The presence of nitrates in the water are usually from the use of fertilizers. Dec.-Law no. 306/2007 establishes as a parametric value 50 mg / l.
Nitrate can be removed to water by ion exchange or reverse osmosis (RO) systems. This housing (RO) system, applied to a tap for consumption, establishes a high removal efficiency at a low cost. For large or multiple uses, domestic or industrial, ion exchange regeneration systems are preferable.
Specific ion exchange resins for removal of nitrates from water. These resins exchange the nitrate ions with chloride ions. Regeneration is carried out with a saturated solution of salt. The equipment used to perform this type of treatment is a removal filter system, consisting of an automatic filter whose filter medium is a strong anionic resin exchange and where the control of steps, service and regeneration , is performed automatically by a volumetric programmer.
NITRATES REMOVAL FILTERS
How does it works?
Removal of nitrates by ion exchange is similar to the water “softening” process, with a small difference in resin polymer. The resin removes nitrate (and sulfate, due to its chemical similarity) from water and replaces chloride ions. When the resin bed reaches exhaustion, the control valve performs regeneration of the bed.
This is done by passing salt water (made with common salt dissolved in water) through the bed of resins, which processes the replacement of the nitrate and sulphate ions by the chloride ion, which are then eliminated in the outflow. After a final wash to remove excess salt, the unit is automatically ready to go into service. The only requirement is to ensure the user that the brine tank is kept filled with salt.
|Liters of resin (Lts)||15||30||50||80||125||225||350||500||750|
Flow rate (m3/h)
|Salt tank (lts)||100||100||150||200||300||500||1000||1000||1500|