Ensuring optimum drinking water quality is a top priority. Therefore, the conditioning of water intended for direct consumption must be optimal. Which agents are best suited as drinking water conditioners? Not much has changed in this regard for many years, and phosphates – in different systems, concentrations, and levels – are certainly to be recommended.
Phosphates are useful as food additives (they are used, for example, in the manufacture of certain types of cheese and other dairy products, or confectionery). Due to the widespread use of these chemicals, detailed research on these inorganic substances has also been conducted for years. This allows us to be confident that they are safe, both toxicologically and physiologically.
The amount of phosphates in individual products must be within certain standards, and this is no different for drinking water. The legal limit is 5 mg/l P2O5. In order to condition drinking water effectively, significantly lower amounts of phosphate are needed, regardless of whether we are talking about water treatment procedures such as sediment reduction, corrosion protection, etc.
Widespread use of phosphates in drinking water conditioning
There are several key processes involved in ensuring the highest possible quality of drinking water that can be accomplished using various forms of phosphates.
- phosphates and corrosion
Phosphates are one of the best corrosion inhibitors – they inhibit corrosion processes at different levels and according to different needs. The effect of inhibitors depends on several factors: severity of corrosion, material of installation, physical and chemical conditions of water, flow rate of water and concentration of inhibitor.
In the fight against corrosion (i.e. in effect – the excessive supply of iron in water directed to the recipient) monophosphates and polyphosphates work best. Practice shows that the best results are achieved by creating preparations “dedicated” to specific installations. These are mixtures of monophosphates and polyphosphates in appropriate concentrations and quantities.
Phosphate inhibitors are characterized by high efficiency, low cost and complexity of action – hence their popularity for active corrosion control in drinking water systems.
- phosphates and calcium carbonate in water
Phosphates are excellent at stabilizing water hardness. What does this mean? The effective prevention of calcium carbonate precipitation in installations. High polymeric phosphates counteract this. Small concentrations of this type of phosphate are sufficient to effectively counteract scale formation in plumbing systems.
- phosphates and heavy metals in drinking water
Phosphates are very effective in reducing heavy metals, which can significantly reduce water quality. Due to their high harmfulness, the strictness of their permissible concentration becomes more demanding. According to EU standards they are respectively – for lead: 10 mg/l and for copper – 2 mg/l. Phosphates significantly reduce the release of copper as well as lead.
- phosphates vs. already existing sediments
It is also impossible not to mention this property of phosphates. They not only counteract the discharge and deposition of the above-mentioned compounds, but also effectively reduce already existing deposits. If the dosage is carried out correctly, the phosphates will deal with the deposits, reducing them gradually and at the same time effectively.