People produce a lot of trash, so Sustainable Waste Management (SWM) is essential for 21st century society.
Prof. Nickolas Themelis of Columbia University and the Waste to Energy Research and Technology Council, explains how Waste to Energy can help us in reducing landfill waste, while producing energy.
Waste Production and Waste Management
One of the problems that our society is currently facing is the generation of increasing quantities of wastes.
Moreover, often the wastes are made of materials of increasing complexity, due to the developments in technology.
Plastics or metals, for instance, often contain small amounts of other compounds (additives), to give the materials special properties.
It is expected that this problem will get even worse in the coming years, as greater quantities of more complex wastes will be generated.
For these reasons, it is important and essential to develop strategies for sustainable waste management.
Recycling Non-Toxic Waste
The technology we implement in recycling waste is different depending on the kind of wastes, and the possible dangers associated with them. Materials which contain no hazardous chemicals, for instance, should be recycled and successively reused.
Surely recycling should be encouraged, developed and performed as much as possible; there are limits to the recycling process. These limits can be due, for instance, to a “human” element – some people may not make enough effort to recycle. There can also be technical limits: some materials may lose some of their original properties during the recycling process and, consequently, they cannot be reused. Because of these issues, we must consider valid post-recycling options.
Landfilling is, at present, the most common solution for non-recycled wastes. According to a report published in 2007, 1 billion tons per year of municipal solid waste (MSW) are disposed in landfills around the world.
The consequences on the environment of this practice can vary, depending on the way the landfilling is done; in more developed countries, for instance, strict legislation is in place to control the composition of the landfilled materials and the possible leaks into the surrounding environment. This, however, is not always the case in less wealthy and developed countries.
One of the most serious problems associated with landfilling is the emission of landfill gases, principally methane (CH4). The global amount of emitted CH4 was estimated to be about 50 million tons per year; only a small portion (6 million tons) is recovered for successive use. Methane is a much more powerful greenhouse gas than CO2, so the dangers associated with such emissions are clearly understandable.