الفهرس 
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Abstract
This study investigates the potential of using nanoparticles in the wastewater treatment technology either for industrial wastewater (i.e., dyes) or domestic wastewater (i.e., sewage sludge). The selected nano particles are magnetite, carbon nano tubes and composite of them. Advanced oxidation process was adopted for the treatment of dyes via Fenton and photo-Fenton process. On the other hand, anaerobic digestion process was applied for the purification of sewage sludge. Results of Fenton-like process revealed that 50 minutes is the adequate time for the complete decomposition of methylene blue dye when pH was 34 and the concentration of Fe3O4.CNTs was 0.75 g/L. The removal rate increased from 95% 98% when the nano dose augmented from 0.5 to 0.75 g/L, respectively. This was due to the existence of active sites in the solution which leads to increase the efficiency of the process. The removal rate incremented when the hydrogen peroxide dose increased from 1 to 2 g/L by 83 to 99%, respectively due to the availability of hydroxyl radicals coming from the reaction of hydrogen peroxide with iron ions. Furthermore, results of the photo Fenton process at the same conditions of the Fenton-like process showed a complete decomposition of the methylene blue dye due to presence of light that promotes the conversion of Fe3+ to Fe2+ and produce more hydroxyl radicals that enhanced the degradation of the methylene blue dye. Durability of using these nanoparticles in the classical Fenton like reaction via cyclic reactions, in which the removal efficiency reduced from 98% to 90% in the second cycle. The removal efficiency, however, was further decreased in the third and fourth cycles to 78%. The decrease in active sites of nanoparticles was the reason of removal efficiency deterioration. In photo Fenton process, ABSTRACT iii the removal percentage decreased from 100% at the 1st cycle to 99, 97 and 94% at the 2nd, 3rd, and 4th cycles, respectively. This study also presented the treatment of wastewater sludge via dark fermentation process amended with nanoparticles. The optimal dose of these nanoparticles that achieve the highest removal percentage of organic matter as well as the highest production of biogas was determined. The results showed that limited degradation efficiency of 27.5 ± 3.8% registered at the reactor is not supplied with nano particles. However, this value was augmented to 48.6 ± 5.9% and 45.8 ± 4.8% when adding 200 mg/L of Fe3O4 NPs and 300 mg/L MWCNTs, respectively. Maximum removal efficiency of 27.5 ± 3.8% was acquired when the reactor supplied by 200 mg/L Fe3O4-MWCNTs composite. On the other hand, removal percentage is reduced to 26.3 ± 3.2, 33.9 ± 4.7 and 30.8 ± 3.9% when batches were supplemented with 500 mg/L of Fe3O4, multi wall carbon nano tubes and magnetic multi wall carbon nano tubes respectively, due to the harmful effect on anaerobic digestion.