METHOD FOR REMOVING ARSENIC COMPOUNDS FROM DRINKING WATER Russian patent published in 2016 - IPC C02F1/58 C02F1/52 C02F1/72 C01G28/02 C02F101/10 

FIELD: treatment plants.

SUBSTANCE: invention can be used for cleaning water from water intake sources of arsenic compounds and heavy metals in production of drinking water, as well as for cleaning some industrial wastes of the above toxic agents. Method involves sequential processing of water with a precipitation agent based on compounds of iron (III), coagulation and filtration of water. Prior to filtration the heterogeneous system is settled, the deposit containing iron (III) hydroxide with deposited arsenic compounds (V) is dissolved in acid and treated with hydrogen sulphide with subsequent removal of arsenic in the form of a slightly soluble compound. Iron (III) salt solution is directed to a new cycle of water treatment. Settler is a mixture of hydroxy- and dihydroxy-iron (III) compounds with iron (III) hydroxide, which is obtained by exposing iron (III) salt solution to sodium hydroxide (potassium) or anion-exchange resin in OH^--form in order to achieve a 3.6 to 4.1 pH system.

EFFECT: method provides higher quality of water cleaning, achievement of arsenic cleaning parameters of not less than 10 mcg/l and heavy metal cleaning parameters of less than maximum allowable concentration, reduced environmental impact due to removal the precipitation agent containing a toxic agent from the cycle and its processing.

12 cl, 3 dwg, 7 tbl, 71 ex