METHOD FOR THE REGENERATION OF NITROGEN AND PHOSPHORUS FROM WASTEWATER BY PRECIPITATION OF THEIR IONS IN THE FORM OF STRUVITE Russian patent published in 2021 - IPC C02F1/58 C01B25/45 C01F5/00 C05B17/00 C05C3/00 C02F101/10 C02F101/16 

FIELD: wastewater treatment.

SUBSTANCE: invention can be used in wastewater treatment. The method for regeneration of nitrogen and phosphorus from wastewater by precipitation of their ions in the form of struvite includes precipitation of struvite at the initial molar ratio [Mg²⁺]:[NH₄⁺]:[РО₄^3-], close to the stoichiometric composition of struvite. In the presence of fluorine ions in the wastewater, water is pretreated by adding calcium carbonate, precipitation and separation of the calcium fluoride precipitate. The Mg²⁺ and РО₄^3- ions missing for the formation of struvite are introduced into the wastewater as an intermediate product, which is obtained by mixing solutions. In this case, a solution of magnesium chloride or sulfate is mixed in an amount that allows to obtain a molar ratio of Mg²⁺/NH₄⁺ from 1.1 to 1.2 in wastewater, and a solution of sodium or potassium phosphates, such as Na₃PO₄ or K₃PO₄ and Na₂HPO₄ or K₂HPO₄, in an amount and ratio that allows to set a pH in the wastewater in the range from 8.0 to 9.5 and a molar ratio of РО₄^3-/NH₄⁺ equal to 1.0. The resulting solutions are mixed at 25-70°С and intensive stirring for 1-2 minutes to prepare an intermediate product, which is introduced into the wastewater immediately after cooking when it is mixed. The resulting suspension is mixed for 15-20 minutes, the precipitate is settled for 20-30 minutes, the clarified water is separated by decantation.

EFFECT: invention makes it possible to increase the degree of extraction of NH₄⁺ и РО₄^3- ions from wastewater while simultaneously precipitating ammonium and phosphate ions in the form of struvite, preventing the appearance of impurities of other phases in the composition of the precipitated product.

1 cl, 1 dwg, 9 tbl, 5 ex