LEATHER PRODUCTION WASTE WATER TREATMENT PROCESS Russian patent published in 2000 - IPC

FIELD: leather industry. SUBSTANCE: aluminum sulfate is mixed with waste water originally containing much suspended particles and fats and subjected to removal of coarse solids. Coagulation is then carried out at constant concentration of fine solids (3500-3600 mg/l), pH 6.5-7.4, and aluminum sulfate concentration 12-20 mg/l. Precipitate is separated under the same conditions. Constant concentration of fine solids is maintained by returning treated waste water into the mixing process. Treatment is continued until concentration of suspended solids 140 mg/l is attained. EFFECT: enabled controlling subsequent biochemical purification and more than 40-fold reduced consumption of aluminum sulfate. 2 cl, 1 tbl