Published article in Bauwelt Magazine number 13 on June 21st 2024
Interviewer: Hanna Sturm

For over fifty years the Swedish company Envac has been manufacturing pneumatic systems that transport garbage bags through pipes underground to a collection point. The promise: more cleanliness, less traffic, less environmental pollution. Mattias Widell, Head of Strategy and Business Development Envac North Europe, explains how the system has developed since the 1960s – and how it can also be implemented in Europe’s old cities.

Envac has been supplying public buildings such as hospitals and residential complexes with pneumatic systems since the 1960s, but now also entire cities, such as Bergen in Norway. How do you manage to implement complex systems with many kilometers of pipes in a historical area?
In the 1960’s and 1970’s, we mainly equipped new buildings with pneumatic systems. As the construction industry declined, we began to focus more on implementing them in existing buildings where other networks of pipes were already in place. Bergen is an old city with narrow, cobbled streets and many hills. At first glance, you might think that it is impossible to create a comprehensive pipe network there. But driving large garbage trucks through the narrow streets is not easy either. Fire protection was also an important argument for Bergen, as there had been an increasing number of fires in garbage bins and the city wanted to protect its historic wooden houses. The city was very clever in its implementation and founded the “Digging Club”, an institution that coordinates all infrastructure companies when a street has to be opened for pipe laying. Then, for example, the water and electricity companies are also asked whether they need repairs, and everything is repaired in one go. So, street by street, not only were the vacuum system and district heating installed, but the infrastructure was also repaired at the same time.

Germany relies almost exclusively on conventional garbage bins for waste disposal. There were many pioneering pneumatic system projects in the 1970’s. One of the first systems in Germany from Envac, back then called “Centralsug”, was installed in Munich’s Olympic Village in 1972. After 45 years of operation, the system was shut down in 2017. How has the system evolved since then?
When waste separation was introduced in Germany in the 1980’s, we had not yet integrated it into the system, including in Munich’s Olympic Village. The technology has evolved enormously since then. The pipes and fans were much larger than necessary back then. We worked on using less material and making the system more energy efficient. For example, the pneumatic system is only activated when a certain amount of garbage has collected at the end of a pipe, whereas the old system always emptied all the pipes at once, which required much more energy.

The reason for the closure in Munich was the improper disposal of bulky and hazardous waste, which repeatedly led to blockages. This anonymous form of waste disposal lacks social control by neighbors or caretakers. What options are there for waste separation, and how can incorrect disposal be reduced?
While in the past many people did not even know that they were using a pneumatic system, today we provide information on how to use the system properly. In addition, the openings of the pipes are designed so that no bulky objects can be inserted that could lead to blockages.

As far as incorrect disposal goes, our experience has shown that the easier the separation of waste is, the fewer the number of incorrect disposals. There are two different systems for waste separation. The first has several inlets for different types of waste inside and outside the building. The waste arrives sorted at a collection facility, where it is separated from the bags, cleaned and picked up by garbage trucks.

In the second system, users separate the garbage into different colored bags, which are then thrown together into one pipe and optically sorted in a central garbage facility. The pneumatic system of the optical sorting system is much more efficient and costs less, but also requires the sorting system. However, this has the advantage that it can also sort conventionally collected garbage into different colored bags, which then also only requires one container – which saves the garbage collectors costs on vehicles and shorter travel times.

One argument against renovating the system in Munich was the damage caused to the trees that had grown during the operating period by opening up the streets. How can changes in the environment be taken into account when renewing the system?
Today, when new systems are installed, they are in the middle of the street and not near the trees on the side of the road. Unfortunately, this cannot be changed with old systems. If water pipes are damaged, a repair layer can be placed inside the old pipes. However, since we need very stable pipes, there is no comparable solution for our system. Instead of digging them out in a way that protects the roots, it is usually easier to leave the old pipes under the trees and lay new ones in the middle of the street. The old pipes can be filled with sand or concrete via inspection openings to prevent damage caused by subsidence.

Why should a municipality integrate your system into the existing city?
Implementing a vacuum system into existing buildings is complex, but it can significantly improve the quality of life in cities. There is less noise and particle pollution from garbage collection and less odor nuisance. Since the Covid-19 pandemic, hygiene has also become a major issue. In addition, conventional garbage collection takes up a lot of space. You need several containers and wide streets for maneuvering large garbage trucks. With a garbage collection point on the edge of the residential area, the freed-up street space can be used for outdoor areas of restaurants and shops, playgrounds or urban greenery.

Do vacuum systems also make sense in rural areas?
The vacuum system is only effective above a certain population density and is generally not suitable for rural areas. However, the optical sorting system with the different colored garbage bags works particularly well there. The garbage trucks have large areas of operation in rural areas, so the transport effort is significantly reduced if they only have to drive once instead of four times. And it is also easier for rural residents to throw all the garbage into one container.

In the architectural discourse, after the “smart home”, there is a return to robust and simple buildings. The “grey energy” of a building, which is necessary for its construction and maintenance, plays an important role. Does Envac account for the total energy required for the production, installation, maintenance and deinstallation of the system (pipelines and central units)? If so, how does this compare to conventional waste disposal?
Studies show that comparisons between conventional and vacuum systems vary greatly when it comes to the CO2 balance. This is because the most important factor in vacuum systems is the 90 percent reduction in transport routes for waste collection. Depending on whether the garbage trucks are powered by diesel, biogas or electric motors, the CO2 balance can therefore be very different. This year’s sustainability report will focus on the environmental impact of our system. For example, the question of steel production and other manufacturing conditions of the pipe network. But it is also crucial to make the operation of the system and the energy used to operate it more efficient.

Envac promises cleaner and more environmentally friendly waste disposal in cities. How is the system more environmentally friendly than conventional waste disposal?
The biggest factor is the aforementioned reduction in traffic and the associated CO2 emissions. We are also working on solutions for intelligent waste separation so that as little waste as possible has to be incinerated in the end. To do this, we must create incentives to separate waste properly on the one hand, and find solutions for the waste that is not separated on the other. One vision is to combine our optical sorting system with an infrared sorting system that removes different types of plastic and metals from the unsorted residual waste before it is incinerated. Another major ecological advantage is the space savings,
which, for example, enables green spaces instead of waste sites.

Your “WasteSmart system” is a flagship project of the EU “Smart City” initiative, which is being implemented in cities such as Stockholm, Barcelona and Cologne. What is behind the system?
The “WasteSmart system” improves the optical sorting system using intelligent technology. The chute recognizes the colors of the garbage bags and checks their volume and weight. These values ​​tell us how well the garbage has been separated. Since all users register in advance, we can give them feedback via an app. Such incentives have a positive effect on garbage separation, so that less waste has to be burned. In some cities, the option of our “pay-as-you-throw” system is also being tested, where users pay according to the quality of recycling.

What other developments are you currently working on?
We are in the process of developing a digital platform that provides a bigger picture of waste disposal and cycles. It will not only provide information about the vacuum system, but also about collection points for bulky waste or exchange offers for raw materials in the neighborhood. This holistic concept also includes seeing the large terminals for waste collection and sorting not just as industrial buildings, but also as public places where the “urban metabolism” can be experienced. In Sweden, we have opened the first terminals for visitors. There are repair workshops and public tours, and school classes come by to learn about recycling.

Full article in German on Bauwelt website
(Vollständiger Artikel auf Deutsch auf der Bauwelt-Website).

Full article in German in downloadable PDF
(Vollständiger Artikel auf Deutsch als herunterladbares PDF).

Press Contact:

Mattias Widell
Head of Strategy and Business Development
Envac North Europe