Iron salt based flocculant for waste waters or sludges - contains soluble salt additive e.g. Gp=II metal salt

摘要

Flocculant for purifying residual or waste water or sludges, contg. Fe, in the form of FeCl3, Fe(SO4)Cl, FeSO4 and/or FE2(SO4)3, is improved by incorporating an additive comprising a salt which is soluble in the medium and which is a salt of a gp IIA metal, Al, ZN, Cu or MN. Pref. additives are Mg and/or Al chloride, nitrate or acetate and nitrates of alkaline earth metal, Cu and Zn.