20. Oct 2017

Nordecon completed the design and construction work on the expansion of the Kohtla-Järve wastewater treatment plant

Nordecon completed the design and construction work on the leachate and contaminated rainwater cleaning system in the landfill which did not comply with environmental requirements for hazardous waste in the Kohtla-Järve oil shale industry. The work was started in December 2015 and the cleaning system was delivered to the contractor in due time in June this year. Nordecon completed the additional road design and construction work by the end of September. The total cost of the contract was 4.2 million euros with VAT.

“For Nordecon, the design and construction of the Kohtla-Järve wastewater treatment plant was very important. This is the largest environmental facility built in recent years, because there are very few water and sewerage projects in Estonia at the present time. It was also an exciting and challenging task, because the work had to be done in such a way that the existing cleaning system would work smoothly throughout the entire construction period. We thank our partner OÜ Aqua Consult Baltic and the production service of OÜ Järve Biopuhastus for the success in the unique and complex project,” said Erkki Suurorg, Member of the Management Board of Nordecon AS. “In Estonia, road construction and maintenance has dominated the construction industry for a long time. Construction of environmental projects is rather rare and more complicated engineering construction projects are irregular.”

According to Erkki Suuroru, Järve Biopuhastus and Nordecon have collaborated in the past. “For Nordecon, the construction work on the Kohtla-Järve wastewater treatment plant was the second collaboration with Järve Biopuhastus: in 2012–2013, several areas of public water supply and sewage systems were built and restored in Kiviõli city,” said Erkki Suurorg.

 In the framework of the Kohtla-Järve wastewater treatment plant contract, the following objects were designed and built:

  • a new entrance was established in the inlet chamber, additional pipes were installed to directly steer leakage to the 4th bioreactor, and from the emergency tank directly to the 4th bioreactor;
  • chambers for the 4th bioreactor feeder tubes were built in the distribution chamber, shield valves with an electric drive were installed to regulate the water levels between different bioreactors;
  • a sampler and different analysers were installed in the built analysers building;
  • 4th bioreactor (25 m × 175 m × 5.1 m) for cleaning leachate;
  • a chemical receiving unit was built in the chemical building and containers were reconstructed;
  • the automation control system SCADA was supplemented for the attached equipment and sensors
  • a new access route was built and the existing ones were renovated.


The work on the expansion of the Kohtla-Järve wastewater treatment plant was carried out as a public procurement and it was co-funded by the European Union Cohesion Fund. The project was supported by The Foundation Environmental Investments Centre (EIC) and The Ministry of the Environment?