The procedure has been tested since March and will be in full swing next week: Rhein-Sieg Waste Management Company (RSAG) is introducing a detection system to scan organic waste on some of its refuse collection vehicles. "We have to combat the ongoing contamination of organic waste bins. Because many bins of waste have items that do not belong there and damage the subsequent composting process," said RSAG Managing Director Ludgera Decking, explaining the procedure. With Rita Hoster, responsible for sales and the quality of the organic compost, and Sascha van Keeken, authorized signatory, Decking presented the new control system on Thursday at the RSAG plant in Troisdorf.

Plastic waste, glass, aluminium cans and normal garbage increasingly end up in the organic waste bins, which leads to a considerable loss of compost quality and additional costs for further sorting and disposal measures. It costs RSAG 300,000 euros a year to clean the organic waste of so-called impurities. This is done by hand after initial screening. Three employees are constantly working on sorting the organic waste on the conveyor belt for the smallest pieces of glass, metal or plastic. After the composting process, everything is sifted again, but micro-plastics still end up there - and thus in the food chain.

With the finest sensor technology, the "cheaters" are now to be tracked down. The technology (cost per vehicle: 60,000 euros) is mounted on the collection vehicle. It is hardly noticeable because it looks like a protective plate. The garbage workers can usually only check the upper garbage can area by having a look through, but with this sensor the entire garbage can content is checked by magnetic field. The measurement technology checks the contents in a similar way a person is checked at airport security. The technology emits a signal tone and suspends the lifting control when it finds something that doesn’t belong.

The detector electronics not only detects ferromagnetic materials, but also non-ferrous metals such as aluminium, lead, chromium, copper or nickel. The system can detect not only tin cans, aluminum-coated Tetra Paks, metal-containing coffee pads and lids of yoghurt containers, but also printed foils and plastic bags, energy-saving lamps, batteries, small electrical appliances and other problematic materials.

If there is even the smallest impurity in the bin, it is marked with a red sticker and left standing. The bin is not emptied. The customer must re-sort the bin himself and wait until the next time it is emptied - or dispose of the entire contents as household waste for a fee.

Households in Sankt Augustin, Niederkassel and Troisdorf had already been informed in writing, in the remaining municipalities this will gradually happen in the near future, according to van Keeken.

Out of 138,000 containers emptied in Rhine Sieg, only four percent are "contaminated". "That's still too much," says Hoster, referring to the positive experiences of other municipalities. In Euskirchen, the process led to a reduction in the contamination of organic waste from five to two percent, in Reutlingen even from six to 0.3 percent. (Orig. text: Dylan Cem Akalin, Translation: ck)