Incineration, hazardous wastes problem

J. P. Reynolds, R. R. Dupont, and L. Theodore, Hazardous Waste Incineration Calculations Problems and Software, ]ohn Wiley Sons, Inc., New York, 1991. 

While much of this work has addressed the destruction of pesticides as such, most current activity is concerned with the more general problem of hazardous waste incineration. The following discussion summarizes some of the key studies that have dealt specifically with the incineration of pesticides and pesticide wastes, as well as hazardous waste incineration in general. 

In the mid-1980s, the city of Philadelphia was experiencing a problem common to many urban areas in the United States. The city had run out of places to dispose of some of its solid wastes. One hatch of wastes that posed a special problem consisted of ash produced at the city s Roxhorough incinerator. These wastes contained hazardous chemicals, which made them unacceptable to other "host states, such as Ohio, Virginia, South Carolina, and Georgia, which had been receiving wastes from other urban areas on the East Coast. 

The treatment of hazardous wastes has emerged in the last 10 years or so as one of this country s most acute environmental problems. It is now recognized that the cost of dealing with the accumulated and yet-to-be-gen-erated waste will be staggering. Unfortunately, the hard science underlying waste treatment strategies is woefully inadequate. For example, with respect to hazardous waste incineration, Senkan [45] has noted that... 

Hazardous Waste Incineration Calculations Problems and Software... 

Another problem is the detoxification of the hazardous wastes that are already present in the environment. Efforts are thwarted by the problan of how less toxic are the detoxification products in themselves Thus, in incineration, for instance, what are the toxicides of all the final combustion products Called products of incomplete combustion, or PlCs, these are the myriad by-products and coproducts of the competing reactions that occur during combustion, and for that matter, during any chemical conversion, more or less. Can they ever be fully detected and analyzed Or if selectively scrubbed, what is to be the disposition of the absorbed materials What is called detoxification may be merely a further dispersion throughout the ecosphere, and a process of trading one set of problems for another. 

The committee has concluded that CAIS items can be destroyed safely in hazardous waste incinerators, assuming the arsenic content does not present a site-specific air emission problem (NRC, 1999a). The physical and chemical properties of a chemical govern the ability of incinerators to destroy and remove the hazardous constituents. The hazardous constituents in CWM material share the chemical and physical characteristics of the hazardous constituents in commercial hazardous waste. 

INCINERATION can be adapted to the destruction of a wide variety of hazardous wastes, and, unlike many other methods, is often a permanent solution to the disposal problem. Incineration is not a new technology and has been used for treating organic hazardous waste for many years. The major benefit of incineration is that the process actually destroys most of the waste rather than just disposing of or storing it (Oppelt, 1987). 

Incineration For other than heavy metals and a few other forms of hazardous waste, incineration can be a safe method of disposal. Incineration processes must fit the kind of waste involved. Incinerators can produce heat and steam for other processes. Today incinerators must have scmbbers downstream of the combustion process to ensure that hazardous materials do not escape. Researchers continue to study combustion methods and methods for recovering any dangerous gases or particulates remaining from combustion. A major problem for incinerators is public acceptance. Few are under construction. People in communities that are potential sites for hazardous waste incineration plants frequently do not want such a facility in their neighborhood. 

Hot ash is often quenehed in water. Prior to disposal it may require dewatering and ehemical stabilization. A major consideration with hazardous-waste incinerators and the types of wastes that are incinerated is the disposal problem posed by the ash, especially with respect to potential leaching of heavy metals. 

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