Sulphide Soil Assessment Tool – User Lab

In connection with housing construction and infrastructure projects, hundreds of thousands of tons of sulfide soil are excavated annually in Sweden. Sulphide soil occurs along the coastal area from Mälardalen in the south to Haparanda in the north, and correspondingly, sulphide soil occurs along the Finnish coast of the Gulf of Bothnia.

Sulfide soils are difficult from a geotechnical perspective with high water content, and high clay and silt content, which means that they are difficult to use as a construction material. Incorrectly handled, the soil can also acidify ground and groundwater and in some cases also acidify waterways and lakes with elevated levels of aluminium, among other things.

There is currently no classification of sulphide soils in practice, which means that all sulphide soils are assessed as potentially acidifying. This often leads to landfill and long transports. In the worst case, the presence of sulphide soil is missed completely, with acidification as a consequence.

In the research project Management of Sulfide Soils (MoSS), funded by the Swedish Transport Administration, SBUF and the project partners, a differentiated classification and assessment system was developed. The result showed that up to 30% of the volume of sulphide soil is not acidifying and the need to deposit can be less than about 50%.

The assessment system is based on analysis of the soil's sulphur, iron and calcium content as well as measurement of the soil's pH. With this differentiated classification, sulfide soil can be sorted based on acidification potential and set aside for different purposes or deposited more cost-effectively and environmentally than at present. The classification, which also means a simpler and faster assessment, provides opportunities to begin investigations into future excavation work at an early stage.

In order to be utilized effectively, it was judged that the assessment system should become more user-friendly and accessible, this would also contribute to a more industrialized process of dealing with sulphide soils that are not as dependent on specialized expert knowledge.

Work to increase the user-friendliness and make the assessment system available through a digital tool was started thanks to funds from the Innovation Idea call in the spring of 2022 and 2023, where business and price models as well as a business plan were investigated.

The purpose of the proposed project is to continue the work done in previous projects funded by Innovationsiden and in a user lab test the offer (assessment tool with supporting training) developed in previous projects.

This should contribute to a user-centered development as well as a developed knowledge of the user's alternatives to using the tool, which in turn should give input to the pricing of the offer. The work also includes identifying effective ways, which meet user preferences, to offer supportive education.

At the end of the project, the goal is to have developed, with the user as a starting point, the tool and training offer that supports the management of sulphide soils and thus contributes to an industry-wide approach to sulphide soils. This also includes having established pricing and developed a payment solution.

The project's sub-goals are 1) Conducted user lab 2) Developed tool, 3) Determined pricing and 4) Developed training concept. The collaboration with need owners (technical consultants, contractors and builders) takes place in connection with the user lab and in the implementation of the developed training concept.