How Gothenburg is environmentally constructing new metro tunnels

The West Link is an eight kilometre long double track railway, including a six kilometre railway tunnel, underneath the city of Gothenburg. Scheduled for completion in 2026, the £2.5 billion development - which also involves the creation of three new underground stations - will increase accessibility to the city, boost capacity and improve travel times.

The construction involves a large amount of tunnelling and concreting, generating considerable volumes of potentially polluting waters. To handle that, Siltbuster systems are being used to treat the waters generated during construction of the West Link project on the Gothenburg Metro in Sweden. This is the latest in a long line of high profile national and international rail projects to call on the Monmouthshire firm’s equipment and expertise.

The contractors, Nordic Construction Company (NCC), are excavating through granite, limestone, and clay for the tunnel and stations. During this work, the site’s surface water runoff and ground water can come into direct contact with the exposed soil, creating waters with a high concentration of suspended matter including fine, slow-settling, clay particles. If a significant amount of this material enters nearby drains and watercourses, it can block the gills of fish and smother aquatic plants and invertebrates, starving them of light and oxygen. The extensive concreting works during the construction phases will also create highly alkaline, cementitious construction waters with an elevated pH of 12-13 -- akin to oven cleaner -- again highly polluting to the environment if left untreated.

To deal with that, the required system needs to be not only capable of treating the high incoming flows to a verifiably high standard, but also offers a large treatment capacity for a small footprint. This is a key consideration, as the West Link is being developed within the centre of Gothenburg, next to the biggest amusement park in Scandinavia, The Swedish exhibition centre, the World Culture Museum, Gothenburg World Trade Centre, plus ice hockey and football stadia.

“With the construction work taking place in a high profile, densely populated, built-up area, and with a main highway linking Malmo to Oslo running nearby, space is at an absolute premium," explains Kristian Downs, Export Sales Manager, Siltbuster. "There’s limited room on site for additional plant and equipment. That’s why our iHB40R ticks all the boxes. It’s a highly effective, easy-to-use treatment solution, that’s agile and space efficient.”

“To be involved in yet another prestigious international project is a great endorsement for the expertise of our team, the robustness of our systems, the size of our fleet, our technical back-up and our growing reputation within the world’s construction sector,” he adds.

Siltbuster’s iHB40Rs units - part of a fleet of over 400 systems routinely hired out at short notice to construction companies around the world – were supplied for the Gothenburg project through its local distributor Clean Water Engineering, and will be on site for the next few years with estimated completion in 2026.

“The scale of this project is immense, and the requirements are very strict," says Johan Magnusson, CEO at Clean Water Engineering. "Siltbuster was the number one choice -- it has supplied four units to date, but there will be more on site soon. With space limited, it is great having a system that is not only compact and nimble, but more effective and efficient than any other system on the market.”

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