Waste disposal, general discussion

In general, calculation of the risk or dose from waste disposal in the numerator of the risk index in Equation 6.2 or 6.3 involves the risk assessment process discussed in Section 3.1.5.1. As summarized in Section 6.1.3, NCRP recommends that generic scenarios for exposure of hypothetical inadvertent intruders at waste disposal sites should be used in calculating risk or dose for purposes of waste classification. Implementation of models describing exposure scenarios for inadvertent intruders at waste disposal sites and their associated exposure pathways generally results in estimates of risk or dose per unit concentration of hazardous substances in waste. These results then are combined with the assumptions about allowable risk discussed in the previous section to obtain limits on concentrations of hazardous substances in exempt or low-hazard waste. 

I will now give an overview discussion identifying the general information needs and the specific decisions called for at each step. I will use as the example case, evaluating a hazardous waste disposal site. Also, I will discuss the application of the process to an actual site being evaluated in California. 

When active or potential polluted zones are located, they are generally contained as quickly as possible by the methods discussed in this chapter. This provides some time for treatment or removal of the contaminants. Environmental pollution of any kind is, of course, the province of EPA. That agency has published a wealth of information pertaining to the problems of waste disposal, containment and treatment. Some of these documents are listed in the References to this chapter. 

This article was written prior to the newly restrictive rules on incinerators used for medical and infectious wastes. However, the information is still valid and useful for the selection and management of incinerators in general for waste disposal of other types. A discussion of the regulatory requirements for incinerators used for hospital and infectious wastes is given in the section immediately following this article. 

There are many other features of the general topic of waste disposal that needn t concern you as a student but are very important in the chemical industry for both manufacturing and research facilities. AU of these factors will be discussed more in Section 8.3.4, which is designed to be read by advanced students as they are preparing to leave college. 

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