الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Sedimentation is one of the most commonly used units in water and wastewater treatment plants. Conventional sedimentation tanks suffer from overloading problems which result in poor performance. Lamella plates and tube settlers, may contribute in upgrading sedimentation tanks. This study aimed to evaluate the efficiency of using lamella plates and tube settlers in clarifiers in comparison with pulsator clarifiers and square clariflocculators within WTPs (water treatment plants) located in Cairo and Giza governments in Egypt. A comparison was done during the period of winter and summer 2015. The evaluation was done on the basis of removal efficiency of turbidity, bacteria and algae. The results have shown that tube settler clarifiers are more efficient than lamella plate clarifiers and other clarifying systems with higher SLR (surface loading rates). Application of these plates has not caused any interruption of daily operation of treatment plants and could be achieved at minimal cost. Results indicated that the tube settler clarifiers have achieved the highest removal efficiency in terms of turbidity, bacteria and algae. Tube settler clarifiers recorded 86.80% and 86.31 % as average turbidity removal efficiency during summer and winter respectively so it is better than the efficiency of Lamella plate clarifiers which equal to 74.11 % and 69.59 % in summer and winter respectively. The efficiency of the tube settler and lamella plate clarifiers in removing the bacteria and the algae is very good and it is approximately equal to it for the other sedimentation systems such as Pulsator clarifiers and the Square Clariflocculators (higher than 90 %) although they have a higher surface overflow rate than it for Pulsator clarifiers and the Square Clariflocculators.