, No. 1, 1994
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