Waste is a burning issue

Residual waste that cannot be recycled should be used as an energy source rather than going to landfill, says Rolf Stein.

The UK government is legally committed to achieving the binding target of 50 per cent recycling levels by 2020, thereby reducing the amount of waste we send to landfill.
Central government and local councils in England have invested heavily in reaching this recycling target over the past ten years. However, according to the latest figures from the Department for Environment, Food and Rural Affairs (Defra) released in November 2013, we have begun to reach the limit of our capacity for recycling. It is thus imperative that we devise a sustainable strategy to maximise landfill diversion for waste that cannot be recycled.
Defra’s figures reveal that the drive to increase recycling has been very successful across England, with household recycling rates increasing from 11 per cent to 40 per cent between 2000 and 2010. The drivers have been increases in landfill tax and the wider availability of recycling centres.
However, there is a wide variance in recycling rates across the country. Some councils, such as Ashford in Kent, achieved only 12 per cent, while Rochford District Council in Essex hit 67 per cent.
Rochford is testimony to how effective Defra’s policies have been in increasing recycling. However, the government has withdrawn funding for recycling schemes because of extreme pressures on the public purse, and last year recycling increased by only 0.2 per cent nationally.
The cutbacks come at a pivotal time in the push towards realising the 2020 target of 50 per cent recycling and Defra concedes that it is now going to be very hard to meet this target. A sustainable means for disposing of waste is therefore all the more important.
Taxes have been successful in diverting waste from landfill, where it can emit greenhouse gas and be highly damaging to the environment. As a result, incineration rates have risen by 13 per cent. Modern waste incineration involves large-scale burning of waste, where a portion of the energy released is recovered to produce steam, which in turn is used for power generation. Traditionally, incinerators have been only 15-20 per cent efficient, but with increased steam pressures and temperatures, these systems are now able to deliver 20-25 per cent efficiency.
Unfortunately, this efficiency has been achieved only with the use of very expensive corrosion-resistant metals in the boilers. Additionally, around 20 per cent by mass of what is fed into the plants ends up as ash, which is eventually disposed of as an aggregate material but first has to undergo considerable “weathering” to leach out heavy metals and other contaminants.
Furthermore, these incinerator facilities require large amounts of waste to make them economically viable. Some argue that this encourages the burning of waste that could otherwise be recycled.
There is, however, an alternative. With the latest, most efficient technologies, there is the potential to take residual household and commercial waste and turn it into clean, sustainable energy, be that in the form of electrical power and heat or fuels such as syngas, hydrogen or substitute natural gas.
Advanced conversion technologies can transform solid waste into an energy-rich synthesis gas (syngas). Gasification and plasma conversion can be used to convert municipal and commercial waste into highly efficient fuel and energy sources, while minimising visual and environmental impacts.
The process also turns the ash residues associated with incineration into a stable vitrified product that has multiple practical applications. When coupled with recycling strategies, this technology has the potential to allow for near complete landfill diversion.
Instead of viewing waste as a problem that needs to be disposed of, we need to consider is as a resource. There is enormous potential for advanced energy-from-waste plants to simultaneously help solve waste management problems and help the UK meet its 2020 European renewable energy targets, all by turning residential and commercial waste into a clean, sustainable energy source.