May 2 2008
Recycling has been around for ages, but it wasn't until the 1970s that drop-off recycling centres emerged, and the late 1980s that doorstep collection began. While the existing recycling process is crucial to dealing with the growing amount of waste we produce, researchers are looking for alternative solutions.
A group from Spain, Latvia and Lithuania says it is now ready to launch a green solution for plastic waste management for the European market. Funded by the EUREKA programme, the SANDPLAST project has developed a technology for the production of concrete building materials using polymer waste and inert fillers.
Everyday, we throw away large quantities of polymer in the form of plastic bottles, cartons and yoghurt pots. Experts estimate that 25% of polymer waste is unsuitable for recycling for three main reasons: it contains mixtures of different types of polymers; it is economically unprofitable; and it is too dirty.
Now, researchers from the Latvian Technological Centre, and the Institute of Polymer Mechanics at the University of Latvia have come up with a solution. Working with Hormigones Uniland, a Spanish cement company, the researchers have succeeded in turning thermoplastic polymer waste into a binding substance that could be mixed with other materials, like sand, to generate cement-free polymer concrete goods.
'The polymer concrete bricks look like ordinary bricks made from cement,' says Dr Juris Balodis, project manager at the Latvian Technological Centre. However, he points out that the polymer concrete absorbs less water, 'so it is very good for resisting temperature variations like freezing'. Both the European market and consumers are expected to benefit from this material, which can work well in a wide range of products, including street furniture and street curbs.
Dr Balodis and his team are now researching how to accelerate the production of bricks. The current rate is three bricks per minute, but the team wants to increase production to between 30 and 60 bricks per minute.
Convinced of the commercial potential of the technique he helped to design in the project, researcher Valdis Leitlands has since launched Partneris L.V., a spin-off company to develop new building products from polymer waste. The company has joined forces with Hormigones Uniland, which has the capacity to produce two million cubic metres of ready-mix concrete each year, to help with testing products developed from the technique and to identify markets. Lithuanian partners are also taking part in the project.
'Because Latvia is a small country, it is important to us to explore markets abroad. The Spanish partner knows the markets well,' explains Dr Balodis.
The researchers believe these innovative bricks will be less expensive than the traditional bricks. They will also prove beneficial for the environment because polymer waste processing could become economically profitable. Key customers, according to the project partners, would be waste management companies and firms that produce large amounts of polymer waste.
To date, the project partners have applied the technology in Latvia to make polymer concrete pavement bricks, and a form of light-weight concrete in Lithuania.