Science
By JOHN W. AHLEN

Dilemma of hazardous waste: land disposal

This is the third and final column in a series on hazardous wastes. The previous columns in the series appeared in the December and February "Science" columns.

WHAT should we do with society's hazardous waste? This is a question that is being studied by a special Illinois Hazardous Waste Task Force chaired by Senate President Philip J. Rock and Atty. Gen. Neil F. Hartigan. House Speaker Michael J. Madigan has also appointed a group of House Democratic members to address the subject.

The fate of hazardous waste has traditionally been land disposal, burning and discharge into surface waters. Enthusiasm for a clean environment and the development of antipollution technology to clean up the air and water shifted much of the environmental burden of hazardous waste disposal to land. But environmental crises, such as at Love Canal in New York, have now brought land disposal techniques under close scrutiny. We hear that all landfills leak. We hear that there are alternatives to burying hazardous waste in the ground. And we hear, loud and clear, people saying that they don't want hazardous waste facilities in their communities. But we also know that even after waste volume has been reduced, and the reusable materials have been reclaimed for reuse and the hazard has been reduced by chemical treatment, there is still a residue that must be disposed of. This ultimate disposal is invariably land-oriented. The politico-technical conflict is that some land disposal is necessary, but people don't want such facilities in their communities.

Land disposal methods

There are essentially five options for land disposal of hazardous waste: landfarms, deep wells, surface impoundments, deep burial in mines and shallow burial in landfills.

Landfarming involves treatment and disposal of hazardous wastes that are biodegradable, such as certain liquids, sludges and slurries. When the waste is worked into the soil, microorganisms and chemical reactions decompose the hazardous components of the waste into nonhazardous by-products. The application rates in landfarming must be carefully controlled so that the capacity of the land is not exceeded.

Deep well injection involves pumping liquid hazardous wastes into porous geological formations through oil welllike pipes. The liquid wastes must not be high in suspended solids or too viscous, and they must be chemically compatible with the geological formation into which they are being injected. Pesticide-contaminated process water is an example of the kind of liquid waste which is injected into deep wells. It is important that the geological formations into which liquid wastes are injected are well below the deepest usable ground water resources. The major problem with deep well injection seems to be the uncertainty associated with the movement and fate of potent chemicals injected into the well. Two complaints which probably do not have standing in well-run state-of-the-art operations involve overpressurizing the well, with a possible surface blowout resulting, and the possibility that the liquid waste might lubricate geologic faults in the earth's crust, perhaps resulting in an earthquake. Another concern is that the injected hazardous wastes may contaminate deep deposits of natural resources.

Surface impoundments are natural or man-made pits, ponds or lagoons which theoretically can be used for the storage, treatment or disposal of hazardous waste. The kinds of waste suitable for disposal in surface impoundments are liquids and sludges from a variety of paper, petroleum and chemical industries. The problem with this method of disposal is that most surface impoundments are unlined, and the liquid wastes can percolate through the soil and possibly contaminate ground water. Some feel that surface impoundments are the leading cause of toxic contamination of ground water and point out that nearly one-third of the federal Superfund sites in the U.S. involve leaking surface impoundments.

Most attention is focused on the burial of hazardous wastes. One relatively new but untried technique for land disposal is deep burial in mines. The wastes are theoretically recoverable, but it is not expected that they would ever again be brought to the earth's surface. Such a disposal method is significant because it isolates the wastt from society indefinitely.

Landfilling in relatively shallow trenches is the more common burial technique. Virtually all wastes, regardless of whether or not they should be, can be buried in such trenches. The problem with landfills is that they eventually leak (geologists prefer to say that there is leachate movement) no matter how technologically sophisticated the construction. Landfills leak because either liquid wastes are placed in them or precipitation leaks into the landfill through the protective cover placed over a filled landfill. There seems to be nearly universal agreement that liquid wastes (in bulk or containerized) should not be disposed of in landfills and that improvements in disposal practices and cover design minimize the amount of precipitation that can get into the landfill.

Problems of land disposal

A common problem associated will all forms of land disposal is inadequate ground water monitoring. Such monitoring would serve as an early warning for hazardous waste contamination of local ground water. In 1983, the U.S General Accounting Office issued an

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interim report revealing that 87 percent of the 38 facilities subject to ground water monitoring requirements in Illinois were not in compliance.

Many of the problems with land disposal being faced now are the result of past practices which were driven by economics. Land disposal was cheaper than alternative methods because burial technologies were relatively inexpensive and involved few, if any, environmental safeguards. With the enactment of the Resource Conservation and Recovery Act (RCRA) and the regulations adopted pursuant to it, the costs of land disposal are destined to increase sharply.

RCRA regulations for landfills include requirements for, among other things, a clay or flexible membrane liner to retard leachate movement; a leachate collection system to capture leachate in the landfill and bring it to the surface for treatment and disposal; and a ground water monitoring system to detect any leachate that may migrate from the landfill into local ground water supplies. RCRA also imposes insurance liability for sudden and non-sudden accidental occurences involving disposed hazardous wastes. The effects of the RCRA requirements are beginning to be seen. The costs of land disposal are rising and the off-site disposal industry — which accepts hazardous waste generated by others and disposes of it for a fee — predicts higher costs in the future. The Illinois Environmental Protection Agency (IEPA) has information showing that for some wastes there is a shift occurring away from land disposal toward alternative treatment technologies. For example, between 1980 and 1583 for wastes disposed off-site, the percentage of wastes being land-filled dropped from more than 81 percent to less than 43 percent, the percentage incinerated increased from about 0.5 percent to almost 6 percent, the percentage treated rose from almost 3 percent to over 30 percent, and the percentage recycled went from 15 percent to almost 21 percent.

Perhaps the most significant issue surrounding land disposal of hazardous waste is siting. It is probably the single most important factor in landfill design. As long as the possibility of leachate movement exists, hazardous waste landfills should be located in areas where there is no usable ground water to be contaminated. Finding these sites requires comprehensive site investigations by geologists, and these findings must be incorporated into the engineering design of the landfill. In addition to the protection afforded by the engineering design, there are some indications from current research that natural protective features — such as the characteristics of water moving along the boundary between gravel and fine grained clay — can be used to construct a long-term landfill with very low rates of leachate movement. Some believe that landfills using these natural protective features could last forever.

Siting might also be the land disposal issue of most immediate concern. The Hazardous Waste Task Force's Committee on Land Disposal found that hazardous waste disposal facilities existing now have permits issued before the nation's attention was focused on Love Canal and that it is just about impossible to license a facility today. It was found by the task force's Committee on Alternative Technologies that Illinois' existing hazardous waste landfill capacity will be exhausted within eight years.

In 1982, there were 17 sites in Illinois using land disposal methods for hazardous wastes, according to IEPA data. Except for five off-site landfills, the disposal sites were located on the property where the wastes were being generated. These include seven landfills, seven deep wells (at five sites), three landfarms and two surface impoundments. The actual number of hazardous waste surface impoundments in Illinois is unknown. The two on the IEPA list are impoundments which the owners intend to close as if they were hazardous waste landfills, but there may be as many as 150 of the impoundments, according to an Illinois Legislative Investigating Commission report, that are not on the IEPA list.

Before the problem of what we do with our hazardous waste is solved, the public must regain its confidence in disposal technologies and in the ability of government to protect them from exposure to hazardous waste. □

John W. Ahlen is assistant director of science and technology, Illinois Legislative Council.

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