Landfills, waste and sewage will be important sources of energy in the future, although it may sound strange. That future has already arrived in the developed countries that use large quantities of waste as a fuel for heating or electricity generation. In addition to trash allows production of waste energy, waste processing is primarily necessary for the protection of the environment and human health. Energy from waste is a renewable form (source) of energy. Recommended reading: Learn About Waste-To-Energy.
Solid waste can generally be divided into three basic categories:
- Municipal waste – It can be divided into: residential (housing), commercial, institutional, construction, waste from public areas and waste from water treatment plants
- Industrial waste – This waste is generated in industrial production processes, and it is significantly different in its properties from municipal waste.
- Agricultural waste – Occurs in the fields, in the vegetable gardens, orchards, vineyards, dairies and the like.
Wastes from each of these three categories can be: inert, non-hazardous or dangerous. Municipal solid waste contains organic and inorganic components. The energy potential of these two substances can be used in different ways. Production of waste energy represents an additional benefit for each community and country. The main benefits are:
- The total amount of waste is reduced 60- 90%, depending on the composition of the waste and applied technologies for energy production.
- Reducing the areas of the landfills (there are fewer areas for landfills in the world).
- By using modern technologies for this purpose, environmental pollution is reduced.
Waste incineration is the most widespread form of waste energy production. The most common forms of energy that is obtained by waste burning are thermal and electrical energy. Incinerators are similar to thermal power plants and heating plants.
Waste burning is applied to reduce the amount of waste and for the energy production. The first waste incineration furnace emerged in the second half of the 19th century. All new waste energy plants must meet certain emission standards, including those for nitrogen oxides (NO, NO2, etc.), sulfur dioxide (SO2), heavy metals and dioxins. Therefore, the modern types of incineration plants are significantly different than the old types of incinerators. Today, Japan burned nearly 2/3 of waste, and in France there are more than 300 incineration plants with a total capacity of 1.4 million tons/year.
In addition to waste incineration, there are other technologies that enable the production of energy from waste. Some of these technologies are able to convert the energy into gaseous fuels or liquid:
- Gasification – produces hydrogen, combustible gas and synthetic fuels
- Thermal depolymerization (TDP) – enables the production of synthetic crude oil
- Pyrolysis – produces combustible bio oil / tar and char
- Plasma gasification process – produces syngas including carbon monoxide and hydrogen
Apart from these thermal technologies, there are so-called non-thermal technologies for waste energy production:
- Fermentation production
- Anaerobic digestion
- Mechanical biological treatment (MBT)
Today, all EU countries and other developed countries around the world use waste energy plants, and they are willing to make large investments in this technology in the future. This will significantly help to protect the environment and save energy.