Hazardous waste. Doesn't sound very friendly, does it!? But did you know that we are surrounded by hazardous materials?!? After watching this module, you will know the characteristics that make a material hazardous, You will be able to list some of the most common household hazardous wastes as well as the basics of their management. Most of the insights for this module were taken from the website of the Basel Convention on the control of transboundary movements of hazardous wastes and their disposal. So let's get started! When is a waste material hazardous? According to the Basel Convention, hazardous wastes are any wastes that possess any of the following characteristics: explosive, flammable, combustible, oxidizing wastes or wastes containing organic peroxides, poisonous, infectious substances, toxic or ecotoxic and corrosive. All these characteristics are explained in annex 3 of the Convention. Besides, there are 18 waste streams and 27 constituents, such as zinc, arsenic and asbestos, which should be always treated as hazardous waste - unless they do not possess any of the previous hazardous characteristics. Finally, the Convention also states that wastes that are defined as hazardous in the domestic legislation of a country should also be considered as hazardous. So who generates and where is hazardous waste generated? Well obviously, hazardous waste arises from multiple sources. Industries are the biggest hazardous waste generators. In most countries however, they are responsible for managing their own waste, and therefore, their waste does not enter the municipal solid waste stream. Important generating sectors are: the chemical manufacturing, the petroleum and coal product manufacturing, mining, quarrying and dredging activities, the pulp and paper industries, wood remanufacturing facilities and the pharmaceutical industry. Small-scale businesses can also generate hazardous waste, which might be part of the municipal solid waste stream. Examples of such businesses are: car workshops, leather tanning enterprises, electroplating shops, photofinishing shops, construction and demolition companies that produce waste containing asbestos etc. Household hazardous waste. I bet that many of you are not aware of how many everyday items are hazardous or contain hazardous materials. Let's explore some common examples and the possible hazards they can pose: cleaning agents and disinfectants, aerosols, propane cylinders, batteries, cosmetics, such as hair dyes, waste products containing mercury, such as thermometers or fluorescent lightning, waste oils, paints and solvents, pesticides, pharmaceuticals, refrigerant-containing appliances, varnishes, such as a nail varnish, and e-waste. The share of household hazardous waste over the total municipal solid waste on a global basis is unavailable. However, estimates suggest less than 1 percent, but up to 5 percent if e-waste is included. Inspite of this relatively low share, its impact should not be neglected. As a side note, the parties of the Basel Convention, together with governments, municipalities and industry, have set the so-called "household waste partnership", with the objective of providing guidance on the environmentally sound management of household waste. Now that we know what hazardous waste is, let's have a look at how much we generate worldwide. This map shows the amounts of hazardous waste generated per year and reported to the United Nations Statistical Division in 2009. Notice that there is no data for many countries and be aware that the amounts reported are most likely underestimates. Unfortunately, fewer than 50 percent of the countries taking part in the Basel Convention report hazardous waste generation, import and export data. However, from those who do report, it can be estimated that at least 10 million metric tons of hazardous waste have been crossing international borders every year. Toxic waste routes is an interesting project which tries to visualize these imports and exports in an interactive tool. By clicking on the top of a country, Germany for instance, we see the amounts of hazardous waste exported in red and imported in clear orange. Each box represents an importing or exporting partner country, and by putting your cursor on top, you get more detailed information about the nature of waste and the specific amount. The management of hazardous waste has become a specialized discipline. We will use this simplified diagram to explain the main concepts. We will refer to the waste hierarchy correspondingly. Let's start with prevention. This can be done by the product manufacturers by reducing hazardousness, for example substituting toxic materials with less toxic materials, and reducing amounts by modifying manufacturing processes to follow green chemistry, increasing efficiencies and establishing new business models such as chemical leasing, which implies renting out instead of selling chemicals. Prevention can also be implemented by influencing consumers' behavior to choose products which do not contain hazardous materials. After initial consumption and before the product turns into waste, materials can be reused. This represents minimization of waste, the second layer of the hierarchy. Check for the terms "guidance on waste prevention and minimization" on the Internet to get some more insights on this issue. Then, the materials we refer to as "waste" are generated. It is imperative to source-segregate all this waste, especially the hazardous waste. Then, the waste needs to be stored. This can be done by using small containers. These containers should be labeled, indicating your name, the content, physical state, date of first and last deposition, amounts, and codes of hazard category. These containers must be kept in good condition and closed or covered in order to avoid leaks or damage and to protect them from weather. If hazardous waste is transported, generators should partner with authorized collectors to collect their waste. If such waste will cross borders from one country to another, it should be reported to the Basel Convention Secretariat, as explained in the Convention. The environmentally sound management of hazardous waste consists of several steps. First, the materials go through a pre-processing stage, where the hazardous elements are either separated, immobilized or degraded. These methods can be classified into physical, chemical, thermochemical, and bioremediation methods. Then, these materials can be stored again until they are either recycled, processed through other recovery options such as energy recovery, or finally disposed of, following the waste hierarchy. The Basel Convention includes guidelines for an environmentally sound management of numerous waste streams. For more technical guidance on specific hazardous compounds, we recommend you to search for the term "technical guidelines Basel Convention". Unfortunately, most developing countries still lack proper treatment and disposal facilities, while at the same time, they face the challenge of increasing amounts of hazardous waste - either due to increased imports or through industrialization. Most of the time, hazardous waste is mixed with non-hazardous wastes, and therefore ends up in standard landfills or dump sites or is burnt, with serious consequences for the environment. Legislation on hazardous waste can be applied on municipal, national or international levels. On municipal and national level in low- and middle-income countries, the legislative framework is either weak or absent, with poor enforcement mechanisms and low institutional capacity. On an international level, the Basel Convention is the most important regulatory framework. Several other similar Conventions that intend to regulate and control the flows of hazardous materials and wastes are shown here. For further information, you can also have a look at these sources. Let's summarize what we covered in this module. We learnt the different characteristics that make a material hazardous. We also mentioned some of the most common hazardous waste sources as well as the basics of their management. And finally, we learnt about some valuable online resources to deepen this topic.