What is Hazardous Waste?
Hazardous waste is a special category of debris that requires careful handling during the disposal process. This is due to the hazardous nature of the material, the properties of which may pose a substantial threat to public health or the environment. Common properties associated with hazardous waste include toxicity, flammability, radioactivity and corrosiveness. Due to the danger posed by these materials, hazardous waste disposal is heavily regulated on the local, state, and federal level in order to keep it separate from the municipal solid waste stream.
Types of Hazardous Waste
There are four categories of hazardous waste:
Listed wastes are those specific wastes that have been identified by the EPA as being hazardous. These wastes include the byproducts of common manufacturing and industrial process, as well as substances used to clean machinery. Wastes produced by specific industries are also included under this category, such as petroleum refining or chemical manufacturing.
Characteristic wastes are those not explicitly listed by the EPA as hazardous, but are still considered hazardous because they exhibit characteristics of ignitability, corrosivity, reactivity, or toxicity. Some common examples of ignitable wastes are used oils or solvents, while corrosive waste consists of acids or bases that can corrode their storage containers (barrels or drums). Reactive wastes are materials or substances that are unstable under normal conditions and can create deadly vapors, explosions, or fumes. Toxic waste is generally fatal if ingested or absorbed by the body and is tightly regulated to ensure that they do not leach into groundwater supplies.
Universal wastes are a common type of hazardous waste that the EPA has streamlined collection and disposal regulations for in order to encourage retailers and municipalities to start their own collection programs. Common examples include: fluorescent tubes, mercury-containing thermometers, car batteries, and pesticides.
Mixed wastes classify those materials that contain both hazardous waste and radioactive waste. This category of waste is generated by nuclear power plants, nuclear weapon production, and medical diagnostic services and research. Radioactive waste is regulated by the Department of Energy and the U.S. Nuclear Regulatory Commission, while the EPA regulates the hazardous portion.
Some Fast Hazardous Waste Facts
- Radioactive materials are notoriously difficult to store safely, especially the millions of tons of nuclear waste that originates from power plants. The United States has invested some $9 billion on a facility called the Yucca Mountain nuclear waste repository that is specifically designed to store the nation's nuclear waste for thousands of years. The EPA's own compliance standards for the site have been enacted for a time period of 10,000 years. Beyond that, the EPA has required the Department of Energy to demonstrate that the site will be able to safely contain its nuclear cargo for a staggering 1,000,000 years, taking into account earthquakes, volcanoes, and climate change.
- Think all hazardous waste comes in glowing green barrels? A lot of common household goods contain hazardous chemicals, requiring them to be disposed of separately from regular trash. This includes TV's, batteries, cell phones, refrigerators, paints, and more. This type of hazardous waste is so common that the EPA streamlines its regulation so that more commercial and municipal programs can be created to divert these items from landfills.
- Roughly 34 million tons of hazardous waste is produced in the US every year. And almost half of that waste is produced in Texas, which generates 15.6 million tons per annum. Why is that? Texas is home to some 29 oil & gas refineries (more than the average nation has!) which generate a variety of hazardous byproducts. Texas is also a large industrial state, further contributing to its large share of hazardous waste production.
- Discarded tires are not generally classified as hazardous waste, but you still won't find them inside landfills. That is because tires capture methane inside their inner wall, causing them to bubble to the surface of the landfill, destroying liners and pipes in the process.
Where does hazardous waste go?
Since you can't put hazardous materials in a trash can, or a dumpster for that matter, where does all the waste go? There are many different ways that hazardous materials are treated, ranging from incineration to recycling.
There are a whole lot of materials that can be recycled, such as electronic circuit boards and televisions. One of the most recycled forms of hazardous waste is batteries. The process for recycling batteries is relatively simple, assuming you have the right equipment. With just a little heat and technical know-how, battery recyclers can melt down the metal contained within the battery and recast it into new batteries. This process is particularly efficient for lithium-ion batteries which are used in virtually all consumer electronics.
Other types of hazardous waste are completely destroyed through the use of incinerators and waste-to-energy plants. Incineration is particularly popular for disposing of medical waste because it destroys non-recyclable infectious waste, while also allowing used medical instruments to be recycled. These incinerators operate at high-temperatures, ranging from 4,000 to 7,000 degrees Fahrenheit, in order to burn up the debris and transmute toxic emissions into less harmful gases. Modern incinerators include sophisticated ventilation systems that drastically reduce the level of emissions from these plants.
But not all forms of hazardous waste can be recycled or incinerated, requiring them to be stored. One method of containing toxic sludge is to mix it with cement, hardening the waste inside so that it becomes a stable solid form. The resulting cement blocks are less toxic and can be stored easily inside appropriate storage facilities. Concrete is also used extensively in the construction of casks used for transporting and storing radioactive waste. Not only is concrete hard to break, but it also absorbs radiation very well.
There are also such things as hazardous waste landfills that are built specifically to contain hazardous waste. Unlike municipal landfills, these disposal sites are built with additional containment safeguards such as concrete foundations, as well as being cited in underground mines or caves.