Today, the bulk of household and business waste is sent to the landfills, which are huge sites designed to bury garbage and isolate it from populated areas.
These landfills are covered with soil and compacted in order to contain the waste and keep it from being blown around by the wind. Although this seems like a necessary measure, it is even more important to expose landfill garbage to the elements — sunlight, temperature, water, and air — for it to disintegrate.
Landfills, however, apply soil almost every day, which causes the waste to decompose at a very slow rate. Additionally, organic waste that requires an anaerobic — airless — environment to decompose, like a landfill, releases a gas that is made up of mostly methane, which is a greenhouse gas that contributes to climate change; methane is 30 times worse than carbon dioxide. Although landfill operators are required to combust landfill gas, the system cannot be 100% efficient, and some methane still escapes into the atmosphere.
Garbage Management: Creating Treasure from Trash
In Canada, 70 percent of the 30+ million tonnes of garbage we create a year is distributed across the more than 10,000 landfills spread across the country. Only 30% of the waste is composed, reused, or recycled, yet an estimated 50-60% of the waste sent to landfills can be composted, recycled, or reused. With many existing landfills almost full, and little interest in creating new sites near communities, there is a need for more creative waste management approaches.
When it comes to waste management, there are several strategies for reducing waste, including reusing, repurposing, and recycling. These options require creativity, innovation, and resourcefulness.
Recently, a study published in the Journal of Cleaner Production, by Uisung Lee of the Department of Energy at Argonne National Laboratory, revealed that it is possible to produce renewable natural gas and liquid fuels, such as diesel and gasoline from waste that would otherwise have gone to a landfill, and avoid the emissions of methane and other toxic gases.
Methods of Producing Energy From Waste
Waste-to-Energy (WtE) or Energy from Waste (EfW) uses various technologies to compress non-recyclable garbage in a process that both generates energy and reduces waste, in terms of lower carbon emissions and reduced impact on the environment.
The garbage used to generate energy is known as ‘biomass’. Some of the common and popular ways of transforming biomass to energy include:
This waste treatment process involves burning organic waste at high temperatures, through a process known as ‘thermal treatment’. The heat generated is then used to create energy by producing steam, which turns turbines connected to a generator. Some countries experimenting with incineration include Germany, Sweden, and Luxembourg.
This is a thermal decomposition process, known as Hydrous Pyrolysis, whereby organic waste is heated at high temperatures in the presence of water. When oxygen is eliminated from the process, it is known as Pyrolysis. The resulting thermal chemical decomposition process uses biomass and plastic as the key ingredients. They are exposed to high temperatures, resulting in a parallel change in their chemical composition, producing a gas which can be burnt.
This thermal treatment process converts carbonaceous waste into hydrogen, carbon dioxide, and carbon monoxide. Like incineration, this process applies high temperatures to the waste. However, the materials combusted also include steam and/or oxygen instead of the organic substances used in incineration. The gas produced from this process is known as Synthesis gas, which can be used as an alternate source of energy to produce heat and electricity.
Synthesis gas — syngas — can also be produced through a process known as ‘plasma arc gasification’, which uses plasma technology. A plasma torch ionizes gas to produce syngas, which is used to generate electricity while compressing the waste.
This is a non-thermal WtE garbage management process that uses microorganisms in a slow anaerobic digestion process to destroy biodegradable waste. Anaerobic means that the process takes place in the absence of oxygen. Anaerobic fermentation can be used at both the residential and commercial level to generate energy and use it.
Anaerobic processes have a good reputation because they not only help to reduce greenhouse gases in the atmosphere, but also reduce dependence on fossil fuels for energy. The technology has been particularly useful in developing countries where it is used to generate low energies for lighting and cooking in homes. China and India are renowned for their biogas systems that are used to run gas engines for small-scale applications.
Benefits of Waste-to-Energy
Energy from waste programs employ innovative technologies to improve garbage management reduce damage to our ecosystem by making the best use of waste that would otherwise have gone to the landfills. This offers numerous benefits.
The various thermal and non-thermal WtE technologies collectively save millions of barrels of oil — a non-renewable resource — being used each year. The Huntsville WtE facility alone, for instance, generates energy the equivalent to 200,000 barrels of oil per year. Any metals extracted from the ash after incineration are recycled.
Tremendous power from waste is generated in countries that encourage waste-to-energy facilities. There are about 87 EfW facilities in the US, over 500 in Europe, and over 1,600 plants in Asia that are either operating or under construction. These facilities have the ability to generate 20% or more renewable electrical power, and unlike wind or solar, available 24/7.
Methane is the most abundant gas emitted by decomposing waste in landfills. It is said to be nearly 30 times more potent than carbon dioxide as a greenhouse gas. WtE facilities reduce the production of methane.
The Renewable Energy Facility No. 2 in West Palm Beach, Florida, the most advanced waste-burning plant in North America, processes about 1 million tonnes of post-recycled municipal solid waste annually while providing 44,000 homes with enough power. Moreover, it reduces the volume of waste that would have gone to landfills by over 90%, extending the usage of existing landfills by several decades.
Waste to energy programs are a conscious effort to conserve our environment. The energy generated by these technologies is growing rapidly, compared to solar or wind power, and will continue to make a difference in domestic and commercial energy use, while saving on landfill space.
For more information on turning trash into treasure, call Red Bins on 416-733-2467 or contact us here.