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Merko: Iru waste-to-energy unit’s boiler plant facility is supported by a close to 1,000-tonne steel structure made up of over 10,000 parts


The general construction and specialized work on Eesti Energia’s Iru WTE unit, which opened today, was performed by Merko Ehitus Estonia on the basis of a contract with the international waste incineration plant expert, the French firm CNIM. The Iru waste-to-energy unit’s boiler plant facility’s nearly 1,000-tonne three-dimensional steel structure made up of over 10,000 parts was engineered in cooperation between companies from three countries and assembled to a millimetre’s precision in a space occupied by large-scale machinery.

“Iru waste-to-energy plant is a complicated and extraordinary project from the construction aspect already for the fact alone that it is only the second waste-to-energy plant in the three Baltic states. As the heart of the plant is its waste incineration and energy production buildings, the design and construction of the buildings stemmed mainly from the technological needs, measurements, loads and the schedule for installation. The building’s bulk is densely filled with various industrial machinery that made the 3D design – carried out in collaboration with CNIM – critical,” said Merko Ehitus Estonia project manager Priit Pullerits.

The entirety of the technology needed for WTE operations was designed, supplied and installed by the prime contractor, the French company Constructions industrielles de la Méditerranée (CNIM), which is a valued expert in the field of waste incineration and one of the largest builders of waste incineration plants worldwide. Merko performed the general construction and specialised work along with all of the necessary design work.

“One of the most complicated challenges was the design and assembly of the steel frame of the boiler plant, which had to fit between and around massive pieces of machinery with literally only a millimetre to spare in many places. Making the engineering even more difficult was the fact that the design of the equipment was managed from CNIM’s office in Paris and we commissioned the design of the structures from an experienced Finnish company. Thanks to modern information technology , it proved possible to assemble the 45-metre high, over 1,000 tonne three-dimensional steel structure, with its over 10,000 separate parts, without serious problems and with no need for any re-dos,” said Pullerits.

Pullerits said the design of the ventilation systems required special attention, as an unusually high amount of heat is emitted into the building, occasioning the need for large amount of air exchange. Ventilation of the Merko-designed waste hopper and the Merko-installed active air filters are extremely important for normal functioning of the building, ensuring that the air released into the atmosphere is at the required level of cleanliness.

The two and half years of collaboration between CNIM and Merko Ehitus Estonia passed in an atmosphere of trust, and Merko met all deadlines without fail, including obtaining the building permit and authorization for use, and remaining on schedule for the transfer of control of the site to the Eesti Energia by the deadline.

„CNIM is very international company and we have a lot of experience co-operating with construction companies all over the world, but it is the first time in all our projects to do co-operation with a company learning so fast. Construction process has really important and critical part in the project especially in terms of time schedule. Merko knows the local conditions, they have good engineers and design office and strong knowhow so we would like to repeat the success story in our other projects if Merko would be more active also outside the Baltic states,” said Jean-François Brua, Sales Director Northern Europe of CNIM.

“We’ve had excellent cooperation with Merko and the site team has been forthcoming in many areas to keep our mutual relationship running smoothly. The construction process has proceeded rapidly and professionally, and in particular I’d like to mention the high quality of Merko’s concrete work,” said Eesti Energia Iru power plant development director Urmo Heinam.

The work performed by Merko Ehitus Estonia included the general construction and building systems for the Iru WTE plant, including the ventilation and electrical work. In total, it took 7,000 cubic metres of reinforced concrete and over 3,000 tonnes of construction steel to complete the plant. Besides jobs Merko is accustomed to doing, a number of specific systems auxiliary to equipment and technology were built, such as pressurized air system and an industrial wastewater cleaning system. Merko’s contract also included design of the high- and medium-voltage parts and installation work. Among other things, Merko also built a truck scale and access system, all fire alarm systems and an access road from the brand-new road interchange on Saha-Loo road. Under the contract between Merko and CNIM signed in 2010, the cost of the work was 16.1 million euros, plus VAT.