Waste incineration definition
Incineration is one of the waste treatment methods used currently to deal with tremendous amounts of human-made garbage created every single day. It is part of the thermal waste treatments, as it uses high temperatures. This process involves the combustion of organic substances contained in waste materials.
Incineration converts waste into ash, flue gas and heat. Ashes are mostly formed by the inorganic constituents of the waste and may take the form of solid lumps or particulates carried by the flue gas. The flue gases must be cleaned of gaseous and particulate pollutants before these are released into the atmosphere.
In the past, incineration was only conducted without separating materials thus causing harm to people nearby. This resulted in risk for plant workers and the environment. Most of such plants and incinerators never separated the most harmful pollutants nor generated electricity, and nowadays there are still many that don’t do it.
As mentioned, in some incineration plants, the technique is used for generation of electric power, which is a good way to benefit from this process. However, there is still a lot of improvement to be made in the origin of the problem: generate less garbage or recycle correctly the humans’ waste, especially transforming organic waste into composting.
The problem with waste is that, even planet earth is huge, we don’t have enough land to fulfill with garbage. Even though incineration generates waste, the mass is reduced by approximately 95%, which makes the landfill problem way more easy.
Other waste-to-energy techniques
Waste incineration is by far the most used process on the garbage treatment, but currently there are other techniques used to convert this trash into power energy:
- Anaerobic digestion
Types of waste to incinerate
Municipal solid waste
It is the solid portion of the waste (not classified as hazardous or toxic) generated by households, commercial establishments, public and private institutions, government agencies, and other sources. This waste stream includes food and yard wastes, and a multitude of durable and non-durable products and packagings.
Hazardous waste is defined by EPA under the Resource Conservation and Recovery Act (RCRA) as a waste material that can be classified as potentially dangerous to human health or the environment on the basis of different criteria. This type of waste is found usually on manufacturers, service and wholesale-trade companies, universities, hospitals, government facilities, and households.
The hazardous waste can be classified as a threat for the following reasons:
- Waste of easy ignition
- Corrosive waste for materials and/or people
- Reactive waste: meaning it can explode, catch fire or give up harmful gases.
- Toxic waste
Medical waste management
Usually biomedical, this type of waste can have infectious or toxic characteristics, so they need to be treated correctly to avoid creating a public health issue. The whole medical industry generates medical waste, but hospitals are the main medical waste generators, with almost 30 pounds per day per hospital on average.
Waste incineration causes air pollution
Mass cannot be created nor destroyed, so the reduction of volume during the waste incineration process has its effects, and that is the emission of flue gas to the atmosphere. In other words, air pollution. These different types of emissions depend on the waste incinerated:
Furans and dioxins
The emission of furans and dioxins is the biggest issue in the waste incineration process, giving that these are staidly injurious to health. Some governments have regulated these types of activities and obliged incineration plants to buy new machinery equipped with special equipment to clean emission of gases from these injurious components.
Carbon dioxide (CO2), a major player in the global warming issue, is also produced in vast amounts during garbage incineration. These emissions are due to materials that include carbon in its composition, when incinerated, produce carbon dioxide.
A part from the major gases mentioned, a huge variety of other gases are emitted during the incineration of trash. On this large list, the most present volatiles are: sulfur dioxide, hydrochloric acid, fine particles and heavy metals.