الفهرس 
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Abstract
Drinking Water treatment plants generate large quantities of sludge as a by-product of the treatment process (10% per day). Recently, sludge has been treated as a waste disposed in landfills, which increases the environmental burdens and the operational cost. Therefore, sludge reusing becomes a significant environmental issue. The objective of this work is to attempt to improve, Preservation and optimization of sludge produced from water purification plants. The first part of this research purposed to examine the impacts of recycling supernatant from drying beds (SDB) and filter backwash water (BWW) to the inlet of drinking water treatment plant (WTP), and its effect on both removal efficiency of turbidity and decreasing alum dosage used in WTP. The results obtain revealed that, recycling of 12.5 % BWW gave 96.1% removal efficiency of turbidity and decrease alum dosage from 20 to 18 mg/l. Moreover, recycling 10% of combined BWW: SDB with ratio of 80:20 showed 95.3% removal efficiency of turbidity and decrease alum dosage from 20 to 18 mg/l. This finding attributed to the remaining amorphous aluminum in the sludge, which has a significant role in saving alum dosage used in WTP. And also to the high turbidity of BWW, which supports the theory of additional turbidity into the raw water that may have increased the number of collision sites available during the flocculation process. The second part of this work, adsorption of copper ions (Cu2+) onto calcined sludge was investigated under various operational conditions (temperature, Cu2+ initial concentration, pH, and sludge dosage). The prepared sludge material was characterized by transmission electron microscope, X-ray diffraction, dynamic light scattering, and BET surface area. The sorption capacity of sludge was directly related to the initial Cu2+ concentration and inversely related to sludge dosage. The optimum operational pH and solution temperature were 6.6 and 80 °C, respectively. The experimental results followed Langmuir isotherm and pseudo -first order adsorption kinetics. Thermodynamic parameters such as activation energy, change in free energy, enthalpy and entropy were calculated. Thermodynamic analyses indicated that the sorption of copper ions onto the calcined sludge was derived by a physical adsorption process. The prepared sludge was proven to be an excellent adsorbent material for Cu2+ from aqueous solution under optimum conditions.