Abstract: A step iron for a concrete structure, the step iron comprising a body and a leg; the body and leg each comprising a metal core and at least partially encapsulated in a polymer material; the body comprising a tread length to enable a user to use the step iron for climbing; the leg comprising a proximal end nearer the body and a distal end; the distal end of the leg comprising an end section to abut a complementary section of an insert which is fixable and embeddable within a concrete structure; a fixing means mounted on the leg to enable reversible engagement with a complementary section of the insert.

Abstract: A water treatment system comprising: a container having a first end, a second end and a container wall defining an interior and an exterior; an aerator completely disposed within the interior, the aerator comprising an aerator wall having a plurality of perforations, the aerator configured to rotate in a liquid contained in the interior such that the aerator is partially disposed in the liquid, the aerator configured to aerate the liquid, wherein the plurality of perforations are configured to lift a thin film of the liquid from the container by exploiting the surface tension of the liquid, wherein the thin film bridges the plurality of perforations, and the aerator is configured to create a cascading bubbling turbulent flow in the liquid flowing along the aerator wall, as well as the liquid contained in the container; and a rotary motive force element coupled to and configured to rotate the aerator.