PCB-destroying process named one of 1992's top new technologies
September 24, 1992
RICHLAND, Wash. –
A new process that inexpensively destroys PCBs, pesticides and other hazardous organic materials has been selected as one of the top 100 technological developments of 1992 by Research and Development Magazine. The base-catalyzed destruction process was developed jointly by researchers at the U.S. Department of Energy's Pacific Northwest Laboratory, Battelle Memorial Institute, the U.S. Environmental Protection Agency's Risk Reduction Engineering Laboratory and the Naval Civil Engineering Laboratory. Battelle operates PNL for DOE.
The magazine conducts the annual R&D 100 Award competition to honor the most promising new products, processes, materials or software developed throughout the world. Awards are based on a product's technical significance, uniqueness and usefulness. This is the 30th year of the competition.
Base-catalyzed destruction is a portable process that detoxifies contaminated soil on site at a rate of .9 metric ton (one short ton) per hour. The system accepts a steady intake of excavated soil that is then mixed with a base chemical -- sodium bicarbonate -- which acts as a catalyst. Next, the soil is fed into a reactor where heat is applied, converting contaminants into non-hazardous compounds. The treated soil is cooled and is suitable for backfill.
The BCD process offers many advantages over existing chemical dechlorination methods, including the potential for significant cost savings. The operating costs of a full-scale BCD system are projected to be less than one-fourth the operating costs of incineration -- currently the most common destruction process.
The incineration process requires expensive, high-temperature burners and typically generates trace amounts of cancer-causing dioxins. Other chemical dechlorination methods often require the use of expensive, hazardous chemicals. In comparison, the BCD process operates at a much lower temperature, uses small amounts of inexpensive, nonhazardous chemicals that can remain in the treated soil and produces a very limited off-gas stream. In addition, the BCD process is completely transportable and saves large capital investment costs by using a configuration of "off-the-shelf" materials.
Prior to the late 1970s, PCBs (polychlorinated biphenyls) were a primary component of organic liquids, such as lubricants and heat transfer oils, used for various industrial purposes. However, PCBs, partially due to their thermal and chemical stability, do not break down naturally in the environment.
Chlorinated contaminants have been linked with liver damage and other serious health problems. Although the debate continues on the health effects of PCBs, Congress mandated the phaseout of chemicals containing PCBs in 1979. To date, an estimated 900 million metric tons (one billion short tons) of soil contaminated with PCBs and other chlorinated contaminants have been identified and must be treated to meet current EPA regulations.
In addition to applications on PCBs and pesticides, the BCD technology may be used to detoxify a variety of other chlorinated contaminants, including solvents, dioxins and many wood preservatives.
The process technology was invented by researchers at EPA with development funding provided by the Navy. The demonstration system was designed, built and applied by researchers at PNL and Battelle-Columbus. PNL developers include Michael D. Brown, Harley D. Freeman and Andrew J. Schmidt.
A PNL team will be demonstrating the PCB-destroying technology this winter at a contaminated Navy site in Guam.