| Popis: |
Due to the recent climatic and economic developments in the Middle East, the region has become on the verge of water poverty. It has become imperative to reconsider the policy of water spending and rationalization of consumption and to consider recycling all types of water, thus in this study, two identical stages of the RBCs system were used to treat wastewater after its primary treatment at Zenin wastewater treatment plant in Giza, Egypt. Different materials were used in the treatment process such as geotextile, (in two different forms), circular discs and discs in the form of gear, with 15 discs per RBC stage, a steel cylinder, in addition to a plastic bottle with holes with sugarcane straw inside. The rotation speeds were varied between 5, 8 and 10 RPM, with 40% submergence for the geotextile discs of the normal circular shape and for the rest of the materials a rotation speed of 5 RPM were used, where it was found later that it gave the best results. The hydraulic retention time ranged between one, two, and three up to seven days. It was found that the best results obtained at HRT of 3 days. Results showed that the removal rates of BOD, COD and TSS were almost 82%, 86.7% and 81.5% at 5RPM for normal circular discs shape respectively, while for gear shaped discs removal rates were almost 83.7%, 91% and 81.3% respectively. For sugarcane straw plastic bottle, BOD, COD and TSS removal rates were almost 64.86%, 69.49 and 68.18% at 5RPM respectively, noting that sugarcane straws removal rates were the lowest among the rest of materials. Removal rates were almost 86.9%, 94.4 and 82.14% for BOD, COD and TSS respectively at 5RPM for steel cylinder. Steel cylinder showed the highest removal rates among all other materials. |
