An overflowing waste bin in a park: pizza boxes piled up, coffee cups, napkins and beer cans on the ground. Cities all over Europe have been fighting against such a deluge of waste for years. Corona exacerbates the problem because people spend more time outdoors. “With classic rubbish bins, waste management in most cities is now reaching its limits. Many metropolitan areas in Finland, for example, had to empty public waste bins up to four times a day even before the pandemic,” said Antti Kinnunen, marketing manager at Finbin. The Finnish company’s answer: a waste bin called CitySolar, which compresses waste and thereby has a much higher capacity. A waste bin that is connected to the Internet and triggers an emptying before reaching the maximum fill level. “With CitySolar, we are making a contribution to reducing disagreeable waste scenes in cities and improving the CO2 balance in waste management. Up to four out of five trips can be avoided with the networked waste bin,” Kinnunen added.

Less emptying: solar-powered compactor compresses waste Visually, CitySolar is reminiscent of the robot R2-D2 from Star Wars—only somewhat larger, more angular and less noisy. Its operation is simple: a passer-by opens the waste flap by hand or by foot. Once the flap has closed, an electric press compresses the waste. It is done so effectively that a container with a capacity of 240 liters can hold 1,500 liters of waste—with a total weight of up to 600 kilograms. The waste bin can do this work anywhere, independent of the public power grid. Because the engineers have installed solar panels on the roof. In addition, a lithium-ion battery that stores power for cloudy periods and the night. This means that energy is available for the waste compactor around the clock. Indoors, CitySolar is not dependent on solar energy. The waste bin can be connected to the conventional power grid here.

Maintenance-free components 

To increase the sustainability of the novel waste bins further, the engineers have made every effort to use components that do not require maintenance. After all, every maintenance operation causes CO2 emissions—solely through travel to the site. Finding such components was not always easy. An example: the plain bearings for the mechanics of the press and the skirting board. Classic bearings made of metal were out of the question for the job. Why? First, because there would be a risk of corrosion with high humidity. Second, because the lubrication of metal bearings can lead to several problems. It would combine with dust and dirt and, over time, become a paste that reduces the bearing’s sliding ability, making the system less smooth and, in the worst case, leading to failure. To avoid these problems, the engineers set out to find lubrication-free plain bearings made of high-performance plastic. “We looked at bearings from different manufacturers thoroughly,” Kinnunen recalled. “Durability and reliability were the main criteria and the reason why we chose plain bearings from igus.