1. Introduction
In this decade, much public and scientific concern has been expressed about the presence of polychlorinated biphenyls (PCBs) in our environment and in our food. Usually the major concern is the long-term cumulative effects of exposure to PCBs on human health and on many forms of life on earth, and not the immediate lethal or overt effects associated with short-term exposure. Based on these scientific warnings, regulators in both Canada and the United States enacted legislation to regulate PCBs. In 1977, PCB production was banned in both countries and strict controls were implemented. As a result of these measures PCBs and PCB wastes, instead of accumulating in the environment, began to accumulate in various forms of temporary containment awaiting destruction.
The purpose of the following technical review is to show that numerous methods of treatment/destruction of PCB wastes, in various forms of development are available in Canada and the United States.
2. Sources of Information
A literature search was performed initially by M.M. Dillon Ltd. but was found to be relatively unfruitful, since the type of technological development for PCB destruction is usually a mixture of:
- application of conventional technology involving a key innovation that is kept secret;
- conceptual studies that are the subject of interim reports between developers and funding agencies; and
- integrated business ventures with a vested interest in maintaining a competitive advantage through non-disclosure.
In short the potential for high profits for companies that gain approval to destroy PCBs has attracted many individuals who are promoting their processes without the type of objectivity that one expects in referred literature. As a result very little useful data showed up in the usual technical literature. The more valuable sources of information were publications such as: Hazardous Materials Intelligence Report, and Eco/log Week.
Another major source was the United States Environmental Protection Agency (EPA) since their highly structured permitting process for PCB destruction is reviewed region by region (EPA regions I through X) on a bi-monthly basis. Each technology seeking EPA approval is listed along with current status and a local regional person to contact for additional information.
Through this EPA listing and personal knowledge of the field the various organizations were contacted by Dillon and information was requested. Once agreement to participate in the study was secured, a confirming letter was sent along with a copy of the terms of reference for the study. The contacts were encouraged to review the requirements of the terms of reference and respond as they saw fit.
Three major studies performed in the United States supplemented the list of contacts. These were: EPRI, 1979; Ackerman et al., 1981; and Sworzyn and Ackerman, 1981.
These reports, while useful in ensuring coverage of the field up to 1980, had a drawback in that they selectively suggested potential applications of known, off-the-shelf units. Upon checking, in several instances, the technology had not been applied to PCB destruction.
Data received from companies was uneven. Some provided comprehensive data and that is reflected in the detail of their write-up. Others provided sketchy information or were at such an early stage of development that the process description has been included in a brief overview manner.
Costing data was arrived at independently of company pricing suggestions and was current in February 1982. For the purpose of this study it was important that comparable capital and operating costs be put forward. Costs provided by promoters of a technology often included a local advantage that would not always apply to an individual contemplating the use of that technology at his own location. This does not mean that similar advantage might not be realized in Canada, but a comparison could not be made on any basis other than an independent assessment.
Care must be exercised in using the costing data. The PCB feed rate used in arriving at costing data could consume an individual's PCB waste stockpile in a relatively short period of time. Consideration must, therefore, be given to under utilizing a process or scaling it down and losing the economy of its scale. For costing purposes PCB liquid waste was assumed to be 20% PCB in oil and solid waste was assumed to contain 10% PCB |
