# Applications of Plasma Produced with Electrical Discharges in Gases for Agriculture and Biomedicine
## 3 Review of Plasma Applications in Agriculture and Medicine
### Plasma Applications in Agriculture  
Industrial and municipal waste, including toxic and post-hospital waste, resulting from the progressive development of civilisation throughout the world in recent centuries, is a serious problem for the natural environment and its main components: air, water, and soil. To counteract this, effective methods for their disposal and management are sought. Despite significant progress in this area, there are still technological difficulties that limit the achievement of the expected environmental and economic benefits. A review of plasma technologies in the management of solid and liquid industrial and municipal wastes was performed in [47]. Given are examples of the thermal technology of plasma generated in arc furnaces, used on an industrial scale in the metallurgical processing of materials. Arc furnaces, as sources of thermal plasma [106], are also used in the recovery of materials from the metallurgical industry and steel processing and of noble metals from the platinum group from used catalysts; waste disposal containing asbestos, radioactive, electronic, oil, petrochemical and mining pollutants. This waste contains both hazardous materials that can have a very detrimental effect on local ecosystems and also on valuable elements, usually precious metals.  
The plasma process based on thermal arc discharge was designed in such a way as to separate metals and minerals from the waste material while destroying elements hazardous to the environment. The same thermal arc technology can also neutralise gaseous pollutants generated in the combustion of liquid and solid wastes. Despite the significant advancement of the arc plasma thermal technology in environmental protection, research is still being conducted around the world on processes to convert industrial and municipal waste into energy [106]; liquid and gaseous fuels [73; 124]; the treatment of medical waste [103; 125]; sewage sludge [126]; taming sludge [127]; organochlorine waste [128]; and contaminated soil [15; 19; 80; 83].  
In Poland, research on thermal arc plasma technology is conducted on a large scale, e.g., at the Technical University of Lodz [15; 105; 123; 126], Silesian Technical University [105], and Czesetchowa Technical University [127]. This research concerns the disposal of solid waste by means of arc discharges, which leads to the thermal decomposition of the organic fraction and the melting of the inorganic fraction which, as a result of the cooling process, cause vitrification of the waste material. An example of such a process is the utilisation of ash and sedimentation wastes. At a temperature for the arc plasma at approximately 2300 K [15; 105], the ash melts, and after cooling obtains the structure of glass. Many waste materials can be plasma vitrified. These include residues of combustion processes (ash, slag, and sedimentation deposits), inorganic hazardous waste (asbestos), and industrial sewage waste (galvanic residues). The most important advantages of the vitrification process include [10; 105; 123]:  
* Release of the product from organic compounds and their destruction.
* Dissolving or freezing elements and toxic compounds (heavy metals) in the vitrified product.
* Mass and volume reduction in the process of degassing and decomposition of oxides.
* Resistance of the obtained product to the action of organic compounds, and its good physical properties (hardness, resistance to abrasion, and high temperatures).  
Thermal plasma offers some unique advantages in destroying hazardous waste compared with classical incineration. The high energy density and temperature associated with thermal plasma and the high rates of plasma-chemical reactions make it possible to treat large amounts of waste in relatively small reactors. In addition, thermal plasma reactors (arc furnaces) can be easily integrated into a production process that generates hazardous waste, allowing for its disposal at the point of origin.