Goodyear Tire & Rubber Co. scientists reported yesterday they have found a safe, cheap way to dispose of polychlorinated biphenyls (PCBs), one of the nation's most pervasive toxic chemical wastes.
Through a simple chemical reaction, PCBs can be turned into a harmless sludge and common table salt, they said.
"The potential is tremendous if it works," said William Gunter, chief of Environmental Protection Agency's PCB regulation team. The chemical reaction has been successfully demonstrated in Goodyear's laboratories, the company says. EPA has not yet determined whether it will work equally well in a large-scale industrial process, Gunter said, although Goodyear says it can prove that, too.
"Goodyear's technique promises to reduce dramatically the risk, time and financial investment required to safely dispose of PCBs," said Carl E. Snyder, vice president of research at Goodyear.
Of particular importance is whether the Goodyear process can be used to dispose of the estimated 2 million gallons of highly concentrated PCB liquids in the hands of electric utility and industrial companies. These particularly hazardous wastes must be burned in special, high-temperature incinerators, EPA has ruled. The first two such installations, the agency hopes, will be in operation next year.
Snyder noted that attempts to establish incinerators or landfills for PCB disposal usually have stirred up strong opposition.The Goodyear process overcomes that obstacle, he said.
PCB, a clear, oily liquid, found hundreds of uses following its introduction in industry about 50 years ago. Because of its very high burning temperature and chemical stability, it was ideal as an insulator in electrical transformers, as a hydraulic fluid and a lubricant in metal-cutting operations. It was also used in the manufacture of carbonless reproduction paper.
Not until the mid-1960s was the threat of PCB contamination to human health and wildlife recognized. Like other chlorinated organic compounds, it is poisonous and is believed capable of causing cancer. Small amounts can cause an acne-like condition and eye irritation.
In addition, it is retained by human and animal fat cells, and scientists discovered that relatively small PCB discharges into the Great Lakes had been concentrated in trout and other sport fish, reaching high levels that required restrictions on fishing.
Until its manufacture was banned by Congress in 1976, about 10 million pounds of PCBs were lost into the environment each year through vaporization, spills and leaks, according to EPA estimates.
It durability made the hazard worse -- PCBs do not break down naturally into harmless compounds -- and has proved hard to incinerate and difficult to dispose of safely in landfills. An estimated 750 million pounds of PCBs are still in use and must be safely disposed of.
Goodyear owns 75,000 pounds of heat transfer liquid contaminated by low concentrations of PCBs. Because the liquid, which transfers heat from burners to processing operations at several of its plants, is worth more than $10 a gallon, the company wanted to save the liquid while getting rid of the PCBs.
The answer came from Dane K. Parker, a Goodyear scientist who developed a process for combining PCB-contaminated liquid with another chemical, sodium naphthalide. The sodium strips away the chlorine-forming sodium chloride -- table salt -- and harmless, sludge-like polymer that can be filtered out and burned in conventional incinerators.
Very little PCB remains, said Parker -- only 10 parts per million, well below EPA's minimum limit 50 parts per million.
Unlike the highly concentrated PCBs, wastes with low levels of PCBs can be disposed of in approved landfills or burned in certain utility or industrial boilers, Gunter said. Baltimore Gas & Electric Co. is among the utilities currently burning the low-level PCB wastes, he said.
Goodyear's process permits disposal at room temeprature in existing industrial plant equipment, eliminating the need to transfer the dangerous chemical to disposal site, said the company. The chemical process requires only two to three hours, and the disposal cost is only pennies a pound, Goodyear said.
According to Snyder, the process conceivably could be used in treating other harzardous chemicals related to PCBs such as DDT and other pesticides and herbicides.
Goodyear said it has applied for patents on the disposal process. If granted, the patents will be turned over to the public at no cost, a spokesman said.