Efficiency of Wastewater Treatment from Pollutants: Urea, its Derivatives and Sodium Chloride

A quantitative assessment of the efficiency of wastewater treatment is given. It is shown that treatment plants effectively remove nitrogen-containing components from wastewater through a chain of transformations from urea to nitrate: CO(NH 2 ) 2 → 2NH 3 → 2NO 2 - → 2NO 3 - , however, at the same time, the wastewater from the grate to the discharge retains a high concentration of sodium chloride, which ends up in the rivers, and the concentration of which increases in river water by 5–10 times as the river flows from the source to the mouth. The effect of river bicarbonate dualism was established: the studied Eurasian plain rivers were divided into two groups according to the content of bicarbonate ions: the concentration of [HCO 3 ] - in river water is either – 3 mg-eq/dm 3 or 5 mg-eq/dm 3 , irrespective of the river scale, sampling location downstream, river geography and other factors.