University of Cambridge

Bottle Brick – University of Cambridge, Student Design Project



Bottle Brick – the small-scale community PET bottle recycling solution. It recycles and reforms waste plastic bottles into building bricks for the developing world, eliminating use of concrete and reducing landfill waste.

Bottle Brick introduces a novel process of reforming a waste PET drinks bottle into a stackable, interlocking, tessellating shape which may be used as a structural brick. We identified an existing practice in some developing world countries such as Nicaragua and Nigeria whereby bottles are removed from local landfill sites, filled with mud and stacked as building blocks, held together with mortar. The result is a robust housing structure. Having seen this we questioned how the process might be improved. We set ourselves the challenge of making this production process cheaper, easier and even more environmentally friendly. The existing ‘bottle wall’ requires at least 25% concrete in volume. Not only is concrete expensive, it is non-renewable, non-recyclable and its manufacture contributes to 5% of global CO2 emissions. And so we sought to minimise or eliminate the use of concrete.

We have developed a vessel for the process of heating and blow moulding a bottle at 14 bar through manual labour with the use of a bicycle pump and then cooling the bottle. The output is a well-defined, intricate brick which successfully stacks in a honeycomb formation, significantly reducing the required volume of concrete. The working prototype successfully provides ‘proof of concept’ and is designed to be easily scalable in order to produce bottles in larger quantities. The rate of production of one bottle is 6 minutes. Scaling to 10 units would allow a rate of production of 100 bottles per hour.

Our organisation would be run as a not-for-profit social enterprise, distributing this product through existing charitable organisations to areas which may benefit from this practice. To our knowledge there is currently no other company which recycles bottles by directly re-blow-moulding them, making this project a worthwhile venture in its own right.

Team: Ruby Gunn, Tom Parker, Laurel Townsend.

More information: http://www.ifm.eng.cam.ac.uk/education/met/a/design/design-show-2016/

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