While many cities struggle with environmentally destructive landfills, Vienna has created one that is in many respects a net-positive for the environment. It’s called Rautenweg, and its success has resulted from several decades of progressive urban waste policy. In response to steep increases in waste during the 1960s, Vienna started incinerating its trash, and channelling the heat generated into the city’s district heating system. Today, the controlled burning process in the city’s four incinerators reduces Vienna’s waste to about 10% of its original volume, providing heating and hot water for about 400,000 homes. 

Perhaps just as interesting is that the residual waste which is sent to Rautenweg is disposed of in a way that looks and feels green and natural. This unique landscape started to take shape in 2009, when ash and slag from non-recyclable waste was mixed with sand, water and cement make concrete – about 200,000 tonnes each year. The concrete is used to create stable terraces in the landfill. Three meters of soil are added on top of each terrace, and growth of the local plants and trees is encouraged. This has resulted in a lush green hill that is 40 meters high, and slated to grow another 35 meters by 2065. 

The site’s tranquil appearance belies the complex and innovative technical work that goes into creating and maintaining it. For instance, there are 140 bright yellow gas wells that harvest methane created by buried waste which was disposed before there was recycling. This gas is turned into electricity and sent into the city’s grid, providing power for around 1,000 households. In the 1980s, contamination of surrounding groundwater from the landfill prompted the development of an innovation known as the “Viennese Chamber System”. The landfill was surrounded by two rings of leak-proof walls extending 40 meters into the ground and separated into 49 chambers with water pumps, so the water level inside the landfill cannot spill into the surrounding water table.