SubsTer - Transforming quarry tailings into fertile ground

Project details

  • Main leader : Microhumus
  • Type of initiative :
  • Périmètre : France
  • Localisation : 18 rue d'Alsace, 54140 Jarville la Malgrange
  • Date de début : janvier 2016

Economy circular topics

  • Extending useful service life
  • Industrial and regional ecology
  • Recycling
  • Responsible consumption
  • Functional service economy
  • Eco-design
  • Sustainable procurement
Description

SubsTer® is a geotechnical engineering process that recreates fertile ground from tailings. SubsTer® can be used to:

  • recover unused materials
  • create substitute farmland for crops without stripping soil from existing fields.

SubsTer® produces substitute soil from quarry tailings and unsold production, leveraging unique expertise derived from a transfer of technology developed by INRA, CNRS and the University of Lorraine's Soil and Environment laboratory. SubsTer® uses transmission electron microscopy to characterise soils in order to recreate living earth. We regenerate soil by focussing our formulation activities on the micro-aggregation of mineral tailings with locally sourced organic matter that has microbial potential suited to the needs of each deposit. The SubsTer® process yields healthy living land that has not been obtained by depleting farmland and is not of variable quality as often the case with brownfield land. SubsTer® land is provided with an agronomic certificate attesting to its quality and harmlessness.

Qualitative benefits

Innovative approach

SubsTer is the first solution that produces renewable land while preserving the natural domain. 

SubsTer harnesses (1) advanced geotechnical engineering expertise acquired over many years of academic research and practical projects in arid desert environments and (2) expertise in soil organic matter microaggregates that we are able to apply under an exclusive worldwide licence from INRA and the University of Lorraine. 

Social benefits

From a social perspective, SubsTer can be used to create green spaces in urban areas, regardless of the local soil procurement sources. For example, in south west France, soil is scarce and relatively poor. 

Environmental benefits 

- Protect natural habitats by eliminating the need to extract topsoil from such environments, 

- Recover unused materials,

- Limit the spread of invasive species,

- Limit the spread of pollutants by avoiding the unregulated movement of potentially contaminated brownfield soil,

- Avoid unnecessarily filling (class III) inert waste storage facilities, 

- Reintroduce plants to urban spaces as part of the fight against global warming

- Limit carbon dioxide emissions by providing customers with local soil procurement sources (the most active quarries tend to be located near urban centres),

- Facilitate redevelopment of quarries and inert waste storage facilities for use as farmland,

- New avenue for recovering tailings that restricts landfill by burying only non-recyclable ultimate waste, thereby enhancing quarry acceptability. 

Carbon dioxide emissions reductions

- SubsTer can be used to preserve natural spaces and recreate landscaped areas: The contracts already signed represent a potential equivalent of 600 ha of safeguarded and newly created land.

Considering all soil types together, carbon emissions average 74 t per hectare in France.

Accordingly, the SubsTer contracts agreed during the launch year, will theoretically generate savings of 600 ha x 74 t= 44,400 t of organic carbon.

- SubsTer also delivers savings in terms of inert waste storage volumes equivalent to 1.2 million tonnes, based on the contracts signed over the first year of operation.

- By making local soil sources available nationwide, SubsTer helps to decrease the impact of soil transportation, particularly in areas where topsoil is in short supply. 

- Applying the SubsTer process to create urban green spaces enables carbon dioxide to be sequestered by plants (which also help to lower temperatures in urban areas). 

Economic benefits

SubsTer enables quarry operators to diversify their production activities and protect jobs at a time of economic uncertainty. 

SubsTer lets quarry operators recover materials previously considered unrecoverable (or even negatively-valued, due to landfill costs of approximately €3 per tonne, although this value fluctuates widely from €1 to €8, depending on location).

By creating an average added value of €5 per tonne, the SubsTer contracts already agreed will enable our customers to increase their margins by €7.5 million (corresponding to a potential 1.5 million tonnes of SubsTer soil, on the basis of the contracts signed in one year).

The Soil and Environment laboratory at the University of Lorraine (UMR 1120 - INRA) earns a royalty on each soil sample characterised using transmission electron microscopy;

Scope for replicating or relocating the initiative in other regions:

After inaugurating our demonstrator at a ceremony attended by the then-minister, Ségolène Royal, in June 2015, the SubsTer process has been commercialised throughout France since 2016 and has already been chosen by quarries in the Aquitaine, Languedoc-Roussillon, PACA, Rhône-Alpes, Auvergne, Bourgogne Franche Comte, Alsace and Lorraine regions. 

Now, in late 2016, we are opening an office to promote SubTer along France's Atlantic coast and plan to expand into Europe in 2018.

Stages of the initiative

Origins

Drawing on its expertise and experience garnered in the Middle East, Microhumus offered its services to a construction company, for a project to restore unpolluted brownfield land.

The aim of this proposal was to avoid excavating the non-functional top layer of soil, removing it for disposal and then purchasing earth for the new green spaces. This proposal, submitted in 2013 at the start of the sector-wide crisis, appealed to the customer but the planned projects were shelved. During the same period, our customer merged with another company from the same group and our contact, who had extensive experience in the construction industry, left his job. We decided at that point to work together to explore the potential for creating value by combining the cultures of our respective businesses.

Building on our experience in formulation engineering for fertilizer producers and in the creation of Biotechnosol engineered soils in acidic desert environments and brownfield industrial sites, we came up with the idea of applying this expertise to the quarry sector, not for restoring end-of-life sites but for recovering tailings, i.e. all the materials resulting from the production process that have no technical properties of interest to the construction industry.

Most quarry operators that produce aggregate (sand, fine and coarse gravel, etc.)° are unable to find commercial outlets for a variable portion (10 to 40%) of their production, which is of inadequate quality (due to the presence of clay or organic matter, or because the stone is too soft, for example). These materials, known as tailings, include materials scalped during the initial manufacturing stage, materials unsuitable for use in production processes that are exposed while stripping the top layer of the deposit, and unsold particle grades. Although such materials are not classified as waste from a regulatory perspective, they have no commercial outlets. 

Quarry operators are therefore obliged to manage widely fluctuating quantities of tailings stocks, which occupy large areas of land and in some cases over strategic land containing viable deposits. One possible solution for operators required to redevelop their facilities by bringing in inert materials or establishing inert waste storage facilities is to backfill these dedicated areas and empty pits. This self-filling reduces the facility's capacity, resulting in significant lost earnings and the need to open new inert waste storage centres to serve customers' requirements. This situation is not desirable from either an environmental or social point of view (and is an obstacle to acceptance by local residents). 

Over and above the technical ability to offer this service and the need for it among quarry operators, SubsTer enables end customers (local authorities, landscaping companies, construction contractors, private citizens, etc.) to avoid purchasing soil from untraced sources, in most cases farmland or natural spaces. The only alternative to such agricultural soil is to use brownfield soil, the agronomic quality of which can vary widely, even without considering the risk of spreading pollution or invasive species.

SubsTer is set to account for 30% of our overall business in 2016. In 2017, we intend to triple the number of customer sites in France (to 45) and have plans to roll out SubsTer to at least two sites in each of two other European countries. The share of total revenue represented by SubsTer is expected to remain stable, due to the growth in our other businesses and in particular our contaminated land and facility management services, for which 35 AgroPhyto projects and studies were carried out in 2016.

In 2018, our goal is to expand our European footprint, with an effective sales organisation in two of the following four zones: Benelux; Germany & Austria; Spain; Italy). Contacts have already been established in Spain and Austria. 

Implementation

Areas of activity

  • Construction
  • Recycling

Resources

  • Ores
  • Material efficiency
  • Building materials
  • Excavated materials

Pillar(s) of the circular economy

  • Extending useful service life
  • Industrial and regional ecology
  • Recycling

Technical resources

The SubsTer® process is used to formulate substitute soil that preserves farmland, provide users with soil of guaranteed quality and enable quarry operators to recover unsold products. During the formulation engineering process, Microhumus systematically ensures that raw materials from quarries and elsewhere (organic and microbial supplements) comply with applicable standards. Where no appropriate standards exist, analyses are performed to confirm the absence of pollutants. The SubsTer® soils formulated for producers must all comply with specified quality criteria, such as containing a minimum percentage of organic matter, an adequate fertilising capability or a certain level of biological activity, making these substitute soils ideal growing media for your plants.

Human resources

4 employees and 3 exclusive consulting agreements

4 research associates 

Cost & funding

Financers

    In recent years, Microhumus has invested in solutions based on technologies licensed from INRA and the University of Lorraine.

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Author of the page

Yan Thomas

Moderator

Cyrielle BORDE

Cheffe de service adjointe - Service Industrie