For certain types of water treatment, a small prefabricated compact clarifier will suffice. The manufacture of these models has evolved over the years. The first clarifiers were made of carbon steel, stainless steel, FRP (fiberglass-reinforced polyester) and had an exterior structure made of carbon steel, before we reached more modern models made of polypropylene with a carbon steel reinforcement structure.
The change in manufacturing materials for this type of clarifiers simply followed the natural course of evolution towards a highly resistant material, able to stand corrosion while still offering financial advantages. The last step was to cover the mechanical reinforcement (namely the external cross-linked structure that gives rigidity to the clarifier) with polypropylene plates. This extremely simple step was, however, of utmost importance, as it covered the clarifier exterior facade with polypropylene sheets. This way, the only remaining area that could still suffer from corrosion was finally protected.
This finish, as seen on the photographs, also improves the physical aspect of the installation and makes it look as though there is no external cross-linked structure.