Treatment technologies are chemical, biological, or physical processes applied to hazardous waste or contaminated materials to permanently change their condition. This Citizen’s Guide focuses on treatment technologies for soil, sludge, sediment, and debris.
Treatment technologies destroy contaminants or change them so that they are no longer hazardous or, at least, are less hazardous. They may reduce the amount of contaminated material at a site, remove the component of the waste that makes it hazardous, or immobilize the contaminant within the waste.
Innovative treatment technologies are newly invented processes that have been tested and used as treatments for hazardous waste or other contaminated materials, but still lack enough information about their cost and how well they work to predict their performance under a variety of operating conditions.
Why use an innovative technology?
Treatment of contaminated sludges and soils is a field of technology that has developed and grown since Congress passed the 'Superfund' law for contaminated waste site cleanup in 1980. An initial approach to eliminate a hazardous waste from a particular location was to move it somewhere else, or cover it with a cap. These methods use land disposal as the solution to the problem. With an increasing number of cleanups underway, and the passage of amendments to the Superfund law in 1986 that stated a preference for treatment, demand developed for alternatives to land disposal that provided more permanent and less costly solutions for dealing with contaminated materials. Development and use of more suitable treatment technologies has progressed.
As knowledge about the cleanup of contaminated sites increases, new methods for more effective, permanent cleanups will become available. Innovative treatment technologies, which lack a long history of full-scale use, do not have the extensive documentation necessary to make them a standard choice in the engineering/scientific community. However, many innovative technologies have been used successfully at contaminated sites in the United States, Canada, and Europe despite incomplete verification of their utility. Some of the technologies were developed in response to hazardous waste problems and some have been adapted from other industrial uses.
Developing and perfecting treatment technologies is an ongoing process, as shown in Figure 1. The process begins with a concept — an idea of how to treat a particular hazardous waste. The concept usually undergoes a research and evaluation process to prove its feasibility. If the concept is found to be useful, often the next step is to undergo bench-scale testing. During bench-scale testing, a small-scale version of the technology is built and tested in a laboratory. During this testing, it is considered an emerging technology. If it is successful during bench-scale testing, it is then demonstrated at small-scale levels at field sites. If successful at the field demonstrations, the technology often will be used full-scale at contaminated waste sites. As the technology is used and evaluated at different sites, it is continuously improved.
How is a treatment technology selected for a site?
Before a treatment technology can be selected for a Superfund site, detailed information about the site conditions and contaminants must be collected. EPA uses this information to determine which of the possible remedies will be capable of meeting the clean-up standards that EPA has set.
A treatability study is often conducted to assess a treatment technology’s potential for success. It is conducted on contaminated material from the site, either when the treatment technology is being considered or after selection of the remedy, in order to collect additional operation and performance information.
There are three levels of a treatability study. The level chosen depends on the information available about the site and technology and the nature of information that is needed. The quickest, least expensive treatability study is the laboratory screening. It is done to learn more about the characteristics of the waste to determine if it would be treatable by a particular technology. A laboratory screening test takes a matter of days and generally costs from $10,000 to $50,000. Successful laboratory screening may lead to more sophisticated treatability studies.
The next level of a treatability study is the bench-scale study which provides greater information on the performance (and, in some cases, the cost) of a technology by simulating the treatment process using a very small quantity of waste. The objective of this type of test is to determine if the technology can meet the clean-up standards set for the site. These tests typically cost between $50,000 and $250,000.
At the highest level, the pilot-scale treatability study is usually conducted in the field or the laboratory and requires installation of the treatment technology. This study is used to provide performance, cost, and design objectives for the treatment technology. Due to the cost of this type of study—generally more than $250,000—it is used almost exclusively to fine-tune the design of the technology following other treatability studies.
What happens if a technology does not work?
There is always a possibility that a treatment technology, established or innovative, may not work once it is in full-scale operation in spite of the best engineering design. Site conditions that could not be predicted from the smaller-scale studies are often to blame. Natural conditions are far more complex than laboratory conditions.
A technology may be adapted or redesigned to treat targeted waste, despite initial failures. In some rare cases a different technology may have to be designed and installed. Experience with and increasing use of innovative treatment technologies will lead to better and faster ways to clean up the environment.
Where are innovative treatment technologies being selected?
Industry is using technologies labeled as 'innovative' by EPA for containing and treating the hazardous wastes generated during manufacturing processes. Innovative technologies also are being used under many federal and state clean-up programs to treat hazardous wastes that have been improperly released on the land. For example, innovative technologies are being selected to manage contamination (primarily petroleum) at some leaking underground tank sites. They also are being selected to clean up contamination that resulted from past disposal practices at industrial sites regulated under the Resource Conservation and Recovery Act, and to clean up contamination at uncontrolled hazardous wastes sites, known as Superfund sites. One innovative treatment technology, soil vapor extraction, is now routinely used in federal and state clean-up programs. As more cost and performance data are documented, innovative treatment technologies will be increasingly recognized for their effectiveness.
Why is EPA encouraging the use of innovative treatment technologies?
The Environmental Protection Agency is encouraging the selection of innovative treatment technologies for site remedies because they have the potential to be more cost-effective and to provide better and more efficient cleanups. In addition, they are often more acceptable to surrounding communities than established treatment technologies.