There is recent trend of providing additional treatment of wastewater beyond tertiary level. The purpose is to refine water to a quality that is safe for reuse for unrestricted irrigation and other non potable uses. F...There is recent trend of providing additional treatment of wastewater beyond tertiary level. The purpose is to refine water to a quality that is safe for reuse for unrestricted irrigation and other non potable uses. For this purpose, Kuwait has built and operated an advanced wastewater treatment plant with capacity of 500,000 m3·dl. This plant providing treatment beyond tertiary utilizes the process of Ultra Filtration （UF） and Reverse Osmosis （RO）. The reject water of this unit contains high concentration of total nitrogen and total phosphate. Safe disposal of this water into the environment or possible reuse needs substantial reduction of these chemicals. In this study, a bench scale up-flow sludge blanket filtration system was investigated. The system operated with an average Hydraulic-Retention Time （HRT） of 19 h, whereas, sludge age varied within the range of 14 days to 16.5 days. The results show that the average removal efficiencies of the system for Biological Oxygen Demand （BOD）, Chemical Oxygen Demand （COD） were over 86% and 82% respectively. The phosphate and nitrogen＇s average removal were found to be 50% and 45% respectively.展开更多
The mesoporous Al-SBA-15 zeolite was obtained via impregnation of pure silica-based SBA-15 zeolite with aluminum nitrate.The Al-SBA-15 sample was calcined in air at 800 ℃ for 6 h and hydrothermally treated at near 1...The mesoporous Al-SBA-15 zeolite was obtained via impregnation of pure silica-based SBA-15 zeolite with aluminum nitrate.The Al-SBA-15 sample was calcined in air at 800 ℃ for 6 h and hydrothermally treated at near 100 ℃ for 120 h,respectively,and then the thermal and hydrothermal stability of Al-SBA-15 sample was investigated by X-ray diffractometry (XRD),scanning electron microscopy (SEM),transmission electron microscopy (TEM) and nitrogen adsorption and desorption techniques.The Al-SBA-15 sample was also studied by 27 Al nuclear magnetic resonance (27 Al NMR) and ammonia temperature programmed desorption (NH 3-TPD) techniques.In addition,the catalytic activity of Al-SBA-15 zeolite was investigated by the Friedel-Crafts reactions of 2,4-di-tert-butylphenol with cinnamyl alcohol.The test results showed that the thermal and hydrothermal stability of Al-SBA-15 zeolite was better than that of SBA-15 zeo-lite.The Al-SBA-15 zeolite sample prepared by impregnation method exhibits more framework aluminum species and Al-O-Si units.Therefore,the number of the surface hydroxyl groups was reduced,resulting in the stabilization of framework structure ofAl-SBA-15 zeolite.The aluminum species can form weak and medium-strong acid sites with catalytic activity.展开更多
文摘There is recent trend of providing additional treatment of wastewater beyond tertiary level. The purpose is to refine water to a quality that is safe for reuse for unrestricted irrigation and other non potable uses. For this purpose, Kuwait has built and operated an advanced wastewater treatment plant with capacity of 500,000 m3·dl. This plant providing treatment beyond tertiary utilizes the process of Ultra Filtration （UF） and Reverse Osmosis （RO）. The reject water of this unit contains high concentration of total nitrogen and total phosphate. Safe disposal of this water into the environment or possible reuse needs substantial reduction of these chemicals. In this study, a bench scale up-flow sludge blanket filtration system was investigated. The system operated with an average Hydraulic-Retention Time （HRT） of 19 h, whereas, sludge age varied within the range of 14 days to 16.5 days. The results show that the average removal efficiencies of the system for Biological Oxygen Demand （BOD）, Chemical Oxygen Demand （COD） were over 86% and 82% respectively. The phosphate and nitrogen＇s average removal were found to be 50% and 45% respectively.
文摘The mesoporous Al-SBA-15 zeolite was obtained via impregnation of pure silica-based SBA-15 zeolite with aluminum nitrate.The Al-SBA-15 sample was calcined in air at 800 ℃ for 6 h and hydrothermally treated at near 100 ℃ for 120 h,respectively,and then the thermal and hydrothermal stability of Al-SBA-15 sample was investigated by X-ray diffractometry (XRD),scanning electron microscopy (SEM),transmission electron microscopy (TEM) and nitrogen adsorption and desorption techniques.The Al-SBA-15 sample was also studied by 27 Al nuclear magnetic resonance (27 Al NMR) and ammonia temperature programmed desorption (NH 3-TPD) techniques.In addition,the catalytic activity of Al-SBA-15 zeolite was investigated by the Friedel-Crafts reactions of 2,4-di-tert-butylphenol with cinnamyl alcohol.The test results showed that the thermal and hydrothermal stability of Al-SBA-15 zeolite was better than that of SBA-15 zeo-lite.The Al-SBA-15 zeolite sample prepared by impregnation method exhibits more framework aluminum species and Al-O-Si units.Therefore,the number of the surface hydroxyl groups was reduced,resulting in the stabilization of framework structure ofAl-SBA-15 zeolite.The aluminum species can form weak and medium-strong acid sites with catalytic activity.
