Just under a fifth of the concrete that the Fehmarn Tunnel will be built from consists of water. And when you have to use a total of three million cubic meters of concrete for the tunnel elements alone, that’s over a million cubic meters of water – or over a billion litres. Femern A/S has already received a commitment and permission to use tap water. In other words, the same water comes from the tap at home in the kitchen.
Purified waste or drainage water
However, Lolland Forsyning would very much like Femern A/S to consider using so-called “grey water” for concrete production instead. Clean drinking water is a scarce resource. Gray water is purified rainwater from the sewer or purified water from the pumping stations that drain the water from the dammed area in South Lolland.
Underground water enough – right now
There is enough clean groundwater to supply Lolland with drinking water and, simultaneously, ensure the companies’ supply of process water – including the element factory in Rødbyhavn. However, Lolland Municipality is working to be able to supply the companies with grey process water in the future.
Due diligence
– It is not appropriate to use tap water. After all, it is not an infinite resource, and that is why we try to step on the brakes a little. Our studies show that it appears to be technically possible for us to supply the companies with grey water, and it also appears to be financially sustainable. There is enough water for both citizens and businesses, so it is more a question of timely care, says municipal manager Thomas Knudsen from Lolland Municipality.
Water is not just water
There is still very limited experience with using grey water for concrete production, and the water quality directly influences the concrete’s quality. The water’s content of, for example, chemicals and minerals can significantly impact the concrete’s durability, density and load-bearing capacity. Therefore, several studies are still pending before the green light can finally be given for a more sustainable solution with grey water.
Hoping for a technical solution
However, Lolland Municipality hopes that a technical solution can be found for this so that the element factory can use grey water in the long term. If the element factory can be preserved on Lolland after the Fehmarn connection is completed, an extraordinary amount of water will be needed for future projects.
