Metals or metallic compounds are used during the manufacture of a variety of products. As a result, during processing or production operations, Industries generate wastes cantaining metals. In 1984, industry generated an estimated 5.8 billion gallons of metal-bearing wastes, including sludges, wastewaters, and treatment residues.
This section characterizes the wastes generated by major metal-waste-producing industries and addresses current waste management practices. The nine industries discussed are metal coatings; smelting and refining of non-ferrous metals; paint, ink. and associated products; petroleum refining; iron and steel manufacturing; photographic industry; leather tanning; wood preserving; and battery manufacturing. Waste streams from each of these industries have unique characteristics; however, the wastes also contain cotnnon metals, such as aluminum (AT), arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), nickel (Ni), silver (Ag), and zinc (Zn).
Table 1 presents the number of metal-waste generators (as of 1983) by Standard Industrial Classification (SIC) code for several major industry categories. Table 2 provides a breakdown of the metal-bearing wastes by 0, F, and K EPA Hazardous Haste codes. Table 3 presents estimates of the quantities of the wastes handled by landfilling, storage, or treatment. Although new technologies for metal recovery have emerged, only about half of the industries that generate metal wastes recover the metals from wastewaters and sludges. Ion exchange for recovery of electroplating baths and chemical precipitation of photographic developing baths are examples of current recovery methods being used. Table 4 presents brief descriptions of the hazardous wastes generated fro» the major industry categories included in this study. Table 5 presents average compositional data on six toxic metals for several of these waste categories; other metals such as zinc and copper may also be found in many of the wastes, e.g. F0Q6, K061. Each of the major metal-waste-generating industries are discussed in more detail in the subsections that fallow.
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