Waste that would otherwise be dumped into our shrinking landfill sites will be transformed into paving bricks and blocks The waste-intensive construction industry is to be asked to buy back the rubble it discards - in the form of environmentally friendly building material. Paving bricks and blocks made from recycled construction waste are about to be produced commercially in Hong Kong. The Polytechnic University, which developed the technology, is set to sign its first licensing agreement with a manufacturer tomorrow. The environmentally friendly building blocks have been patented in Britain and will be produced by K. Wah Construction Material, one of the five main local suppliers of construction materials. Research team leader Poon Chi-sun, a professor in the university's department of civil and structural engineering, said the bricks had the potential to remove 'a large percentage' of granular construction waste that would otherwise end up in landfill sites. 'Our main target is to turn waste into a resource. We produce a lot of construction and demolition waste in Hong Kong every day and we cannot accommodate it, especially now that some large reclamation projects have been stopped,' he said. According to the Environmental Protection Department, more than 10,000 tonnes of construction and demolition waste was dumped in landfill sites every day last year, with a further 35,000 tonnes diverted for use in reclamation and site-formation projects. A senior Environment, Works and Transport Bureau official previously said that if waste reduction targets were not met and material not disposed of in reclamation projects, Hong Kong could expect to run out of landfill space in as little as five years. The technology to turn waste into bricks was developed last year and road-tested as paving stones over the past 12 months in a number of high-traffic pedestrian areas, including the Housing Authority's Oi Man Estate in Ho Man Tin, Cheung Sha Wan Road, West Rail's Kam Tin station and a primary school in Yuen Long. 'We used the bricks in practical sites and monitored [their performance] for one year. It seems comparable to normal bricks,' said Professor Poon, adding that the cost was comparable to conventional bricks. The blocks were designed for use in pedestrian walkways and potentially in wall partitions, but were not suitable for structural walls, he said. They are able to absorb up to 80 to 85 per cent of inert waste material such as concrete rubble, tiles, glass and bricks, with a maximum of 5 per cent of other materials such as plastic. Ash and other waste material from coal-fired power plants can also be incorporated. As an added environmental feature, the researchers have developed a paving block that can remove low concentrations of air pollutants such as nitrogen oxides through a chemical reaction triggered by sunlight. The new building materials are entering the market at a crucial time. Construction waste accounted for almost half of the 21,158 tonnes of solid waste disposed at landfill sites on a daily basis last year and, with many reclamation projects on hold, this figure is expected to increase dramatically. To reduce waste, the government is proposing a three-tier structure for landfill charges, including a $125-per-tonne charge for construction waste from next year.