Waste water tanks are one of the most demanding structures in industry and municipal engineering. Their conditions put concrete and coatings under a variety of stresses – simultaneously and continuously. The combined effect of these factors places a very heavy life-cycle load on the structure, requiring both the right working methods and the right coating system.
Wastewater is not just water, it contains:
In particular, microbial corrosion (MIC) caused by hydrogen sulphide (H₂S) is a rapid and severe mechanism of destruction of concrete and metal reinforcement. In pools, H₂S is converted by bacteria into sulphuric acid – which corrodes concrete faster than most industrial chemicals.
The heat, humidity and organic material in waste water basins create the perfect conditions for microbial growth.
Concrete is exposed:
These accelerate chemical deterioration and weaken the adhesion of coatings unless the surface is professionally cleaned and roughened.
Pool coatings and concrete structures have to withstand:
Over time, wear will deteriorate both the concrete surface and the previous coating – especially if the substrate has not been properly roughened before coating.
In the Finnish climate, outdoor waste water basins are vulnerable:
Moisture is absorbed into the concrete and expands as it freezes, causing:
When concrete loses its compactness:
This leads to rapid deterioration of the structure and even environmental risks if leaks occur.
Kotek’s strength is that the entire process is done in-house – from substrate cleaning to the final coating.
This is critical, as the coating of wastewater ponds will always fail if any step is skipped or done using the wrong methods.
The substrate is cleaned with high pressure (2500-3000 bar) or water pickling (2000-2500 bar, with material removal), whereby:
This is the only proper way to clean wastewater basins – sandblasting is not enough for deeply absorbed residues.
Weak parts of the concrete surface are levelled:
The aim is to achieve a dense and uniform surface with maximum adhesion of the coating.
Kotek uses suitable coating systems.
The most common coatings for waste water tanks:
The coating is selected based on the chemical stresses, temperature and mechanical wear of the pool.
When all the steps are done correctly:
Kotek Factory Service Oy’s one-stop service ensures that all stages are handled by a single operator – without any middlemen and without the risk of missing steps.