Decolorization Of Alizarin Yellow R In Anaerobic And Bio-electrochemical Coupling System

Azo dye wastewater has the characteristics with high chroma, complicated composition, large emissions, and difficult bio-degradability, so it belongs to refractory industry waste water, the majority content of of this waste water is teratogenic, carcinogenic, mutagenic. If it enters into the environment, it may cause a serious threat to the ecosystem and health of human lives. The traditional treatment of azo dyes wastewater is physical, chemical and biological method, but these traditional porcesses have shortcomings, so we consider to combine biological electrochemical method with the traditional biological treatment method, so that we can achieve efficient result for azo dye wastewater treatment.This study selected alizarin yellow R(AYR) as target contaminant. First, we conduct the study of bio-electrochemical system without membrane to study the efficiency of it when treating AYR, investigating the influence of AYR concentration and applied voltage on dyes decolorizing efficiency. At the same time, we also exame the effect of AYR on the efficiency of anode. The results show that concentration of AYR and the applied voltage can influence the dyes decolorizing efficiency. When the concentration of AYR is 75 mg/L, the maximum decolorizing efficiency of the system is achieved. Applied voltage can promote the decolorization of AYR, at the same time, it can also maintain the activity of biofilm on anode, making the performance of reactor stable. The influence of of AYR on performance of anode in electrochemical system without membrane is in accordance with the decolorization of AYR.On this basis, in order to maintain biological activity and stability of anode and achieve better function of cathode of azo dye decolorization, we develop and build a sleeve type anaerobic biological-electrochemical system coupling device(AD-BES) with large size of 30 L. In the AD-BES, biological –electrochemical is above anaerobic sludge bed, at the same time. Anode is in the middle of cathode, separated with anion exchange membrane from anode. Anaerobic sludge zone and cathode zone is connected, and anode is controlled alone. There are two groups of electrodes(1 # and 2 #) in the biological electrochemical district. The azo dye wastewater is treated by using the device, in the condition of intermittent and continuous running respectively. The results show that when HRT is 12 h and azo dye load is 140 g/m3?d, the decolorization ratio of AYR is as high as 93.2±2.2%, significantly higher than the pure anaerobic AD process(85.1± 0.7%), andthe maximum removal rate of AYR is 264 g/m3?d. The introduction of biological electrochemical system can promote the further removal of anaerobic biological process for dye, BES contributes up to 10.5% for removal of dye. The addition of electrochemical module can also enhance the removal efficiency of COD. This study confirmes that the effective feasibility of the couple modle of anaerobic and biological electrochemical process.