The concns. of ibuprofen in untreated and treated wastewaters and in water originating from sludge dewatering were detd. by chromatod. for 3 months 2015 (av. values 12, 0.2 and 6.2 mg/L, rasp.). In addn. respiration activity of mixts. contg. 8 mL active sludge and various concns. of ibuprofen was detd. by using an O probe. A 50% redn. in biol. O demand by microorganisms in sludge was achieved for concns. of ibuprofen 830 mg/L.