WASTE WATER NEUTRALIZATION AND CLEANING PROCESS Russian patent published in 2001 - IPC

FIELD: waste water treatment. SUBSTANCE: invention, in particular, relates to treatment of waste waters to remove heavy metal ions of one type and at high concentration. Treatment is performed in two steps. In the first step, waste water is treated with alkalipeat reagent at weight ratio of one-type alkali metal ions to reagent 1:(1- 1.3), alkali-peat reagent, more specifically, being sodium hydroxide filtrate solution passed through peat granules. Treated waste water is agitated and settled to reach pH 6,4-6.95, after which, in the second step, treated with lime milk to pH 8,75- 9,25, agitated and settled to separate precipitate, and finally decolorized. Peat granules are pretreated advantageously with 0.1 n hydrochloric acid solution and then with 0.1-1 N sodium hydroxide solution until saturation of peat granules with sodium ions is completed. Decoloration operation is accomplished by two-step coagulation with aluminum-containing coagulants plus flocculant followed by settling, separation of precipitate, and filtration. Double-step ozonation followed by sorption is also effective to achieve decoloration. EFFECT: increased degree of cleaning at reduced consumption of alkali reagents. 4 cl, 1 tbl, 2 ex