| Nitrogen(N) and Phosphorus(P) in receiving water body have caused many problems on the river and estuary, such as eutropication, red tide and aquatic toxicity. Therefore, the effective N and P removal from wastewater treatment plants is necessary to prevent those pollution problems. However, a few wastewater treatment plants in Korea are effectively being operated for the removal of the nutrients. This study, therefore, was conducted to investigate the how to improve the conventional wastewater treatment plants for further removal of organic materials and nutrients, such as N and P. The experiments on the effective removal of the organics and nutrients in the influent from the J wastewater treatment plant, which is a conventional wastewater treatment plant being operated in Pusan city, were carried out using several treatment processes, including chemical treatment, Anoxic/Oxic process, and conventional activated sludge process. When the chemical treatment was applied with a coagulant dosage of 40 ㎎/ℓ as FeCl₃. the removal efficiencies of COD, SS, and PO₄-P were 57.75%, 90.43%, and 73%, respectively. Overall the Anoxic/Oxic system using the coagulant, was much better than conventional activated sludge process regardless of in aspect of removing the nutrients. In comparing of the nitrogen removal efficiency by the Anoxic/Oxic system, applying chemical treatment following the Anoxic/Oxic system was much better than applying the Anoxic/Oxic system alone. Also, the N removal efficiency by Anoxic/Oxic system was increased as the inner recycle ratio increased from 70% to 100%. Also, in proportion to the increased of inner recycle ratio, that is 70%∼300%, Nitrogen removal efficiencies are effective in Anoxic/Oxic system. |
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