We use a huge amount of single-use plastic each year － we buy one million plastic bottles each minute around the world. Plastic waste, a material that can take centuries or more to disappear, is causing irreparable damage to the planet. However, plastic waste generated in many countries typically ends up in open, uncontrolled landfills (垃圾填埋池) － most of which eventually enters the ocean either transported by wind or through waterways.
Now, Nzambi Matee, a 29-year-old woman from Nairobi, Kenya, is dealing with this global crisis by recycling bags, containers, and other waste products into bricks used for construction projects. Before launching her company, Gjenge Makers, Matee worked as an oil-industry engineer. After encountering plastic waste along Nairobi's streets, she decided to quit her job and created a small lab, testing sand and plastic combinations. Matee eventually received a scholarship to study in the materials lab at the University of Colorado Boulder, where she ultimately developed a prototype (原型) for the machine that now produces the new bricks.
Made from a combination of plastic and sand, the bricks have a melting point higher than 350℃ and are more durable than concrete bricks. Matee and her team source much of the raw product from factories and recyclers, and sometimes it's free, which allows the company to reduce the price point on the product and make it more affordable for schools and homeowners.
"There is that waste recyclers cannot process anymore. That is what we get," Matee said. Her factory produces 1,500 bricks each day, made from a mix of different kinds of plastic. These are high-density polyethylene, used in milk and shampoo bottles; low-density polyethylene, often used for sandwich bags; and polypropylene, often used for ropes. But she does not work with polyethylene terephthalate or PET, commonly used for plastic bottles, which can be made into the same form easily again and again.
The plastic waste is mixed with sand, heated and then pressed into bricks, which are sold at varying prices, depending on thickness and colour.
