A shafttype activated sludge reactor has been developed with a view to improve the organics removal efficiency. It was added with (10 – 30) g/L tyre tube beads of average size 5 mm to make a hybrid system. The removal of organics in terms of Chemical Oxygen Demand (COD) and Biochemical Oxygen Demand (BOD5) was studied. The batch study with 1000 – 4000 mg/L of COD showed improvement in the sludge settleability. The values of Ks, k, Y and kd were measured as 298.59 mg/L, 0.113 h−1, 0.6397 kg MLSS/kg COD removed and 0.0025 h−1 respectively. The maximum COD removal efficiency was observed as 88% for an organic loading rate of 3.00 kg d−1m−3. The maximum BOD5 removal efficiency was attained as 89.2% for a loading rate of 2.71 kg d−1m−3. The Maximum value of substrate utilization coefficient for synthesis and endogenous respiration was observed as 0.852 h−1 and 0.0198 h−1 respectively.
Hybrid activated sludge, shafttype reactor, high organics, tyretube beads, COD, BOD5
