Membrane fouling is the main problem of membrane bioreactors (MBR), which seriously influ- ences its wastewater treatment effect and running. The characteristics of microbiology and hydrodynamics concerning membrane f...Membrane fouling is the main problem of membrane bioreactors (MBR), which seriously influ- ences its wastewater treatment effect and running. The characteristics of microbiology and hydrodynamics concerning membrane fouling were investigated and the measure was put forward for optimum operation of MBR. The measure is that 1) the parameters of activated sludge concentration (X) and membrane flux should be lower than the critical values of X and membrane flux respectively, and 2) the activated sludge should be discharged periodically. The experimental results show that the combination backwashing of gas and perme- ated effluent is better than single gas backwashing or single permeated effluent backwashing. This technique can remove the cake layer deposited on the membrane surface, decrease the membrane fouling, and recover the membrane flux effectively. So it is effective for prevention of membrane fouling.展开更多
The reverse osmosis method is one of the most widely used methods of seawater desalination at present.Hydrophilic and desalting membranes in reverse osmosis systems are highly susceptible to the input pollutants.Vario...The reverse osmosis method is one of the most widely used methods of seawater desalination at present.Hydrophilic and desalting membranes in reverse osmosis systems are highly susceptible to the input pollutants.Various contaminants,including suspended organic and inorganic matter,result in membrane fouling and membrane degradation.Fundamental parameters such as the turbidity,the amount of chlorine injection,and silt density index (SDI) are the most predominant parameters of fouling control in the membranes.In this study,the operation system included a water intake unit,a pretreatment system,and an RO system.The pretreatment system encompassed a clarifier,a gravity sand filter,pressurized sand filters,and a cartridge filter.The correlation between the amount of chlorine injection in terms of the oxidation-reduction potential (ORP) and the SDI value of the input water was investigated at a specified site next to the Persian Gulf.The results showed that,at certain intervals of inlet turbidity,injection of a certain amount of chlorine into the raw water has a distinct effect on the decrease of SDI.展开更多
在超滤前进行混凝预处理可以减轻膜污染,混凝/超滤组合工艺已得到广泛的认可。在混凝/超滤工艺中引入曝气,形成了混凝/气提/超滤组合水处理新工艺。通过试验分析不同曝气量条件下的跨膜压差(TMP)、膜污染总阻力(Rt)以及膜污染指数(UMFI)...在超滤前进行混凝预处理可以减轻膜污染,混凝/超滤组合工艺已得到广泛的认可。在混凝/超滤工艺中引入曝气,形成了混凝/气提/超滤组合水处理新工艺。通过试验分析不同曝气量条件下的跨膜压差(TMP)、膜污染总阻力(Rt)以及膜污染指数(UMFI),探讨了不同曝气量下的膜污染情况。结果表明,混凝和曝气有利于减轻膜污染;并且随着曝气量的增加,TMP和Rt增长速率呈降低的趋势,UMFI值也逐渐减小。当曝气量从零增加到180 m L/min时,TMP和Rt的平均增长速率分别从0.211 k Pa/h和0.037×1012m^(-1)/h降低至0.065 k Pa/h和0.026×1012m^(-1)/h,UMFI值从0.001 18 m^2/L降低至0.000 30 m^2/L,膜污染程度显著降低。展开更多
文摘Membrane fouling is the main problem of membrane bioreactors (MBR), which seriously influ- ences its wastewater treatment effect and running. The characteristics of microbiology and hydrodynamics concerning membrane fouling were investigated and the measure was put forward for optimum operation of MBR. The measure is that 1) the parameters of activated sludge concentration (X) and membrane flux should be lower than the critical values of X and membrane flux respectively, and 2) the activated sludge should be discharged periodically. The experimental results show that the combination backwashing of gas and perme- ated effluent is better than single gas backwashing or single permeated effluent backwashing. This technique can remove the cake layer deposited on the membrane surface, decrease the membrane fouling, and recover the membrane flux effectively. So it is effective for prevention of membrane fouling.
文摘The reverse osmosis method is one of the most widely used methods of seawater desalination at present.Hydrophilic and desalting membranes in reverse osmosis systems are highly susceptible to the input pollutants.Various contaminants,including suspended organic and inorganic matter,result in membrane fouling and membrane degradation.Fundamental parameters such as the turbidity,the amount of chlorine injection,and silt density index (SDI) are the most predominant parameters of fouling control in the membranes.In this study,the operation system included a water intake unit,a pretreatment system,and an RO system.The pretreatment system encompassed a clarifier,a gravity sand filter,pressurized sand filters,and a cartridge filter.The correlation between the amount of chlorine injection in terms of the oxidation-reduction potential (ORP) and the SDI value of the input water was investigated at a specified site next to the Persian Gulf.The results showed that,at certain intervals of inlet turbidity,injection of a certain amount of chlorine into the raw water has a distinct effect on the decrease of SDI.
文摘在超滤前进行混凝预处理可以减轻膜污染,混凝/超滤组合工艺已得到广泛的认可。在混凝/超滤工艺中引入曝气,形成了混凝/气提/超滤组合水处理新工艺。通过试验分析不同曝气量条件下的跨膜压差(TMP)、膜污染总阻力(Rt)以及膜污染指数(UMFI),探讨了不同曝气量下的膜污染情况。结果表明,混凝和曝气有利于减轻膜污染;并且随着曝气量的增加,TMP和Rt增长速率呈降低的趋势,UMFI值也逐渐减小。当曝气量从零增加到180 m L/min时,TMP和Rt的平均增长速率分别从0.211 k Pa/h和0.037×1012m^(-1)/h降低至0.065 k Pa/h和0.026×1012m^(-1)/h,UMFI值从0.001 18 m^2/L降低至0.000 30 m^2/L,膜污染程度显著降低。
