There are several methods of water purification from nitrates, which differ in its essence, technical facilities, cost and purity. In accordance with the specific requirements and characteristics of the object professionals opt for one of them.
The most popular method of water purification from nitrates is to use ion-exchange systems. It is based on sequential filtering water through a hydrogen-cationite and then HCO3-, OH- and CO3 2 - anion-exchanging filter. Equally important is the treatment of water from sulfates.
This method of water purification from nitrate is widely used in the industrial and energy sectors, as demonstrates the high quality of water purification. Depending on the purpose of water purification processes, hydrogen-cation exchange and hydroxide anionirovaniya have varying degrees of complexity.
In the first stage of water treatment in hydrogen-nitrate filters cationite cations contained in the raw water are exchanged for hydrogen cations. In the filtered liquid formed from an equivalent amount of acid anions, which were bound cations and CO2 formed during the decomposition of hydrocarbons removed in the calciner.
The second stage of water purification involves the use of nitrate anion-exchanging filters (and also used in water purification from heavy metals, where the acids formed anion is exchanged for OH- ions, that is retained by the filter. This nitrates from water treatment is completed.
Depending on the desired depth of water purification from nitrates experts use one-, two- and three-stage installation. Common to them all is the use of strongly hydrogen-cation. So, for water purification from nitrates and phenols from water treatment to industrial and power plants water treatment can be carried out:
The salt content of the water after purification by single stage scheme of nitrate 2-10 mg / l by a two-stage ;, - 0.1-0.3 mg / l; by a three-stage - 0.05-0.1 mg / l. Therefore, household water purification from nitrates used single-stage scheme.
It has this water purification scheme of nitrates and its drawbacks. They are derived from the following features of the process circuit. The vast majority of structures of ion-exchange filters for water purification from nitrates - the exact parallel (straight-through), that is, treated water and recovery solution in the filter moving in one direction - from top to bottom (as in water purification from iron).
In the process of moving through the resin bed downward pressure concentration is significantly reduced. At the final stage of regeneration solution collides with the layer of ion exchanger, containing a small amount of ions to be driven out of this layer, however, displacement occurs. This leads to the next stream to be processed in the water removal of nitrate has a low quality.
Therefore, single-stage ion-exchange water purification from nitrates is associated with the use of large quantities of reagents, as well as a large amount of water for washing the resin residues from regeneration solution, and water treatment quality leaves much to be desired. The two-stage and three-stage scheme to overcome these disadvantages.
One of the most productive and effective ways to purify water from nitrates - a reverse osmosis method. Advantages of the method consists in the simplicity of implementation of activities and installations of structures, as well as ease of operation of the system, low energy consumption, small size. This method is used when the same iron removal.
reverse osmosis method is used to purify water from nitrate salt content at up to 40 g / l. Its essence is to use a special semipermeable membranes partitions. In the course of water purification method of this nitrate solution was separated and the solvent, since the first membrane passes through itself, and the second - no. The solvent flows through the membrane as long as the concentrations of the solutions on either side of the barrier will not be identical.
Osmosis (Greek .: osmos - push pressure), - a water purification process of nitrates in which substances spontaneously move through the semipermeable membrane, resulting in a solution of two different concentrations.
Osmotic pressure - this is quantitative characteristic of the reverse osmosis phenomenon, which creates a fluid transition to change speed through the membrane. Such counterpressure generated in the course of water purification from nitrates, equal to the pressure that must be applied to the solution to bring it into equilibrium with the pure solvent, separated from it by a semipermeable membrane.
reverse osmosis method used for water purification from nitrates, was invented in the US in 1953 and was based on the properties of cellulose acetate semipermeable membrane. partition structure has been continuously improved, and now there are lots of them: the component suitable for storing in a dry form, and so on.
When cleaning water from nitrate experts in any way rely on the normal contents of these substances in water, which in turn depend on the purpose for which the water used. Thus, the nitrate content in drinking water should not exceed 0.50 mg / l.
The most common reason that there is a need for water purification from nitrate - is the use of nitrate fertilizers: their surplus falls into the ground water, and then - in reservoirs, from which extracts the water people, so you need as water softening.