Turning to New Technologies

By Peter Stoler.

As U.S. industries face the growing problem of how to deal with toxic wastes, which now total an awesome 300 million tons generated each year, they have increasingly turned to new technologies. Science has yet to find foolproof ways of getting rid of all polysyllabic perils. But it has come up with a number of alternatives to simple dumping.

Toxins like organic solvents, PCBs and dioxin will be broken down ^ completely only when burned at temperatures exceeding 2,400 degrees F. Some conventional incinerators can generate such heat, but without careful controls to maintain high temperatures they may spew toxic gases into the air. People fear the fumes may prove as perilous as the chemicals from which they come. But new technologies may overcome these obstacles.

At Times Beach, Mo., J.M. Huber Corp. has used a mobile electric reactor that heats up to 4,000 degrees F to destroy the dioxin in several hundred pounds of soil. Also tested at Times Beach is the EPA's mobile incinerator. It got rid of 99.9% of the dioxin in 1,750 gal. of liquid waste and 40 tons of soil in six weeks. Another movable unit is Westinghouse Electric's plasma arc furnace, which is housed in a 46-ft. trailer. The furnace reaches temperatures of 20,000 degrees F.

Recycling systems also show promise. Companies in California, for example, found that "pickling acid," which is needed in metal-processing plants to remove scale, could be mixed with zinc sulfate and used as a soil additive in citrus orchards, or mixed with air-filtered dust from scrap-steel plants to permit profitable recovery of zinc-iron compounds. Others have found that spent fluid from the manufacture of semiconductors could be used to refine old crankcase oil, helping to eliminate two disposal problems for the price of one.

Perhaps the most innovative technology involves the use of bacteria. A small Texas company called Detox Industries has developed microbes that eat PCBs, creosote and pentachlorophenol. Microbiologist Ananda Chakrabarty of the University of Illinois in Chicago has used a patented "molecular breeding" process to achieve the evolution of a bug that can convert the chief ingredient of the herbicide Agent Orange, 2,4,5-T, into carbon dioxide and chloride. In laboratory tests, his bacteria are so dependent upon the chemical that once they have consumed whatever is available they die.

Perhaps no one, however, seems to have employed bacterial conversion better than Microbiologist James Whitlock of the Homestake Mining Co. He found a solution to the problems caused when the company dumped water laced with cyanide, which is used to leach gold out of ore, into South Dakota's Whitewood Creek. Whitlock examined waste-water samples until he found bacteria, grew them in the lab, then exposed them to higher and higher levels of cyanide and saved the survivors. He then installed these superbugs in a brand new $10 million water-treatment plant, putting billions of them on each of the 48 rotating disks that make up the plant's main processing unit. Because the bacteria possess a sticky body surface, they pick up zinc, iron and other metals in the water as it passes over the plates. They also eat the cyanide that once threatened to kill the waterway's marine life. Barely a year ago, the creek was too toxic for trout, but now they seem to be thriving.

With reporting by J. Madeleine Nash/Chicago