Although still little known to many, plasma is the state of matter that is most present in the universe. It was first identified by Sir William Crookes in 1879, was named by Irving Langmuir in 1920 and is considered the fourth state of matter. Plasma is an ionized gas; that is, its molecules have lost one or more electrons. We can observe it in the stars and aurora borealis, in lightning and in the Earth’s magnetosphere, although it can also be created artificially.
In recent years there has been a growing interest in studying plasma behavior and finding ways to exploit it in different applications. Plasma is used in the microelectronics, automotive, aerospace and medical industries; as a resource for cleaning and surface treatment and to obtain biocompatibility in different types of materials. Its use is considered environmentally friendly due to low waste generation and low energy consumption.
The great industrial development that we have recently experienced globally has generated a need to exploit energy alternatives and take advantage of resources, focusing on technological innovation, competitiveness and productivity.
In Costa Rica there is the Plasma Laboratory for Fusion Energy and Applications at the Tecnológico de Costa Rica, directed by Dr. Iván Vargas Blanco, specialist in Plasma Physics and Nuclear Fusion. The Laboratory opened its doors in 2011 and currently has the participation of officials and students of the institution, who investigate plasma for applications in fields such as fusion, medicine, agriculture and industry.
The Laboratory focuses on research on alternative energy from nuclear fusion and industrial applications of plasmas. As part of this research, in 2012 Dr. Vargas published the report “Determination of the potential and requirements to apply plasma gasification technology in waste treatment and electric energy production in the country”. In this report, Dr. Vargas proposes the implementation of thermal plasma treatments as an alternative or complement for waste management in the country. The research was proposed taking into consideration municipal solid waste, hospital solid waste and toxic chemicals.
Gasification
Waste treatment methods using plasma have been investigated and even applied in different countries. At the Bariloche Atomic Center in Argentina, they are working on the development of a plasma gasification system to treat hospital waste more safely and efficiently. It is hoped that this system can be installed in hospitals and sites that generate hazardous waste to reduce the volume, handling and transportation of this waste.
Sierra Energy applies FastOx gasification technology to break down waste at the molecular level, using steam and oxygen. This technology converts organic materials into a synthetic gas with high energy density, and inorganic materials are melted into stone and metals that do not generate leachate. This waste is converted into a synthetic gas without particulate matter and tar, making it viable for generating high-value end products.
An additional benefit of syngas generated from plasma waste gasification is that it can produce electricity with even lower emissions than natural gas. For the application of this type of process, waste separation is not required, so it represents a practical method that can reduce the volume and weight of solid waste by up to 97%.
The implementation of this method for the treatment of municipal waste may not be feasible for the time being in the country, due to the large amount of economic and intellectual resources required. However, it may be profitable on a smaller scale, as in the case of solid hospital and chemical waste.
In the plasma vitrification process, the waste is mixed with silicate-rich additives and exposed to high temperatures. At the end of the process, crystals are obtained that are inert to most chemical and biological agents and can be used as a high-quality composite in the construction of roads, pavements and slopes.
Need
According to data from the United Nations (UN), it is estimated that human beings generate more than 2 billion tons of solid waste per year and that if there is no drastic change in our practices, the number will increase to 4 billion tons by 2050. The best way to avoid reaching this extreme is to reduce the amount of waste we generate, but what do we do with the 7 billion tons of waste that currently flood our planet?
Of the eight approved landfills operating in Costa Rica, seven are reaching or have already reached the end of their useful life and one is out of service. Recycling is also insufficient. Many households have not yet adopted the practice, some municipalities have not implemented the collection and management of waste suitable for recycling, and the places that have recyclable waste management often receive materials that cannot be treated in our country and end up in a landfill.
The waste crisis is imminent. Concrete, real and, above all, effective actions are required. Will plasma be the solution?