| Printing and dyeing wastewater is one of the industrial wastewater which are most difficult to deal with in the world as we all know, most research focused on how to carry out advanced treatment and reuse of printing and dyeing wastewater effectively.Advanced treatment of the integrated membrane was an important method in industrial wastewater reusing in recent years, which was extensively developed in printing and dyeing wastewater advanced treatment. With characters of easy construction, significant effect, stable quality of produced water and90%desalination rate by reverse osmosis, membrane technology combined other methods expand the application of the printing and dyeing wastewater advanced treatment. In order to make the printing and dyeing wastewater satisfy the discharge standard, and provide new solution to achieve energy conservation and emissions reduction in printing and dyeing advanced treatment,we use microfiltration and reverse osmosis integrated technology to treat the biochemical process in printing and dyeing wastewater, based on the produced water quality treated by double membranes method, the operating condition and cleaning of reverse osmosis were optimized.It’s feasible using microfiltration as pretreatment of reverse osmosis, the turbidity and SDI (silting density index) of produced water by microfiltration are0.1NTU and4, respectively, which satisfy the requirement of feed water quality of reverse osmosis. Meanwhile, microfiltration has an advantage of low operative pressure and energy conservation.Printing and dyeing wastewater after biochemical process was treated through MF-RO double membranes, the removal rates in turbidity, chroma, electrical conductivity, CODcr, Cr6+and NH3-N of produced water achieved above94%. The concentration SO42-, Cl,Cr6+and NH3-N in produced water are1.8,12.8,0.8,0and 0.8mg·L-1, respectively, the CODcr less than10mg·L-1, the produced water quality satisfy the standard of the produced water quality satisfy the standard of ((Technology standard treatment engineering of water pollutants for dyeing and finishing of textile industry》 HJ471-2009, and can be reused.We selected static simulation test to optimize the experimental conditions of biochemical process which used to treat printing and dyeing wastewater, after assumed by orthogonal test and single factor experiment, we get the optimized conditions with operative pressure0.8Mpa, water temperature35℃, pH6.0-10.0and recovery rate80%using MF-RO double membranes method.Through the different kinds of salt without the same concentration and different concentrations of the same salt contrast test analysis, Feed water without the same concentration containing NaCl was easier desalinized than that of Na2SO4,And the high concen-tration was better than low concentration of salt water desalination rate.There is a linear correlation between desalination rate and CODcr removal percentage of reverse osmosis and feed water pressure, produced water quality improved with increasing operative pressure. Increase the temperature of feed water can reduce viscosity and intensify turbulent motion, membrane flux increased as a result, but coupling salt transit dose increased at the same time which influenced treat effect. Change pH of feed water has no benefit on treat result, and if the pH exceed the limit of membrane performance, it will lead to membrane fouling even damage and it’s bad for installations’safety and economy.In the simple physical cleaning process,Cleaning fluid temperature with impro-veing can improve the recovery of membrane flux, but the cleaning effect is not very good.For the chemical cleaning,Main consideration were oxidizing and alka-line agents to clean. Agents cleaning sequence and a mixed concentration have certain influence on cleaning effect. Comprehensive analytical, It’s much better with mixed medicament one-time cleaning for the experiment suggestion. It’s suggested to mix1%NaCIO+2%NaOH+0.1%ETDA-2Na for one-time cleaning... |
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