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Merko’s Elva waste water facility ensures modern waste water treatment for more than 6,000 residents


A new environmentally friendly waste water treatment centre will make it possible for more than 6,000 residents of the city of Elva and small town of Käärdi to join a modern waste water treatment centre. The new centre will treat waste water from the entire area and handle waste water sediments, which will result in a greatly reduced environmental risk as well as decreased risk of the waste water from the area entering the natural environment. The construction on the treatment centre was performed by AS Merko Infra and AS Merko Ehitus Eesti.

The impetus for the entire major undertaking was the fact that only one-third of the city of Elva was connected to the public water works and sewerage system, noted Andres Aruhein, a member of the management board of the contracting entity for the project, AS Emajõe Veevärk.

“The goal was to cover all of the territory of Elva and at the same time rebuild and extend both the drinking water treatment centre and the waste water treatment facility. We are currently at the point that most of the pipeline has been constructed. The waste water treatment plant is now ready and the drinking water treatment plant will be finished by the end of this year,” said Aruhein.

“In the course of the work, we built a new waste water treatment centre with four reinforced concrete tanks and also performed other necessary work – we built a separate reservoir-pumping station, established two pumping stations in the ground, dredged the existing aeration and settling ponds which have a total area of 8,900 m²and for the purposes of solidification of sludge, we built an asphalt-paved settling and solidification field with an area of 2,500 m² and erected fencing around the territory. A total of 1,800 metres of stainless steel and plastic pipes were installed in the treatment facility. We completely demolished the old treatment plant after the new one went into operation and reconditioned the land area,” said the project manager for AS Merko Ehitus Eesti, Viljar Paas.

The new waste water treatment facility has a capacity of 1600 m³/d and 90 m³/h and has a pollution load of 11,000 ie; it operates on the basis of the activated sludge process in a sequencing batch reactor, it is fully automated and can be remote-tracked and remote-controlled using computer and communication equipment. In addition, an automated HUBER microscreen – along with a grit trap and skimmer – was installed for mechanical treatment, the capacity of the filter is 234 m³/h (65 l/s). Technical equipment installed include 4 AERZEN blowers, 2 decanter overflow devices, 2 Seepex screw pumps, 2 drainage pumps, 2 chemical pumps, 6 mixers and 600 aerator elements in the process tanks. For the purpose of sludge treatment, a sludge centrifuge and polymer manufacture equipment were installed. A ventilation system, electrical and automated equipment was installed in the treatment plant building.