| Printing and dyeing wastewater belongs to highly concentrated and difficultly degradable organic wastewater, which is difficult to be released up to standard by conventional biological treatment. After analyzing the character of printing and dyeing wastewater and the practical wastewater treatment technology route of a sewage disposal plant in Zhejiang Province, we bring forward the plan through which the technology route of "enhanced coagulation and sedimentation-Multi-stage anaerobic phases-cross flow aerobic sludge reactor" is utilized to treat this kind of wastewater.This paper employs enhanced coagulation and sedimentation-Multi-stage anaerobic phases-cross flow aerobic sludge reactor to treat printing and dyeing waste water, and the findings of the experiment shows that the process of this reactor is technically feasible, and can be operated stably. In enhanced coagulation and sedimentation tank, the average removal rate of COD,BOD,SS and Color are 45%,16.6%,61% and 40%, respectively, while the influent B/C is about 0.29 and the effluent B/C is up to 0.44, this biochemical properties of the waste water has been improved to some extent, which is useful for the subsequent biochemical treatment. Under the conditions of Multi-stage anaerobic phases reactor without the pH control, the average removal rate of COD,BOD,SS and Color are 14.6%,3.8%,10% and 25%, respectively, while the influent B/C is about 0.52 and the effluent B/C is so far as to to 0.74, biochemical properties has been further improved, which is conducive to the following aerobic biological treatment. The operation effect of pilot scale aerobic reactor in series with Multi-stage anaerobic phases reactor is examined, and results show:the variation range of pilot scale aerobic influent COD is 655-1023 mg/L, that of effluent COD is 79-191 mg/L and the average COD removal rate is 81.6%; but the aerobic effluent COD is lasts higher than 100 mg/L sometimes because of the higher sludge loading and the lower sludge concentration, proper control of sludge concentration or HRT, the effluent COD can be less than 100 mg/L; Influent BOD is usually 311～636 mg/L, effluent BOD is less than 15 mg/L, and the average BOD removal rate is larger than 97%; In addition, the average removal rate of TN,TP, NH4+-N,SS and Color are 80%,63%,90%.67% and 64.5%, respectively. The above-mentioned data indicate that the effluent can meet discharge criteria.Taking ADM1 proposed by the International Water Associations (IWA) Task Group for mathematical modelling of anaerobic digestion processes, established a mathematical model of Multi-stage anaerobic phases reactor treating dyeing and printing wastewater, so as to design, optimal operation, to provide a theoretical basis for prediction and control this kind of the water treatment plant. The simulation results based on ADM1 show that the larger difference between measured and simulated values of effluent COD exist in the first compartment of the reactor, the relative deviation is-16.2%～25.2%, but the third compartment, the fifth compartment and the seventh compartment all have better simulation, the relative deviations are-7.7%-20.0%,-6.4%-20.3%,-7.2%-18.6%, respectively. In addition, the modeling also shows better simulation results for VFA,MLVSS and pH。... |
PDF Full Text Request