Chemical Industry and Chemical Engineering Quarterly (Sep 2008)
THE EFFECT OF THE SLUDGE RECYCLE RATIO IN AN ACTIVATED SLUDGE SYSTEM FOR THE TREATMENT OF AMOL'S INDUSTRIAL PARK WASTEWATER
Abstract
An activated sludge aeration tank and a sedimentation basin were used to treat Amol’s industrial park effluents originating from all industrial units. A continuous system was implemented and the kinetic parameters were measured.The parameters such as rate constant, substrate utilization rate constant, yield and decay coefficient were 2.12 d-1, 232.4 mg l-1, 0.33 g/g of substrate and 0.096 d−1, respectively. The hydraulic retention times (HRT) were in the range of 9 to 27 h. The sludge recycle ratios in the range from 0.3 to 1 were considered. The COD removal, SVI and DO were determined and the optimal values were obtained. It was observed that at HRT of 16 h and the sludge recycle ratio of 0.85, the COD removal and SVI were 95 and 85 %, respectively. The sludge recycle ratio greater than 0.85 had no significant effect on the COD removal.
