At the Ülemiste water treatment plant, prefilters are used to clean drinking water, which clean the water from suspension and colloidal particles. In 2023-2024, Traveter Grupp OÜ, in cooperation with subcontractors, carried out an extensive renovation of the A-building, Clarifier No. 4. This included demolition works, dismantling of process pipelines, concrete repair, renovation of barriers, reconstruction of power pipelines (AISI 304) and renovation of process pipelines. During the works, water leaks were closed, concrete floors, walls, posts and beams were repaired. The structures of the sedimentation tank were covered with a Sika MasterSeal PU-waterproofing system suitable for drinking water.

The materials were supplied by Primostar OÜ.