Waste to Energy: A Guide to Sustainable Waste Management Technology
Waste-to-Energy (WtE) is one of the most efficient waste management technologies all over the globe. It provides an alternative source of renewable energy. Australia has been slow to adopt waste-to-energy technologies compared to world-leaders like Sweden, but there are many reasons why it is slowly but surely becoming the ultimate municipal waste management course of action.
In this article, let's discuss waste to energy (WtE) as a corresponding method of waste recycling and a part of waste management.
Waste to Energy (WtE) sustainability
Waste to energy (WtE) is a crucial aspect of a sustainable waste management chain that describes a method of generating energy from all kinds of municipal solid waste (MSW). This process utilizes waste to produce fossil fuel alternative energy in the forms of heat, gas, and electricity. From local councils to municipal waste management businesses and energy sectors, the large-scale WtE projects involve a different range of stakeholders and technologies. The procedures, outputs, and residues depend on the nature of the feedstock waste materials.
Here are some of the aspects of WtE-
• Reduced net Greenhouse Gas: WtE technology has a great contribution in avoiding the mass production of methane and other contaminants while generating 20 times more renewable energy from each ton of waste. On top of that, it is notably the only economically and ecologically sound solid waste disposal option with guaranteed state-of-the-art air pollution control technology.
• Reduced Landfill usage and landfill expansions: Fully complementary to recycling, WtE technology typically reduced waste volumes by 90%. This means, fewer landfills will be needed to process waste and will protect another valuable natural resource – land.
• Facilitation of generated energy in the form of electricity or fuel: WtE technology can reduce the reliance on energy imports and the environmental cost of transporting energy-fuel sources. This form of renewable energy can be used alongside wind and solar for sustainable waste management and energy solutions.
Ways of Waste to Energy conversion
Broadly, WtE technology falls into two main categories: the thermochemical processing and biochemical processing of municipal solid waste (MSW). The renewed thermal energy is usually transformed into electrical energy, and the bio-chemical energy is converted into high-energy fuel pellets.
Processing these two categories include a range of techniques as well, including gasification, combustion, thermal depolymerization, pyrolysis, and so on. Like mentioned before, the WtE project type solely depends on the characteristics of the feedstock landfill waste material.
Gasification is a unique process that converts carbon-based waste material or biomass, into usable synthesis gas. With a specific chemical reaction process in high temperature, gasification turns municipal solid waste (MSW) into higher-value commercial products like fertilizers, transportation fuels, and even alternatives to natural gas, without actually burning at all.
Pyrolysis method is defined as the thermal decomposition and a prospective waste plastic conversion into low-emissive hydrocarbon fuel or heavy oil. It’s a technology of heating and decomposing organic waste materials in an oxygen-deficient environment at temperatures between 400-650 degrees Celsius. In general, pyrolysis is an inexpensive technology used widely in the chemical and waste conversion industry for processing a wide variety of feedstock. It generates high-energy synthetic gas for producing electricity.
Incineration process involves heating organic waste compounds at a high temperature and creating thermal energy and fossil- in the presence of water. It also deforms the molecular structure that is required for organic poisons and generates fuels that are sulfur-free and chemically harmless.
• Anaerobic digestion:
Anaerobic digestion is a widely accepted WtE technology of biological processes in which microorganisms break down biodegradable waste materials. In the absence of oxygen, the waste is converted into methane to produce methane and to use for heat and electricity generation subsequently.
• Methane fermentation:
Methane fermentation is an anaerobic process to transform agricultural and other organic waste containing lipids, proteins, carbohydrates etc. into energy. The value-added outcome of this anaerobic fermentation includes biogas, lactic acid, ethanol, biohydrogen, volatile fatty acids (VFAs) and so on.
Problems with solid waste landfills
Unfortunately, despite being one of the very few options, landfill doesn’t process solid waste very effectively. Waste landfill generates a tremendous amount of greenhouse gases. Landfill leakage also results in land and groundwater contamination.
As a response to both economic and environmental impacts, Australia is in desperate need of a more sustainable waste management strategy. At the same time, the over-reliance on fossil fuels for energy generation by implementing innovative technologies and facilitating renewable energy sources is also becoming crucial than ever in this scenario.
Ongoing waste recycling crisis in Australia
Australia has been reliant on sending most of the waste straight to landfill or overseas, to countries such as China, Indonesia and Vietnam. Now that China recently banned recycling imports from Australia, the new waste crisis has been precipitated.
Most of the states and councils have been struggling with waste management since the waste import restrictions exclude on average 99% of the recyclables that Australia used to trade in China. But why?
Australia has limited local opportunities for household and industrial recyclables. Losing the market overseas (China) for almost a third of these recycles like paper, glass and plastics have sent shockwaves through the global recycling market. Oversupply has caused the average price of these recyclables like paper scrap to fall from around AU$124 to A$0 per tonne!! In the process of minimizing the dissipation, Australian authorities have been reportedly stockpiling recyclable materials and putting into landfill for the longest period of time.
Recycling and WtE
There is an ongoing discussion regarding effective waste incineration and overall waste management in Australia.
With 40% of the total municipal waste being landfilled in the country, retaining the most value of the waste materials in the economy and reducing the natural resource depletion has been essential now. In a sustainable society based on circular economy thinking, landfills have no role to play.
According to the EU Framework Directive for waste, efficient energy recovery through WtE technology is to be regarded as the top of the waste hierarchy as long as possible- to mitigate climate change.
So, we can draw a conclusion with a note that- WtE is the most sustainable waste management technology that doesn't dismiss waste recycling or reusing. Rather, it makes the most value of waste materials, when they are no longer suitable for recycling but still capable of power and heat production. As a responsible citizen, you can also be a part of this renewable energy process, by letting the professional waste recycling and disposal service handle your organic or municipal waste.