| Printing and dyeing wastewater treatment has always been a difficult problem in the world,printing and dyeing wastewater because of its large emissions,poor biochemical properties,complex composition and other characteristics resulting in a sharp increase in processing difficulties.With the rapid development of China’s economy,the demand for printing and dyeing industry is increasing,but the current situation of lack of water resources has led to the development of printing and dyeing industry,printing and dyeing wastewater treatment becomes more and more important,the traditional single water treatment technology can not meet the discharge standards of printing and dyeing wastewater.Membrane separation technology is a fast,environmentally friendly and efficient method,the use of membrane separation technology in the actual project effluent water quality is good,which for the future treatment of printing and dyeing wastewater to provide a new treatment direction.In this paper,electrolysis as pretreatment and dynamic membrane bioreactor(DMBR)is used to treat simulated printing and dyeing wastewater,and to study the effect of electrolysis on the removal efficiency of various pollutants and the control of membrane fouling.In this experiment,methyl orange with typical azo dye structure was used as experimental object,the electrode material,current density,electrolytic time and plate spacing were used as experimental factors in orthogonal experiment,and the influence of plate material,current density,electrolytic time and plate spacing on electrolytic treatment simulated dyeing wastewater was determined by orthogonal test and extreme difference method.Combined with single factor test,the optimum condition of selecting activated carbon fiber plus iron as plate,current density is 10mA·cm2,electrolytic time is 60 min,plate spacing is taken 2cm.Under the optimal electrolytic reaction conditions,by comparing the electrolytic pretreatment with the DMBR process and the removal efficiency of the single DMBR process,the effects of electrolysis on the pollution indexes and membrane pollution control in simulated printing and dyeing wastewater were analyzed,the results showed that the COD removal rate of the combined DMBR and electrolytic pretreatment was not much different from DMBR.However,the average removal rate of chroma and ammonia nitrogen increased by 21% and 4.5% respectively.After reading the literature,it was found that the mechanism of removing chroma was destroying the azo bond in methyl orange.The three-dimensional fluorescence spectra show that the DOM fluorescence peaks in the wastewater are constantly changing in the process of electrolysis and electrolytic binding DMBR,that is,the substance and functional group species change.Electrolysis can improve the biodegradability of wastewater,and decompose macromolecular aromatic compounds into small molecule organics,which can improve the efficiency of DMBR process to simulate printing and dyeing wastewater.But in the membrane pollution control aspect,the extracellular polymer content,the Zeta potential,the membrane flux and the membrane resistance change amplitude,the particle diameter is smaller than the 10μm proportion,the viscosity is smaller than the individual DMBR craft in the electrolytic-A/O-DMBR process.The main cause of membrane fouling by Fourier infrared spectroscopy is protein and polysaccharide,and the content of protein and polysaccharide in DMBR process is more than that in electrolytic-A/O-DMBR,it can be verified that electrolytic pretreatment can effectively delay membrane fouling. |
