Perfect blend

boston's Logan Airport in the us now has cleaner buses to transport passengers. These shuttle buses are designed to run on a blend consisting of 80 per cent diesel and 20 per cent 'biodiesel' -- vegetable oil or grease that can be recycled from fast food chains. Apart from providing an alternative to pure diesel, the fuel called b-20 improves air quality by significantly cutting down emissions of carbon monoxide, particulates and hydrocarbons by 20-40 per cent.

"It allows older diesel engines to comply with the environmental regulations which is an important advantage," says James Ricci, president of Twin Rivers Technologies, a company that is based in Massachusetts, us, and manufactures biofuel additives. The alternative to old engines is rebuilding them or buying new buses that are very expensive. Ricci says that there are no drawbacks to his company's product, except for a little French-fry odour which is hardly the worst thing in the world.

Massport, the company that operates Logan Airport, is so enthusiastic about the new concept of 'biodiesel' that it plans to run some of its 200 trucks on biodiesel. "From an operational point of view, b-20 fuel is not very different from the regular diesel," says Doug Wheaton, Massport's alternative fuel manager. "No infrastructure changes are required, which makes for a seamless transition. And above all, it saves pure diesel," he adds.