Nitrate removal from drinking water
Nitrate level in drinking water
Nitrate is quite harmful because it is transformed to nitrite in the human organism. The emerging nitrosamines are carcinogenic. Especially the health of babies is at risk. In addition to that other diseases (diabetes, Alzheimer’s and Parkinson’s disease) may be encouraged.
Often nitrate stems from excessive use of fertilizers in agriculture. Frequently nitrate charge indicates the presence of water contaminating microorganisms.
To lower the nitrite level below the limit value an ion exchange technique (similar to the one used for water softening) is applied.
Ion exchange technique
At the surface of the ion exchange resin the nitrate is exchanged for chloride. This water is than blended with the raw water to reach a certain limit. As the ion exchange resin is not highly selective to nitrate also sulfate is removed. To regenerate the ion exchange resin the same salt (sodium chloride) as for water softening is used.
Mixed bed systems: Nitrate removal and softening
Due to the similarity to the water softening process – which also uses an ion exchange resin and sodium chloride for regeneration – it is possible to combine the processes in one system. They contain a mixture of two different ion exchange resins: one for nitrate removal and another for the removal of calcium and magnesium. If both treatments are desired, a mixed bed system may reduce space requirement, investment and operating costs.
Dimensioning the system
To correctly dimension a system for nitrate removal several parameters of the water have to be taken into account: time averaged flow rate, peak flow rate, nitrate and sulfate concentration as well as water hardness in case of a combined filter system for simultaneous softening.
We design and dimension the system for you. Feel free to ask our experts.