Chemical-radioactive Mixed Waste

Multihazardous waste, (a) Chemical-radioactive waste, or mixed waste, (b) chemical-biological waste, (c) radioactive biological waste, and (d) chemical-radioactive biological waste. 

Management of multihazardous waste is complicated further by local or state requirements that may be inconsistent with the relative risk of each hazard and with sound waste management practices. Chemically hazardous waste that contains short-half-life radionuclides may, for example, be best managed by holding the waste in storage for decay, which may require up to 2 years. However, the EPA and state rules usually limit storage of chemically hazardous waste to 90 days. 

Commercial treatment or disposal facilities for multihazardous waste from laboratories are scarce. Many of these waste types are unique to laboratories and are generated in such small volumes that there is little incentive for the development of a commercial market for their management. 

Examples of laboratory mixed waste include the following  

Mixed waste produced at university, hospital, and medical research laboratories is typically a mixture of a low-level radioactive waste and chemically hazardous waste. Mixed waste from nuclear and energy research laboratories can include both low- and high-level (e.g., spent nuclear fuels) radioactive materials combined with chemically hazardous waste. Disposal options for mixed waste are usually very expensive. For many types of mixed waste, there are no management options other than indefinite storage on site, or at an approved facility, in the hope that treatment or disposal options will be created in the near future. 

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The committee recommends that the Environmental Protection Agency encourage safe disposal of chemical-radioactive (mixed) waste materials with short haU-lives by excluding the decay-in-storage period from the current 90-day limitation on storage of hazardous waste. 

Documentation associated with HCF waste management activities and maintained in the HCF Facility includes Chemical Waste Disposal Requests, Radioactive/Mixed Waste Disposal Requests, Radioactive Waste Traveler Forms, Radioactive and Chemical Waste Addition Logs, and storage-facility periodic inspection checklists. The respective waste management group within the ES H Center, as described below, maintains the original disposal requests. 

The physical and health hazards associated with chemicals should be determined before working with them This determination may involve consulting literature references. Laboratory Chemical Safety Summaries (LCSSs), Matmal Safety Data Sheets (MSDSs), or other reference materials (see also Chapter 3, section 3.B) and may require discussions with the laboratory supervisor and consultants such as safety and industrial hygiene officers. Every step of the waste minimization and removal processes should be checked against federal, state, and local regulations. Production of mixed chemical-radioactive-biological waste (see Chapter 7, section 7.C.1.3) should not be considered without discussions with environmental health and safety experts. 

Materials that pose a hazard because of significant radioactivity are outside the scope of this volume, although they may be chemically treated in a manner similar to the nonradioactive materials discussed in this chapter. Their handling and disposal are highly regulated in most countries. Low-level radioactive mixed waste is discussed in section 7.C above. 

Nuclear wastes are classified according to the level of radioactivity. Low level wastes (LLW) from reactors arise primarily from the cooling water, either because of leakage from fuel or activation of impurities by neutron absorption. Most LLW will be disposed of in near-surface faciHties at various locations around the United States. Mixed wastes are those having both a ha2ardous and a radioactive component. Transuranic (TRU) waste containing plutonium comes from chemical processes related to nuclear weapons production. These are to be placed in underground salt deposits in New Mexico (see... 

On July 18, 2000, the Agency released HWIR-waste exemption levels for 36 chemicals that were developed using a risk model known as the Multimedia, Multi-pathway and Multi-receptor Risk Assessment (3MRA) Model.17 The May 16, 2001, HWIR-waste rule revised and retained the hazardous waste mixture and derived-from rules as previously discussed in this module. In addition, the rule finalized provisions that conditionally exempt mixed waste (waste that is both radioactive and hazardous), if the mixed waste meets certain conditions in the rule.5... 

Perma-Fix Environmental Services, Inc. (Perma-Fix), has developed the Perma-Fix Process for the neutralization and stabilization of hazardons, radioactive, and mixed wastes. The Perma-Fix Process is a two-step treatment involving proprietary chemical treatment of wastes followed by the addition of stabilization chemicals to create a final waste form with the hazardous component of the wastes neutrahzed. The technology has been used commercially for several years. 

Thermoplastic stabilization/solidification (S/S) is a technology for the ex situ treatment of radioactive, mixed, and hazardous wastes. It is a process that uses thermoplastic polymers to physically immobilize the hazardous constituents of contaminated soils, sludges, sediments, or even liquid wastes. The idea is to prevent the migration of contaminants into the environment by forming a low-permeability solid mass. The goal of this technology is to immobilize contaminants within the existing medium, rather than to try and remove them via chemical and/or physical treatments. 

Trussed, S. Batchelor, B. 1996. Chemical characterization of pore water of a solidified hazardous waste. In Gilliam, T. M. Wiles, C, C. (eds) Stabilization/Solidification of Hazardous, Radioactive and Mixed Wastes. ASTM,... 

This Section summarizes the separate classification systems that have been developed for radioactive and hazardous chemical wastes. Impacts of the two classification systems on management and disposal of mixed wastes are also described. 

The term mixed waste refers mainly to waste that contains radionuclides regulated under AEA and hazardous chemical waste regulated under RCRA. Dual regulation of mixed waste has no effect on classification, management, and disposal of the hazardous chemical component or on classification of the radioactive component. The effects of dual regulation of mixed waste on management and disposal of the radioactive component are summarized as follows ... 

The requirements for managing hazardous chemical waste are sufficiently different from those for radioactive waste that treatment and disposal of waste that contains both types of substances is greatly impeded. Large volumes of waste that contains hazardous chemicals and radionuclides (referred to as mixed waste ) are presently being stored because the inconsistency in regulations has resulted in inadequate treatment and disposal capacity. 

Wastes have been classified for decades for a variety of purposes. This Section discusses the historical development of classification systems for radioactive and hazardous chemical wastes and the resulting classification systems in use at the present time. The relationship between waste classification and requirements for disposal of different classes of hazardous waste is emphasized. The framework for this discussion is the top-level system for waste classification in the United States shown in Figure 4.1. Within this framework, it is first determined whether a waste is nonhazardous (e.g., municipal waste) these wastes are not addressed in this Report. If a waste is deemed hazardous, it is so classified due to the presence of radionuclides or hazardous chemicals. Mixed radioactive and hazardous chemical waste is not a separate class of waste. However, mixed waste has been an important concern as a result of differences in requirements for management and disposal of radioactive and hazardous chemical wastes. Section 4.1 addresses classification and disposal of radioactive waste, and is followed by discussions of classification and disposal of hazardous chemical waste in Section 4.2 and approaches to management of mixed radioactive and hazardous chemical waste in Section 4.3. Finally, Section 4.4 summarizes previous NCRP recommendations relevant to waste classification. 

The discussions of classification of radioactive and hazardous chemical wastes and management of mixed waste in Sections 4.1 to 4.3 are presented in considerable detail to facilitate understanding of these issues by readers who may not be knowledgeable in these areas. The existing hazardous waste classification systems and the historical developments underlying them are complex. NCRP believes that an appreciation of these complexities is important in gaining an understanding of the need for a new hazardous waste classification system and the benefits it would provide. 

Transuranic Waste. Much of DOE s transuranic radioactive waste is classified as hazardous waste under RCRA and is managed as mixed waste (DOE, 1999b). Many transuranic wastes are hazardous due to the presence of toxic heavy metals or organic chemicals introduced into the waste during processing of plutonium. 

Another desirable attribute of a waste classification system that is a corollary of the system being risk-based is that it treat wastes that pose similar health risks consistently. A chemically hazardous waste estimated to pose a certain risk should be in the same waste class as a radioactive waste that poses an equivalent risk, and similarly for mixed waste. Consistency also implies that wastes posing similar risks could be disposed of using essentially the same technology (municipal/industrial landfill, licensed near-surface facility for hazardous waste, or geologic repository). 

A striving to embody all the desired attributes of the new system, while recognizing that this may take many years and that a number of important benefits can be obtained by interim implementation of parts of the system. The most important areas in which interim implementations are likely to be beneficial include the establishment of exemption levels for radionuclides and hazardous chemicals in waste, to allow hazardous wastes to be managed as nonhazardous material or to allow mixed waste to be managed as radioactive or hazardous chemical waste only, and the elimination of source-based definitions of hazardous wastes, especially radioactive wastes. 

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