Characterization
The goal of characterization is to obtain data necessary to determine how to safely and efficiently package and transport the wastes for treatment and/or disposal.
If wastes are bulked, they must be sufficiently characterized to determine which of them can be safely combined.
Standard compatibility tests are simple, rapid, and cost-effective procedures used to segregate wastes into broad categories, including water reactive, oxidative, and radioactive.
By identifying broad waste categories, compatible waste types can be safely bulked on-site without the risk of fire or explosion, and disposal options can be determined without exhaustive and costly analysis of each drum. In some cases, however, further analysis may be necessary to identify the waste materials more precisely.
During the compatibility testing process, each drum is scanned for radioactivity as it is opened.
- If the scan is negative, a sample is taken to perform the compatibility test. (Solid samples should be taken from several different areas within the drum.)
- The contents of all drums should be described on the drum data sheet in terms of physical state, viscosity, and number of phases.
- A sample should be taken for each phase.
There are a number of published compatibility testing protocols developed by the Chemical Manufacturers' Association (CMA). However, procedures must be tailored for site-specific conditions. Based on the CMA protocol, wastes are segregated into broad waste categories, including:
- Liquids: radioactives, peroxides and oxidizing agents, reducing agents, and water-reactive compounds
- Water insolubles: low halogen/low PCB, mixed halogen/high PCB, and high halogen/low PCB
- Acids: strong (pH less than 2), Weak (pH 2-7)
- Bases: strong (pH more than 12) with or without cyanides or sulfides, and weak (pH 7-12) with or without cyanides or sulfides
- Solids: radioactive and non-radioactive
This protocol also requires that a compatibility test be performed by mixing small samples of wastes that are intended to be bulked, making visual observations for precipitation, temperature changes, or phase separation.
When possible, materials should be characterized using an on-site laboratory to minimize the time before appropriate action can be taken to handle any hazardous materials. If samples must be analyzed off-site, samples should be packaged on-site in accordance with DOT regulations ( 49 CFR Parts 171-178) and shipped to the laboratory for analysis.
Knowledge Check Choose the best answer for the question.
3-10. Based on the Chemical Manufacturers' Association (CMA) protocol, _____ must be performed by mixing small samples of wastes.
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