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Water treatment

For many years, our researchers have been developing various products for use in water treatment. On account of their special properties, phosphates and purified phosphoric acid help to reduce the risk of pipework corroding, prevent the deposit of limescale, control the pH of water, and control red and black liquors. Fluorine derivatives such as NaF and SSF are used in the fluoridation of water.

water treatmentindustrial waterdrinking waterwastewater
drinking water

Corrosion inhibition

Phosphates are used to reduce corrosion in water mains. This may be either :

  • anodic corrosion: Certain ions present in the water (calcium, lead, etc.) combine with orthophosphates to form precipitates that do not dissolve easily. These precipitates deposit on the walls in the form of a protective film.
  • cathodic corrosion: In addition, oxygen present in the water oxidizes the metal on the inner wall, releasing metallic cations into the water. The polyphosphates combine with these released ions to form positively charged bonds, which result in a protective film being deposited on the inner wall. This slows down the corrosion process.

Control of red and black liquors

When water is exposed to the oxidizing action of air and chlorine, color changes can occur in the water. If there is precipitation of iron compounds, water from the system may turn a reddish color (red liquor). Similarly, if manganese precipitates, a blackish color may be observed (black liquor). Some phosphates can trap these metals, even in very weak concentrations, and can control these liquors.

Fluoridation of water

Fluoridation of drinking water has been commonplace for decades in many countries including the United States, Australia and the United Kingdom. It is designed to improve the dental health of the population by reducing the risk of tooth decay.

Limescale inhibition — softening agents

Hard water causes the formation of limescale deposits which result in higher operational costs. When limescale builds up it can cause a lower flow rate through the pipes, which in turn inevitably means increased pumping and cleaning costs. Polyphosphates can trap calcium and magnesium. Calcium is the source of limescale formation and can dissolve the compounds formed, which prevents deposits from building up. Depending on the pH of the water, preference will be given to either SHMP (sodium hexametaphosphate) or STPP (sodium tripolyphosphate).

pH control

Another vital parameter in water treatment is controlling the pH of the water. The pH is the concentration of H+ ions in a water solution, and ranges from 0 (acid) to 14 (alkaline). A pH of 7 is neutral. Due to their buffer (pH regulating) capacity, orthophosphates and purified phosphoric acid can keep the pH level of the water as constant as possible.

Lead precipitation agent

Some older buildings still have their original lead piping. The presence of lead (Pb) in the water can be harmful to human health. In order to avoid dangerously high lead content in water from the system, a small amount of purified phosphoric acid can be added to encourage a "'coating"' to form on the inner surface of the lead pipes, thereby preventing the lead from being released into the water.

Lead (Pb) precipitation agent

Older buildings are still sometimes fitted out with lead piping. The presence of lead (Pb) in the water can be harmful to human health. In order to avoid dangerously high lead content in water from the system, a small amount of purified phosphoric acid can be added to encourage a 'coating' to form on the inner surface of the lead pipes thereby preventing the lead from being released into the water.

pH control

Another vital parameter in water treatment is controlling the pH of the water. Due to their buffer (pH regulating) capacity, orthophosphates and purified phosphoric acid can keep the pH level of the water as constant as possible.

Corrosion inhibition

Phosphates are used to reduce corrosion in water mains. This may be either anodic corrosion or cathodic corrosion.

Limescale inhibition — softening agents

Hard water causes the build-up of limescale deposits in pipes, leading to a lower water flow rate and therefore higher pumping and cleaning costs.
Polyphosphates can trap calcium and magnesium. Calcium is the source of limescale formation and can dissolve the compounds formed, which prevents deposits from building up. Depending on the pH of the water, preference will be given to either SHMP (sodium hexametaphosphate) or STPP (sodium tripolyphosphate).


Source of nutrients

The petrochemicals and agrifood industries, and in general, industries which discharge water with a high BOD (biological oxygen demand), purify the water biologically to reduce the BOD. To be effective and to develop, the bacteria used in these procedures require the nutrient P (phosphorus), but they also need optimum pH conditions. If any of these elements is missing, then the following products can be used as a source of phosphorus (either alone or in combination): purified phosphoric acid, monoammonium phosphate (MAP), diammonium phosphate (DAP), and monopotassium phosphate (MKP).

For more information on our full range of macro and micro nutrients for the biological treatment of wastewater treatment plant, visit www.solustep.com.

Solustep

Sequestration and precipitation of metal ions

Phosphates, and in particular SHMP (sodium hexametaphosphates) and STPP (sodium tripolyphosphate), can trap and precipitate ions in soluble compounds thus preventing deposits from forming (cf. Corrosion inhibition - Limescale inhibition/softening agents - Control of red and black liquors).

pH control

Another vital parameter in water treatment is controlling the pH of the water. The pH is the concentration of H+ ions in a water solution, and ranges from 0 (acid) to 14 (alkaline). A pH of 7 is neutral. Due to their buffer (pH regulating) capacity, orthophosphates and purified phosphoric acid can keep the pH level of the water as constant as possible.

 

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