New Plant Turns Waste Into Building Blocks

New Plant Turns Waste Into Building Blocks

A pilot plant to turn waste into building materials has begun at the University of East London. The research plant will produce lightweight aggregates from incinerator bottom ash, dredge sludge and sewage, and will run on energy generated from the waste.

Funded by a Landfill Tax Credit grant of £400,000 from the RMC Environment Fund, the industrial scale plant based in Barking will act as a research center for engineers to develop designer aggregates from waste material. Run by the university’s School of Computing and Technology, the plant, known as the Manufactured Aggregate Research Centre (MARC), has the latest thermal processing techniques and uses energy produced by the waste to ‘roast’ materials into coated pellets destined for the construction industry.

“The gases in the heated raw materials roast from the inside out, creating a self-coating pellet rather like a Malteser,” says Project Manager Darryl Newport. “The beauty of this process is that it takes waste that would otherwise go to landfill, and using energy in the sewage, turns it into useful building materials that would otherwise have to be quarried. For the environment, it is a win-win-win situation.”

UEL staff have already begun trials on experimental batches of pelletised aggregate produced by MARC, which has a ‘Trefoil’ kiln shaped like a three-leaf clover to create an even cascade of pellets. Dr Paul Smith, Head of the School of Computing and Technology says “We are testing pellets for strength and durability in various construction applications, and looking at optimising the mix of raw materials for specific outputs.”

“If this technology were to be adopted on an industrial level, the amount of waste going to landfill in the UK could potentially be cut by up to 70%,” says Darryl Newport. “This would also require development of thermal separation systems to sort Municipal Solid Waste. If ten to fifteen full scale plants were to be located close to big cities, this would significantly cut down on the transport costs of haulage, which is also detrimental to the environment, and could contribute up to 10% of aggregate production for the UK market.”

A recent report by Environment Agency indicated that bottom ash from incinerators poses no significant health risk and could potentially be a valuable secondary aggregate.