We protect the environment

Metro construction projects are large and have a big impact on the surrounding environment. Therefore, there are strict requirements to ensure that the construction does not degrade the environment in a wide range of areas.

Metroselskabet is not usually tasked with making construction sites 'cleaner' than they were before we started our work, but we are committed to leaving the site in the same environmental condition as we received it, and it is our ambition to improve conditions wherever practical.

Long before the metro construction begins, the environmental conditions have been thoroughly analysed to ensure that the metro is built in the most environmentally friendly way.

By calculating material consumption and climate impact, along with assessing all other environmental aspects, we ensure that the final installation is as environmentally friendly as possible. Environmental considerations are already included in the first sketch projects and influence the choice of the final solution in all phases of the project. Prior to the final decision on a new project, an environmental assessment is carried out, which also involves the public through consultation processes and public meetings. The dialogue determines the best way to implement the project.

Once the metro construction is underway, we carry out environmental inspections on average once a month as the client at our metro construction sites. We do this to ensure that our contractor complies with the guidelines and requirements set by the authorities for construction projects, but also to optimise environmental considerations so that, in collaboration with our contractor, we can build the metro with the least possible negative impact on the surrounding environment. In addition to our client supervision, the contractor supervises the work itself, while the authorities also visit the construction sites to check conditions.

Environmental monitoring takes place physically, where contractors, site managers and our inspectors schedule a time to walk around the site and inspect the relevant processes. Some processes are also monitored via computerised systems, allowing both real-time measurements and data on environmental conditions over a longer period of time. This then forms the basis of the agenda for the physical site visits. Our experience shows that we get the best results when the contractor is prepared for the visit and we make sure that the environmental work is an ongoing collaboration.

One of the most important areas is waste management. There are municipal rules for waste management and sorting on construction sites, similar to what you would find in a household.

Soil should be sorted as a waste product - but a distinction is made between what has been dug in before and what is untouched and the degree of contamination. The transport of the soil is also important, so we make sure that no soil or calcareous muck (from the tunnel bores in the subsoil's limestone layer) is dropped from lorries that can make a mess on and off the construction site.

Other waste is also sorted in accordance with municipal regulations, where there are general categories such as hazardous chemical waste, wood, iron, concrete and plastic, with several subcategories to be handled in their own way. These specifications determine whether and how the waste materials can be recycled, incinerated or used in new ways.

Metroselskabet is working to improve waste sorting even further so that more of the waste can find a new use without being incinerated.

Metroselskabet has a strong focus on avoiding spillage of chemicals, fuel and the like when we make our rounds at the construction site.

We therefore place high demands on the contractor in terms of chemical and fuel storage, refuelling and consumption. We also always monitor the contractor's emergency preparedness, such as the presence of spill-absorbing materials, spill kits and safety equipment, and that the contractor follows the agreed spill procedures for fast, efficient and correct handling in the event of a spill.

On construction sites close to harbours, lakes or streams, we have extra focus on avoiding spills and leaks.

Wastewater is also called 'process water' and it is an important focus area. Many construction processes use water, for example when we cut concrete on secant piles, or in hydro-blasting, where water under high pressure makes concrete surfaces rough and ready for casting.

A large part of the process water also comes from seeping groundwater. The process water must then be channelled away from the construction site, but before that, it must pass through various types of water treatment plants. For example, this may involve a neutralisation process where the calcareous, alkaline water is mixed with acid to make the pH value more neutral.

Rainwater that falls inside the construction pit, for example in shafts and excavations, is actually also considered 'process water' and therefore it is also the responsibility of the builders to clean it before it is discharged into the sewer.

When working at depth, you inevitably encounter groundwater. We monitor the groundwater through computerised systems that can measure water values, water levels, pressure and more. There are very specific rules for how groundwater is handled - in most places the water is pumped back into the ground, in some places the water is diverted to another location.

When we pump up groundwater to return it to the ground outside the excavation pit, in some places it needs to be purified before it is returned. This way, in some contexts, we leave the area in a better environmental condition than when we arrived.

A good example is the former construction site at Strømmen in connection with the construction of M4 Sydhavn. The site used to contain a sludge basin, and the Gåsebæk trench, which was previously a rainwater channel that was first converted into an open and then a buried sewer, has run here. The groundwater in the area was contaminated by chlorine-containing solvents from the dry cleaners that used to be located further up the creek. With the construction of the metro shaft, we removed the sludge basin and filled it with clean materials, and all the groundwater we pumped up was purified before being returned to the underground.

We also have a strong focus on noise pollution. Here, rules apply that the average noise level must not exceed the urban noise limit. In addition, we also focus on air pollution.

An environmental consideration for these can be, for example, to avoid a lorry or machine idling and thus polluting (and making noise) unnecessarily, or that noisy work is shielded by the installation of noise barriers and covers.

You can read more about the permitted noise limits at our current construction sites here.

Our environmental inspections are reported using a smiley scheme similar to the Danish Veterinary and Food Administration. During the construction of M4 Sydhavn, we introduced an elite smiley competition, which in short meant that points were awarded based on performance during inspections. Each inspection started with green, happy smileys with a maximum value of 50 points. If the inspectors found remarks at the construction site, points were then deducted from the total score. If a site had five visits without any remarks, this resulted in an 'elite smiley' - and bonus points.

At the end of the year, the site with the most points could call itself 'Environmental Site of the Year', which resulted in a diploma and a delicious reward for the employees in the form of cake, sausages or similar.

The smiley scheme was a way to weigh up the different construction sites against each other and praise them for their environmental efforts. It creates a healthy competitive environment where each site becomes more aware and tries to take more environmental considerations into account.

At the same time, it breathed new life into inspections so that they were not perceived as a finger-pointing exercise, but as a centre of enthusiasm and desire for improvement.