Paving the way – from pollution to sustainable recycling of oil shale ash


Marjo Ronkainen

Project Manager
T: +358 40 551 1922

The purpose of this project is to show that it is possible to convert deposited and newly generated Oil Shale Ash (OSA) into valuable secondary materials for civil-engineering applications. This efficient and waste-free use of oil shale would reduce its impact on the environment while also generating economic benefits.

The Estonian challenge

Over 90% of the Estonian basic power supply is covered by oil shale – fired thermal power plants. Every year about eleven million tonnes of oil shale is fired. The most serious problem today is the handling of oil shale ashes (the ash content of oil shale is 45-47%), as more than six million tonnes of these ashes are produced annually. Currently this is mostly disposed of by spreading on land, which causes pollution of millions of cubic metres of rainwater each year.

Benefits world-wide

Main project objectives are:

- Showing and proving that OSA is an effective construction material.
- Providing know-how, information, and guidance on the environmental and economic benefits, and the technical potential of using OSA in civil-engineering applications in a wider scope, in Estonia as well as in the rest of Europe.

We hope that based on the results of our research there is solid input to renew for example road construction norm documentations and guidelines.

Ramboll has an important role as a consultant in this innovative EU LIFE+ project. We have helped to develop different binder recipes trough laboratory tests, we have made technical road design projects for the pilot sites, taking into account different OSA binders, we have compiled follow-up and survey plans, including making the monitoring of the project throughout the project. Besides, Ramboll is involved in progress reporting to the EU and dissemination of results.

Innovative and cost-saving

The innovative use of OSA as a binder gives it a good useful purpose, providing also a cost-effective yet high quality alternative technology in road construction. Conversion of industrial waste into valuable and environmentally friendly products is highly important at the moment in EU and world-wide. OSA can be used as a raw material in the construction industry, and could become an interesting and cost-effective replacement for cement and other expensive additives.

In Estonia, this could offset the need to import up to 500 million tonnes of natural aggregates from non-renewable sources, usually involving heavy long-distance transport across Europe.

In Ramboll Finland there is high level of competence and long term experiences in stabilisation methods development (layer-, mass-, and process stabilisation), which is used in numerous projects. Using this knowledge in Estonia with the important side product of oil shale ash, the OSAMAT project is a result of good knowledge sharing and cooperation between interested partners.

Large oil shale ash quantities

Eesti Energia as a producer of large oil shale ash quantities has found this project important to their innovative usages of OSA and promoting the material as more than just a side product of energy production. OSAMAT is a door opening project to OSA; from this project comes the knowledge of how to use it in road construction, but it gives a good base for next developments, for example  using it as a binder in contaminated sediment stabilisation if needed, etc.

The OSAMAT project is co-financed by the EU LIFE+ programme and the Estonian Road Administration. Project partners are the energy company Eesti Energia AS and construction company Nordecon AS. Ramboll is a sub-contractor to Eesti Energia.

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