Wastewater Warms Cold Commuters at Bus Terminal



Blue Kolding

Photo by Maria Tuxen Hedegaard.



Photo by DANISH™


Blue Kolding

Photo by DANISH™



Photo by Maria Tuxen Hedegaard


Wastewater is a resource that the citizens and commuters of Kolding seem to embrace. The local energy company BlueKolding A/S who are running the project Powered By You is heating the benches of central bus terminal in Kolding with wastewater. And it doesn’t stop there.

Denmark is a cold and windy place in the winter especially when waiting for the bus to arrive. And though many danes are loyal users of public transportation, a bus stop can be a cold and hostile place. On a frosty morning the icecold wind from north will surround the steadfast commuter on the way to work, which can cause both a flue and a grumpy mood. But not anymore – In Kolding bus stops are now the place you go for warmth – like a firery oilbarrel in the cold wind, this bus terminal is a place where you seek shelter from the Danish winter.

“Wastewater is like crude oil to us. Many people see it as waste that we pour out in to the sewer but that is a misunderstanding. Wastewater is a resource that can create energy and heat, that’s wat we do”, says Per Holm, who is CEO at BlueKolding A/S and in charge of the project Powered By You.

It all started at a Design Camp in 2014 arranged by Design School Kolding, where students and businesses work together to solve a problem that the businesses have. Blue Kolding A/S wanted to prove how wastewater is actually a real resource, and not just a costly problem. Per Holm worked with design student Birkir Gudmundsson, who challenged him to think outside the box.

“When I was talking about water as a resource that can produce energy and heating, Birkir said that two of the coldest places he knew of where train stations and bus terminals. Therefor we came up with a way to heat the benches in the local bus terminal from wastewater. A sustainable solution to a very concrete problem”, Per Holm, says.

BlueKolding A/S is now heating the benches of Koldings most central bus terminal with wastewater that would have ended up in the ocean. The wastewater is heated in a pump next to the terminal, and lead into the back of the benches, like a radiator. BlueKolding has later used the same technology to heat an entire building with 83 student homes from wastewater. In 2017 that project won Danish Design Award for best clean solution, showing the potential that wastewater has.

“The student homes are about to be expanded to double size which we are also going to heat with wastewater. And our analysis shows a potential to heat around 1200 households in the local area”, Per Holm, finishes.

The potential and the ideas to put wastewater to good use are there. Who knows what the future is going to bring? Per Holm doesn’t rule out anything.

You can read more about Blue Kolding here.


The goal of DANISH™ is to promote Danish architecture and design in a broad perspective, and demonstrate all the potentials in these fields.

Read our story