ASTM E2060-22

SIGNIFICANCE AND USE 4.1 General—CCPs can have chemical and mineralogical compositions that are conducive to use in the chemical stabilization of trace elements in wastes and wastewater. These elements include, but are not limited to, arsenic, barium, boron, cadmium, chromium, cobalt, lead, molybdenum, nickel, selenium, vanadium, and zinc. Chemical stabilization may be accompanied by solidification of the waste treated. Solidification is not a requirement for the stabilization of many trace elements, but does offer advantages in waste handling and in reduced permeability of the stabilized waste. This guide addresses the use of CCPs as a stabilizing agent with or without addition of other materials. Note 1: In the United States, S/S is considered the BDAT for the disposal of some wastes that contain metals since they cannot be destroyed by other means (2). 4.1.1 Advantages of Using CCPs—Advantages of using CCPs for waste stabilization include their availability in high volumes, and generally good product consistency from a single source. In addition, in some instances certain CCPs can partly or entirely replace other expensive stabilization materials such as Portland cement. CCPs vary depending on the combustion or emission control process and the coal or sorbents used, or both, and CCPs contain trace elements, although usually at very low concentrations. CCPs are generally an environmentally suitable materials option for waste stabilization, but the compatibility of a specific CCP must be evaluated with individual wastes or wastewater through laboratory-scale tests followed by full-scale demonstration and verification. CCPs suitable for the chemical stabilization have the ability to incorporate large amounts of free water via hydration reactions. These same hydration reactions frequently result in the formation of mineral phases that stabilize or chemically immobilize the trace elements of concern. CCPs that exhibit high pHs (>11.5) offer advantages in stabilizing trace elements t... SCOPE 1.1 This guide covers methods for selection and application of coal combustion products (CCPs) for use in the chemical stabilization of trace elements in wastes and wastewater. These elements include, but are not limited to, arsenic, barium, boron, cadmium, chromium, cobalt, lead, molybdenum, nickel, selenium, vanadium, and zinc. Chemical stabilization may be accompanied by solidification of the waste treated. Solidification is not a requirement for the stabilization of many trace elements, but does offer advantages in waste handling and in reduced permeability of the stabilized waste. 1.1.1 Solidification is an important factor in treatment of wastes and especially wastewaters. Solidification/Stabilization (S/S) technology is often used to treat wastes containing free liquids. This guide addresses the use of CCPs as a stabilizing agent (with or without the addition of other materials. Stabilization may be achieved by using combinations of CCPs and other products such as lime, lime kiln dust, cement kiln dust, cement, and others. CCPs used alone or in combination with other reagents promote stabilization of many inorganic constituents through a variety of mechanisms. These mechanisms include precipitation as hydrates, carbonates, silicates, sulfates, and so forth; microencapsulation of the waste particles through pozzolanic reactions; formation of metal precipitates; and formation of hydrated phases (1-4).2 Long-term performance of the stabilized waste is an issue that must be addressed in considering any S/S technology. In this guide, several tests are recommended to aid in evaluating the long-term performance of the stabilized wastes. 1.2 The CCPs that are suited for this application include fly ash, dry flue gas desulfurization (FGD) material, and and fluidized-bed combustion (FBC) ash. 1.3 The wastes or wastewater, or both, containing the inorganic species may be highly variable, so the chemical characterist...