How the Mass Consolidation Centre works

Each year, 19 million tonnes of excavated rock and soil materials are used for constructing buildings and infrastructure in Stockholm County. At the same time, construction projects generate 16 million tonnes of material annually, of which only a small portion is reused. The majority is often transported over long distances, which is unsustainable both environmentally and economically.

To address this inefficiency and promote the reuse of local materials, the Mass Consolidation Centre was established in 2018 at Frihamnen, Stockholm Royal Seaport. The facility, funded by the City of Stockholm's climate investment funds, aims to locally sort and remediate materials such as soil, clay, and crushed stone, reducing both the environmental impact on surrounding aquatic environments and the need for transportation. The material is then used, among other things, for backfilling when new streets and blocks are constructed in Stockholm Royal Seaport.

Since the facility began operations, the centre has undergone a development process and several development projects and collaborations have been initiated. In autumn 2023, capacity was significantly increased when the dry screening facility was supplemented with a wet screening plant. This enhancement raised the potential for reusing excavated materials from 35 per cent to 80 per cent.

The wet screening plant improves the ability to sort soft excavated materials. The new wet screen can sort particles down to 1 mm for reuse. This also helps to reduce the volume of material that must be sent to landfill. All sorting takes place inside a hall building, which reduces both dust and noise. A stone crushing plant enables the onsite reuse of clean rock materials.

The wet screening plant increases the ability to reuse materials.

During 2023, the volumes handled at the Mass Consolidation Centre increased to 530,000 tonnes of rock and excavated materials, most of which arrived by barge from the expansion of the underground network. The city has collaborated with the Stockholm Region and the Extended Metro Administration for several years to receive and reuse rock materials. The Mass Consolidation Centre also handles excavated materials from other urban development projects in Stockholm such as the Slakthusområdet (Stockholm’s meatpacking district) and Slussen. The local circular handling of materials resulted in a reduction of approximately 2,500 tonnes of CO_2e in carbon footprint and a cost saving of about 650,000 SEK in 2023.

To date, the Mass Consolidation Centre has managed 1,050,000 tonnes of rock and excavated materials, of which 540,000 tonnes came from various contracts in Stockholm Royal Seaport.

Strategy for Mass Management in Stockholm County

To establish a circular and climate-adapted management of excavated rock and soil materials in Stockholm County, a new strategy was developed and launched in autumn 2023. It is the first mass management strategy in Sweden with broad regional support. Stockholm city has adopted an action plan for mass management in 2024, which specifies how the city will work to achieve the goals of the county's mass management strategy. The action plan for mass management provides support in the process as it clarifies and creates better conditions for more circular and resource-efficient management of materials in the city.

It also outlines a common path and contributes to achieving the goals of the city's environmental program concerning mass management. The approaches in the action plan are intended to permeate all urban development and can thereby help to reduce the amount of unnecessary surplus materials through the reuse of soil and rock.

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The transports are carried out by barge to the Mass Consolidation Centre," explains Fredrik Bergman, Implementation Manager for Stockholm Royal Seaport, Stockholm City Development Administration. (Swedish only)