We have long had a problem with the amount of waste we produce and what to do with it. Fossil fuels are running out and using them to create energy is having a serious impact on our environment. There are many technologies now being refined which address both these issues. These methods are collectively known as WTE or waste to energy. The simplest method is to burn waste, heating water to run a steam generator thus producing electricity. This method however does not harness all the available energy and has potential to cause pollution. Modern incinerators in developed countries are very clean however. This method of waste management just burns everything to reduce landfill so is not really a ‘green’ solution.
How to Turn Waste into Electricity
Efficient WTE starts with the collection of waste. It is much better to separate materials at the source, than to have expensive sorting facilities. When proper sorting is carried out and recyclables are removed the resulting organic materials can be treated in several ways. High energy biofuels are the result which can then be combusted to produce electricity.
- Gasification is a process that converts organic materials into a rich gas known as syngas. The material is heated to over 700 degrees celsius in a controlled amount of oxygen or steam without combustion occurring. The gases given off can be burnt at a higher temperature than the original material. This makes them far more energy efficient.
- Anaerobic digestion is a series of processes by microorganisms which break down organic material without oxygen present, resulting in methane gas. This method can also be used in the treatment of waste water.
- Fermentation processes can be be used to obtain methane and hydrogen. The advantage of hydrogen is that the byproduct of burning it is water. Making it one of the cleanest fuels know to man.
If the waste cannot be sorted before reaching the waste management plant there are techniques that can deal with it.
- Plasma gasification plants use plasma arc torches to superheat the waste. First melting then turning it to gas. Non organic material such as metals result in slag which can then be recovered. The gas produced is a high calorific fuel that is very ecologically produced. The absence of oxygen in the procedure ensures that pollutants are not formed.
- Thermal depolymerisation is a complex process that converts long chain polymers found in plastics and organics, to short chain hydrocarbons. The method mimics the geological processes thought to be behind crude oil and natural gas formation. The resulting fuels are a synthetic form of light crude and petroleum.
Make Electricity in Your Own Home
There is a relatively simple method to use called the anaerobic process, to make electricity in your own home.
- Place organic material in a container with a sealed lid.
- Run a hose from the top of the container into a second container that is submerged in water.
- Run a hose with a tap in it from the second container to a gas cooker.
The biogas is produced in the first container and travels into the second container where it is stored. When you have produced enough gas use the cooker to boil water. Transfer the steam to a turbine generator or steam engine to create electricity. A simple dynamo from a bicycle can be modified. Or a portable wind generator can be used as the turbine.
You can find more about this WTE project here.