The city already has a high waste separation rate, but the focus is now shifting to waste prevention and reuse, according to Janko Kremžar, the boss of the municipal waste utility Snaga.

The city has done a lot over the years to increase waste separation and is now the leader among European capitals with a separation rate of close to 65%. "The strategic goal is to achieve an 80% share by 2030," he said.

The new waste processing facility, a EUR 150m project, is "the final stone in the mosaic which rounds off the system of waste processing in Ljubljana."

The centre, which will treat waste generated in Ljubljana and dozens of surrounding municipalities, has a facility for anaerobic treatment of organic waste, which reduces emissions and generates biogas. The final product of the treatment process is compost.

Despite the cutting-edge technology, waste separation and processing is still considered an "old" way to treat waste. Snaga is already focusing on waste prevention and reuse.

"Two years ago we decided to direct our information campaigns and user-focused activities to what the priority is...In general we are trying to give precedence to an issue that is simple, though ways of tackling it are not: do we really buy things that we need."

This issue is inextricably linked to "responsible consumerism, sustainable actions," said Kramžar, noting that Snaga has joined forces with what he describes as "natural allies": fellow waste utilities and green NGOs.

Snaga has for example launched campaigns promoting reuse and responsible use of food. A reuse centre, where old items such as furniture and home furnishings are renovated, has performed well too.

Kremžar noted that other cities are starting to take note. "There is increasing interest in Ljubljana sharing its experience with other European cities. There are delegations coming to Ljubljana and we are invited to congresses and conferences."

Waste treatment is also one of the areas that was evaluated when Ljubljana was vying for the title of Green Capital of Europe, which it holds this year. "It is our pleasure that we have helped win Ljubljana this prestigious title," Kremžar said.