The waste hierarchy is a tool that defines waste management strategies in terms of their desirability and environmental impact.
The Waste Hierarchy
The world and the Waste Hierarchy
In order to illustrate how “energy recovery” fits into the global waste management structure, it’s important to understand our current situation.
The following data was obtained from the World Bank Report “What a Waste: A Global Review of Solid Waste Management” , which was published in March 2012 using data collected in 2009.
Globally, urban residents produced nearly 700 million tonnes of solid waste in 1999. By 2009 this had increased to 1.3 billion tonnes. To put that into perspective that’s 1.2 kilograms of waste per day. That was an increase of 0.56 kg per day or 82% from 1999. The increase is largely as a result of movement into urban areas, sustained economic growth and the associated consumption as incomes grow.
Australia and in many places around the world has been far more successful at reusing waste water than solid waste. Our water reuse has steadily grown but opportunities to simply reuse solid waste items are limited particularly due to health concerns and a more affluent society.
Recycling rates vary widely globally with some developed countries achieving greater than 50%, however many countries have very low rates of recycling with the majority of waste still going to landfill. Interestingly, European countries with the highest penetration of Waste to Energy also have the highest recycling rates. Although Australia’s recycling rate at 52% (2006/07) is pretty good by world standards it has only slightly increased from 1999 levels. That’s because 91% of Australian households already recycle but there is a limit to what can be recycled.
4. Recover Energy
While there is virtually no energy recovery in Australia, with this segment of the waste hierarchy representing only 1% of waste management, globally waste to energy accounts for 16% of waste management. At this stage in Australia, landfill gas capture and anaerobic digestion of waste are the only significant forms of energy recovery practiced.
Australia like the rest of the world is still heavily reliant on the least sustainable strategy for waste management – landfill disposal. Between 2001 and 2007, the volume of waste to landfill increased by 12%, despite Government efforts to encourage waste reduction and waste diversion through recycling and alternative waste treatment technologies. In all, 21.3 million tonnes of waste was dumped in landfills in Australia in 2007. Globally, 700 million tonnes went to landfill in 2009 which is almost double the amount in 1999.
Why Energy Recovery or Waste to Energy is needed for Sustainable Waste Management
It’s important to point out that Energy Recovery is not the total or sole solution for waste management in Australia or the world. However, the statistics above show three inconvenient truths about our behaviour and waste management. They are:
- We are an increasingly wasteful society. Reducing waste volume is the most effective and sustainable action but we are not doing this.
- Recycling is vital but not everything can be recycled. There will always be residual waste items that need to be managed after recycling has been optimised.
- Landfilling is still increasing despite our best efforts.
These three facts prove there is a need for clean energy recovery processes from waste. We can’t keep burying our waste in landfills and ignoring the associated long term environmental liabilities being created. Clean energy recovery processes like gasification are vital to accelerate our landfill diversion performance and our progress towards a Zero Landfill society. With appropriate environmental conditions, energy recovery plants can safely generate renewable energy with minimal environmental impact, as has been proven in many other developed countries in the world. In fact it has been shown that countries that adopt energy recovery also have the highest rates of recycling in the world.
In summary, we need clean energy recovery systems to achieve sustainable waste management, progress towards a Zero Landfill society and help reduce our dependence on energy derived from fossil fuels.