METHOD, APPARATUS AND ION-EXCHANGE UNIT FOR TREATING WATER

The group of inventions relates to technology for producing solutions of mineral fertilizers. In order to process source water, three consecutively arranged ion-exchange columns are used: two having a cation exchanger in the form of a substantially cation component of a fertilizer to be produced; and one having an anion exchanger in the form of an anion component. A solution is sent from the outlet of the cation column that is second in the direction of flow to a nano-filtration unit, resulting in the production of a concentrate and a permeate. A part of the permeate is sent to the column containing an anion exchanger, resulting in a solution of a complex mineral fertilizer at the outlet of said column, and the other part is sent to a desalinator to produce, at the same time as the fertilizer, desalinated water for preparing a fertigation solution. After desalination, the salt concentrate is used to regenerate the cation exchanger in the aforesaid cation column. The regeneration product of this column is used, together with a salt containing the cation component of the fertilizer to be produced, to regenerate the cation exchanger of the column that is first in the direction of flow. In the column having an anion exchanger, the ion exchanger is regenerated using a salt containing the anion component of the fertilizer to be produced. Three columns like those described above are additionally used, forming pairs with the latter. In the second columns of said pairs, the ion exchangers are regenerated at the same time as the water to be processed is passed through the first columns, and vice versa. The inventions make it possible to reduce the amount of simple fertilizers used and the volume of waste solutions. Ce grupe d'inventions se rapporte aux techniques de production de solutions d'engrais minéraux. Afin de traiter une eau de départ, on utilise trois colonnes d'échange d'ions disposées séquentiellement, deux avec un cationite sous forme de composé essentiellement cationique de l'engrais obtenu, et une sous forme de composé anionique. La solution à la sortie de la seconde colonne cationique dans le sens de l'écoulement est dirigée vers une unité de nanofiltration afin de produire un concentré et un perméat. Une partie du perméat est envoyée vers la colonne avec l'anionite afin de produire à sa sortie une solution d'engrais minéral complexe, et l'autre partie est envoyée vers un purificateur afin de produire, en même temps que l'engrais, une eau dessalée pou