METHOD OF BIOLOGICALLY CLEANING WASTE WATERS TO REMOVE ORGANICS AND NITROGEN Russian patent published in 2003 - IPC

FIELD: waste water treatment. SUBSTANCE: streams of ammonium- and nitrate-containing sewages (from chemical or fertilizer production enterprises, cattle-breeding farms, or domestic-origin sewages) are fed into anaerobic denitrification process, which functions at specific rate 3.2-4.5 mg/g.h. Resulting water is passed into aerobic process, wherein denitrification is accomplished at specific rate 1.2-2.0 mg/g.h. Nitrate-containing stream and separated sludge are recycled from aerobic to anaerobic process, while quantitative ratio of recycled nitrate-containing stream to overall water stream is maintained between 3:1 and 5:1. Amount of oxygen in anaerobic stage is maintained below 0.5 mg/l and that in aerobic stage below 2 mg/l. EFFECT: enhanced cleaning degree and simplified process. 1 tbl, 3 ex