[en] The invention concerns to process of industrial sewage cleaning from chromium and as well as chromium regeneration with purpose of the subsequent use during tanning process. It could find application in tanning manufacture, non- ferrous metallurgy, during processing metals. The aim of invention is increase of degree and rate of cleaning, improvement of quality of formed precipitate and maintenance of an opportunity of repeated magnesium oxide use during cleaning. The process of sewage deep cleaning from chromium (III) includes processing by magnesium oxide and separation of precipitate with regeneration of chromium. The processing has been conducted by 50-150% surplus of magnesium oxide with precipitate separation, its dissolving in an acid and processing by alkali up to pH 9,0-9,5. Then the formed chromium containing precipitate is separated. The solution is alkaloids up to pH 11,5 and precipitate-containing magnesium is separated