Wastewater treatment process to improve denitrification while dephosphating

摘要

Use of a metal salt of formula (I), in the form of an aqueous solution or suspension, to improve denitrification with simultaneous dephosphation in the treatment of sewage and/or industrial waste liquor, is new. Mea(III)Meb(II)(OH)cXdRe (I) Me(III) = Al or Fe; Me(II) = Fe, Ca or Mg; X = Cl, SO4 or NO3; R = formate, acetate, oxalate, propionate, tartrate, lactate, maleate and/or citrate; a = 0-1; 3(a+2).b = 3; c = 0-2.5 (preferably 0-1.5); d = 0-2.95/z; z = number of negative charges of the anion; e = 0.05-3/y; y = number of acid functions of the acid HyR corresponding to R; and c+d/z+e/y = 3.