Pilot project treats waste to limit need for landfill

The pyrolosysis plant at Palm Jumeirah, which processes six tons of waste a day.

A small-scale power station on The Palm Jumeirah which produces energy while processing waste material could be a way to avert the country's mounting landfill and electricity problems, the company behind the project said. The facility, which handles six tonnes of waste per day, is the first of its kind in the Middle East. Built by Enviro-Resources for the developer Nakheel, it handles all the waste from a labour camp for 500 men as well as some household and industrial rubbish.

The plant uses a process called pyrolysis, which produces hydrogen, carbon dioxide and a solid substance called "carbon char" - weighing five to 10 per cent of the original waste. The process cuts the need for landfill and produces power for a nearby workshop, while the char can be sold for industrial purposes. Every day, 8,500 to 10,000 tonnes of waste reach Sharjah's main landfill. In Dubai, a total of 3.4 million tonnes of solid waste was collected throughout 2007. The figure, which translates to more than 9,000 tonnes per day, is expected to increase to 13,000 tonnes per day by 2010.

Abu Dhabi's biggest landfill, Al Dhafra, receives at least 20,000 tonnes a day. Landfill sites emit a large amount of greenhouse gases, mainly methane, as waste decomposes. "There is overuse of landfill," said David Mills, the chairman of Enviro-Resources. "It is so cheap here and there is no incentive for other solutions to be developed. In other countries there are serious landfill taxes and subsidies for plants like this one."

David Weaver, the company's chief executive, said that pyrolysis exposes compressed waste to heat, but in the absence of oxygen. Under pressure of superheated air, sometimes as hot as 1,100°C, the material disintegrates leaving carbon dioxide and hydrogen, which can be used as fuel. And because there is no combustion, pollution is less compared to a traditional incinerator. The char can also be sold for use in the production of paint, plastics and even medical applications.

"Before the credit crunch it was selling for £450 per tonne," Mr Weaver said. The char now sells for around £200 (Dh1,080) per tonne. "The whole process is about exposing the waste to heat in the absence of oxygen," he said. The Dubai plant is tiny compared with the projects Mr Weaver has installed in other parts of the world. But the plant's small size makes it ideal for developers who are compelled to operate diesel generators, as there is a limit to the amount of electricity the Dubai Water and Electricity Authority can provide.

Enviro-Resources has also introduced water-saving measures at the labour accommodation. Fifty waterless toilets have been installed, each saving 13,000 litres of water per month. The water that is used in the accommodation, in showers and sinks, for example, is recycled so that 15,000 litres of "grey" water are produced every day. Some of the water goes to the accommodation's staff laundry where more than 300 uniforms are washed every day. The water is also used in construction and for dust control.

"If 50,000 people in Dubai use grey water, this will save drinking water enough for a million people," Mr Mills said. [e-mail]