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Defluoridation of drinking water by hybrid coagulation and filtration process ; Fluoridentfernung von Trinkwasser mit Hybrid Koagulation und Filter-verfahren
Fluoride contamination in drinking water can cause severe health problems, namely fluorosis. Defluoridation of drinking water is a practical option to overcome the problem of excessive fluoride in drinking water. Considering that most affected regions are located in less developed countries, it is necessary to find a safe and inexpensive defluoridation technique in order to remove the excess fluoride from drinking water. This study proposes two hybrid methods that have not been investigated with emphasis not only on the fluoride removal but also on the removal of the aluminum residue in the product water. The first step of the hybrid process is based on coagulation and co-precipitation based on Nalgonda technique. Alum (Al2(SO4)3) is used as coagulant, while lime (Ca(OH)2) accounts for maintaining the system pH and as precipitation agent. However, the drawback of this process is a significant aluminum level in the product water. A systematic process study has shown that the removal of fluoride occurred very fast. It was best carried out at neutral pH and with an excessive amount of aluminum coagulant. Fluoride ions were adsorbed by precipitated aluminum hydroxide. After certain time the precipitated aluminum hydroxide collided and enmeshed fine particles and later settled down. It is suggested that the removal reaction follows a sweep mechanism. Furthermore, to decrease fluoride concentration to the desired concentration, the optimum alum dosing was successfully determined. Reduction of fluoride concentration from an initial concentration of 10 mg/L to below 1.5 mg/L was best at an aluminum dosing of 100 mg/L that is corresponding to an Al3+ to F- molar ratio ≥ 7. Meanwhile, for fluoride with initial concentration of 4 mg/L, an Al3+ to F- molar ratio ≥ 4, equal to 17 mg/L aluminum, achieved the same purpose. This amount of aluminum is clearly lower than needed in the Nalgonda technique which is 16 to 181 mg/L or treating raw water with fluoride levels of 2 to 8 mg/L. Lower amounts of aluminum are preferred to ...
Defluoridation of drinking water by hybrid coagulation and filtration process ; Fluoridentfernung von Trinkwasser mit Hybrid Koagulation und Filter-verfahren
Fluoride contamination in drinking water can cause severe health problems, namely fluorosis. Defluoridation of drinking water is a practical option to overcome the problem of excessive fluoride in drinking water. Considering that most affected regions are located in less developed countries, it is necessary to find a safe and inexpensive defluoridation technique in order to remove the excess fluoride from drinking water. This study proposes two hybrid methods that have not been investigated with emphasis not only on the fluoride removal but also on the removal of the aluminum residue in the product water. The first step of the hybrid process is based on coagulation and co-precipitation based on Nalgonda technique. Alum (Al2(SO4)3) is used as coagulant, while lime (Ca(OH)2) accounts for maintaining the system pH and as precipitation agent. However, the drawback of this process is a significant aluminum level in the product water. A systematic process study has shown that the removal of fluoride occurred very fast. It was best carried out at neutral pH and with an excessive amount of aluminum coagulant. Fluoride ions were adsorbed by precipitated aluminum hydroxide. After certain time the precipitated aluminum hydroxide collided and enmeshed fine particles and later settled down. It is suggested that the removal reaction follows a sweep mechanism. Furthermore, to decrease fluoride concentration to the desired concentration, the optimum alum dosing was successfully determined. Reduction of fluoride concentration from an initial concentration of 10 mg/L to below 1.5 mg/L was best at an aluminum dosing of 100 mg/L that is corresponding to an Al3+ to F- molar ratio ≥ 7. Meanwhile, for fluoride with initial concentration of 4 mg/L, an Al3+ to F- molar ratio ≥ 4, equal to 17 mg/L aluminum, achieved the same purpose. This amount of aluminum is clearly lower than needed in the Nalgonda technique which is 16 to 181 mg/L or treating raw water with fluoride levels of 2 to 8 mg/L. Lower amounts of aluminum are preferred to ...
Defluoridation of drinking water by hybrid coagulation and filtration process ; Fluoridentfernung von Trinkwasser mit Hybrid Koagulation und Filter-verfahren
2017-06-14
Theses
Electronic Resource
English
Defluoridation of drinking water by hybrid coagulation and filtration process
| UB Braunschweig | 2017
Defluoridation of Drinking Water in Southern California
| Wiley | 1965
| British Library Conference Proceedings | 2012