The Environmental Protection Agency mentions that hazardous wastes are materials and substances that have qualities that make it dangerous or potentially harmful to human health or the environment. According to the Resource Conservation and Recovery Act, hazardous waste can have a solid, semi-solid, liquid or gaseous form and it has two categories that include listed and characteristic waste. Legal methods for disposing of hazardous waste consist of combustion and incineration, land disposal and injection wells.
List and Characteristics
There are four lists for hazardous waste as defined by the EPA and they include the F-list is for general industrial and manufacturing operations, K-list for industry-specific operations (such as petroleum and food processing), and the P and U lists for discarded commercial chemical products. EPA uses 40 CFR Part 261 Subpart C for the purpose of defining the characteristics of hazardous waste and they include ignitability, corrosivity, reactivity and toxicity.
Combustion and Incineration
Hazardous waste combustion uses two methods which include incinerators, boilers and industrial furnaces. Incinerators are primarily used to destroy or treat waste and to reduce the amount of waste. Boilers and furnaces are primarily used for energy and material recovery. Regulations governing combustion and incineration methods and practices are found in 40 CFR Part 264/265, Subpart O-Incinerators and 40 CFR Part 266, Subpart H-Hazardous Waste Burned in Boilers and Industrial Furnaces.
Land Disposal Unit
The EPA states that the most common hazardous waste disposal practices are disposal units such as landfills, surface impoundments, waste piles, land treatment units or injection wells. Subtitle C of RCRA (40 CFR Parts 264/265) gives specific information about the use of landfill options for the purpose of disposing of hazardous waste. Standards for designing landfills, surface impoundments, waste piles and land treatment units are some of the key features described in the regulations.
Injection wells are devices that place fluids such as water, wastewater, brine or water mixed with chemicals into deep underground porous rock formations or just below the surface. RCRA regulations that govern injection wells are found in 40 CFR Part 265 Subpart R, 40 CFR Part 264 Subpart X and 40 CFR Part 144 through Part 148. There are injection well classes that categorize how wells are to be constructed, their operations, their design, the depth of the well and the types of liquid substances the wells can contain. RCRA standards outline information for six injection well classes and they also provide data on various hazardous (and some nonhazardous) substances such as wastewater, fluids associated with mineral mining and radioactive waste.