Hazardous waste
Hazardous waste is waste that must be handled properly to avoid damaging human health or the environment. Waste can be hazardous because it is toxic, reacts violently with other chemicals, or is corrosive, among other traits. As of 2022, humanity produces 300–500 million metric tons of hazardous waste annually. Some common examples are electronics, batteries, and paints. An important aspect of managing hazardous waste is safe disposal. Hazardous waste can be stored in hazardous waste landfills, burned, or recycled into something new. Managing hazardous waste is important to achieve worldwide sustainability. Hazardous waste is regulated on national scale by national governments as well as on an international scale by the United Nations and international treaties. A controlled waste is subject to legislative control in its handling or its disposal.
Types
Universal wastes
s are a special category of hazardous wastes that generally pose a lower threat relative to other hazardous wastes, are ubiquitous and produced in very large quantities by a large number of generators. Some of the most common "universal wastes" are: fluorescent light bulbs, some specialty batteries, cathode-ray tubes, and mercury-containing devices.Universal wastes are subject to somewhat less stringent regulatory requirements. Small quantity generators of universal wastes may be classified as "conditionally exempt small quantity generators" which release them from some of the regulatory requirements for the handling and storage hazardous wastes. Universal wastes must still be disposed of properly.
Household Hazardous Waste
Household Hazardous Waste, also referred to as domestic hazardous waste or home generated special materials, is a waste that is generated from residential households. HHW only applies to waste coming from the use of materials that are labeled for and sold for "home use". Waste generated by a company or at an industrial setting is not HHW.The following list includes categories often applied to HHW. It is important to note that many of these categories overlap and that many household wastes can fall into multiple categories:
- Paints and solvents
- Automotive wastes
- Pesticides
- Mercury-containing wastes
- Electronics
- Aerosols / Propane cylinders
- Caustics / Cleaning agents
- Refrigerant-containing appliances
- Some specialty batteries
- Ammunition
- Asbestos
- Car batteries
- Radioactive wastes.
Disposal
Recycling
Some hazardous wastes can be recycled into new products. Examples may include lead–acid batteries or electronic circuit boards. When heavy metals in these types of ashes go through the proper treatment, they could bind to other pollutants and convert them into easier-to-dispose solids, or they could be used as pavement filling. Such treatments reduce the level of threat of harmful chemicals, like fly and bottom ash, while also recycling the safe product.Incineration
Incinerators burn hazardous waste at high temperatures, greatly reducing its amount by decomposing it into ash and gases. Incineration works with many types of hazardous waste, including contaminated soil, sludge, liquids, and gases. An incinerator can be built directly at a hazardous waste site, or more commonly, waste can be transported from a site to a permanent incineration facility.The ash and gases leftover from incineration can also be hazardous. Metals are not destroyed, and can either remain in the furnace or convert to gas and join the gas emissions. The ash needs to be stored in a hazardous waste landfill, although it takes less space than the original waste. Incineration releases gases such as carbon dioxide, nitrogen oxides, ammonia, and volatile organic compounds. Reactions in the furnace can also form hydrochloric acid gas and sulfur dioxide. To avoid releasing hazardous gases and solid waste suspended in those gases, modern incinerators are designed with systems to capture these emissions.
Landfill
Hazardous waste may be sequestered in a hazardous waste landfill or permanent disposal facility. "In terms of hazardous waste, a landfill is defined as a disposal facility or part of a facility where hazardous waste is placed or on land and which is not a pile, a land treatment facility, a surface impoundment, an underground injection well, a salt dome formation, a salt bed formation, an underground mine, a cave, or a corrective action management unit."Pyrolysis
Some hazardous waste types may be eliminated using pyrolysis in a high temperature not necessarily through electrical arc but starved of oxygen to avoid combustion. However, when electrical arc is used to generate the required ultra heat all materials introduced into the process will melt into a molten slag and this technology is termed Plasma not pyrolysis. Plasma technology produces inert materials and when cooled solidifies into rock like material. These treatment methods are very expensive but may be preferable to high temperature incineration in some circumstances such as in the destruction of concentrated organic waste types, including PCBs, pesticides and other persistent organic pollutants.In society
Management and health effects
Hazardous waste management and disposal comes with consequences if not done properly. If disposed of improperly, hazardous gaseous substances can be released into the air resulting in higher morbidity and mortality. These gaseous substances can include hydrogen chloride, carbon monoxide, nitrogen oxides, sulfur dioxide, and some may also include heavy metals. With the prospect of gaseous material being released into the atmosphere, several organizations developed an identification scale in which hazardous materials and wastes are categorized in order to be able to quickly identify and mitigate potential leaks. F-List materials were identified as non-specific industrial practices waste, K-List materials were wastes generated from specific industrial processes - pesticides, petroleum, explosive industries, and the P & U list were commercially used generated waste and shelf stable pesticides. Not only can mismanagement of hazardous wastes cause adverse direct health consequences through air pollution, mismanaged waste can also contaminate groundwater and soil. In an Austrian study, people who live near industrial sites are "more often unemployed, have lower education levels, and are twice as likely to be immigrants." This creates disproportionately larger issues for those who depend heavily on the land for harvests and streams for drinking water; this includes Native American populations. Though all lower-class and/or social minorities are at a higher risk for being exposed to toxic exposure, Native Americans are at a multiplied risk due to the facts stated above. Improper disposal of hazardous waste has resulted in many extreme health complications within certain tribes. Members of the Mohawk Nation at Akwesasne have suffered elevated levels of PCB in their bloodstreams leading to higher rates of cancer.Global goals
The UN has a mandate on hazardous substances and wastes with recommendations to countries for dealing with hazardous waste. 199 countries signed the 1992 Basel Convention, seeking to stop the flow of hazardous waste from developed countries to developing countries with less stringent environmental regulations.The international community has defined the responsible management of hazardous waste and chemicals as an important part of sustainable development by including it in Sustainable Development Goal 12. Target 12.4 of this goal is to "achieve the environmentally sound management of chemicals and all wastes throughout their life cycle". One of the indicators for this target is: "hazardous waste generated per capita; and proportion of hazardous waste treated, by type of treatment".
Regulatory history
In the United States
Resource Conservation and Recovery Act (RCRA)
In the US, hazardous wastes are regulated under the Resource Conservation and Recovery Act, Subtitle C. Hazardous wastes are wastes with properties that make them dangerous or potentially harmful to human health or the environment. Hazardous wastes can be liquids, solids, contained gases, or sludges. They can be by-products of manufacturing processes or simply discarded commercial products, like cleaning fluids or pesticides. In regulatory terms, RCRA hazardous wastes are wastes that appear on one of the four hazardous wastes lists, or exhibit at least one of the following four characteristics; ignitability, corrosivity, reactivity, or toxicity.By definition, EPA determined that some specific wastes are hazardous. These wastes are incorporated into lists published by the Agency. These lists are organized into three categories: F-list found in the regulations at 40 CFR 261.31, K-list found in the regulations at 40 CFR 261.32, and P-list and the U-list found in the regulations at 40 CFR 261.33.
RCRA's record keeping system helps to track the life cycle of hazardous waste and reduces the amount of hazardous waste illegally disposed.