The process of threshold treatment involving the addition of WTP H307S in drinking water was originally used for stabilisation of calcium carbonate in hard waters, thus preventing scale formation with increased temperature. A similar addition of WTP H307S is now widely used for corrosion control in soft waters.
Corrosion results in many problems, one of the most important being the discolouration of water, known as red water. Discolouration of a similar kind can also be caused by precipitation from solution of naturally occurring soluble iron compounds. Threshold treatment with WTP H307S can be used to control the discolouration arising from either cause.
Protection depends on the formation of a very thin film, usually containing iron and calcium although other bi-valent metals may replace the latter. This film is cathodic in character i.e. it suppresses the release of electrons at cathodic areas on the metal and is impermanent, it needs to be kept in a state of good repair therefore by the constant supply of fresh inhibitor.
As many applications are in municipal supplies the effect of phosphate on the potability of the water is of great importance. DWI approves the use of polyphosphates and silicates. All the components of WTP H307S are food or potable grade.
The above information is believed to be correct but does not purport to be all inclusive and shall be used only as a guide. The company shall not be held liable for any damage resulting from handling, contact, mis-use or mis-application of the above product. In all instances the user should satisfy themselves that this product is suitable for the anticipated application and should carry out suitable and sufficient risk/COSHH assessments and a method of use statement.