Waste To Energy
Waste, is what people throw away when they feel they no longer have a need for it. Almost everything we do creates waste at home, in the community, socially and at our work places.
This process is of using up the earth’s natural resources to make products and throwing them away shortly afterwards is not sustainable and it is causing havoc worldwide. Our consumption levels directly impact the kind of world we’ll leave for future generations.
Did you know?
Almost 90% of everything we buy becomes waste within six weeks of purchase! However, some innovative energy companies in Japan and Europe have found a solution to this, by taking this waste and using it to generate power! A 1,000 ton per day waste-to-energy plant can produce enough electricity for 15,000 households. This means that each ton of waste can power a household for a month!
Regular power plants use coal, oil and natural gases. Burning fuel is used to heat steam that drives a turbine to generate electricity. Waste-to-energy plants use waste that is collected from dumpsites, as fuel to generate power. This process has been proven to reduce a community’s landfill volume by up to 90%. Materials like kitchen waste, bio waste and commercial waste are ideal for combustion. Examples of these are paper, cardboard, food waste, grass clippings, leaves, wood, leather products and plastics.
The process of converting waste-to-energy in simple terms can be explained like this.
- The waste material is received in an enclosed receiving area, where it is mixed and blended in preparation for combustion.
- A giant claw on a crane grabs the waste and puts it in a combustion chamber. The mixed waste is then funneled into the combustion chamber on a timed moving grate.
- The waste is burned, it is continuously turned to keep it exposed and burning. The fire releases heat. It is poked like a log in a fireplace, which injects oxygen and fumes to ensure a complete burn of the waste.
- The heat is then used to turn water into steam. The high-pressure steam turns the blades of a turbine generator to produce electricity.
- Environmental Controls – An air pollution control system removes pollutants from the combustion gas then it is released through a smoke stack.
- The unburned remains of combustion "bottom ash" are collected by magnets and eddy current separators to remove both steel and iron. Other metals such as copper, brass, nickel, and aluminum are also collected for recycling. The remaining ash can be used for roadbeds and rail embankments. Ash is generated at a ratio of about 10% of the waste’s original volume and 30% of the waste’s original weight.
- The “fly ash” is captured in a filter bag, where an induction fan draws air through fabric bags. The bags are vibrated at intervals to shake loose particulates on their inner and outer surfaces. The carbon or charcoal is treated with oxygen to increase its porosity and then injected into the hot gases to absorb and remove heavy metals e.g. mercury and cadmium. The remaining 6% captured fly ash is treated and often returned to landfills.
Think of municipal solid waste as a mixture of energy rich fuels. Out of a ton of waste, more than 900 kilograms can be burned into energy. Every person is entitled to a clean environment and that is why governments need to establish these WtE plants to create an efficient and sustainable waste management system to ensure we achieve the dream and vision of living in a clean healthy environment. Japan and some European countries are well on their way to achieving this by the means of these plants. I am pretty sure that Africa can also implement the same strategy, to eradicate the over flowing landfill dumpsite whilst delivering much needed electrical power and employment in their communities.