Aston University tackles changing landfill pile

Aston University’s Bio-Energy Research Group (BERG) and Biffa, one of the UK’s largest waste companies, have teamed up to find new ways to recover energy from a changing mix of domestic, commercial and industrial landfill waste.

The Government’s pledge to cut the amount of biodegradable waste going to landfill by 50% from 1995 levels by 2013 means UK landfill operators face a very different pile of rubbish than in the past.

Biffa operates over 30 landfill sites across the UK. Most of these sites recover landfill gas with more than 50% methane to power reciprocating engines that generate electricity for the national grid.

But with increasing amounts of biodegradable waste being diverted, the landfill mix is changing. The diminishing organic and moisture content of the waste, coupled with tighter regulations for new landfill sites, mean lower rates of waste decay and a decline in landfill gas production.

Converting the remaining fraction of organic waste into energy onsite is challenging but essential if the Government is going to meet its target to recover 67% of Britain’s waste by 2015.

An innovative conversion method called pyrolysis could provide the answer. Under one of three national CASE studentships awarded by the Mini-Waste Faraday Partnership, Biffa has teamed up with BERG, a leading research group at Aston University focusing on pyrolysis technology, to investigate converting the organic fraction of various waste streams into a gaseous or liquid fuel to power the existing engines.

Pyrolysis heats up biomass to high temperatures in the absence of oxygen. The technology can convert organic waste into gases or liquids for fuel after separating out valuable metals and other products, which can then be reused in building and construction materials.

BERG will characterise different waste streams, test them in its pyrolysis reactors and evaluate their potential to be used on landfill sites.

“Pyrolysis is a technology with promise. It offers an innovative way to recover energy from waste and reduce our dependence on fossil fuels” said Stamatios Dacey, the BERG PhD student who was awarded the CASE studentship.