| URN | etd-0717118-122537 | Statistics | This thesis had been viewed 179 times. Download 2 times. |
| Author | KAO-JUNG CHEN | ||
| Author's Email Address | mickey0916160588@gmail.com | ||
| Department | Department of construction & spatial design | ||
| Year | 2017 | Semester | 2 |
| Degree | Master | Type of Document | Master's Thesis |
| Language | zh-TW.Big5 Chinese | Page Count | 52 |
| Title | Assessment of nitrogen and phosphorus removal efficiency of A2O biological treatment process in sewage treatment plant -A case study of a water reclamation center in the north |
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| Abstract | The aim of this study was to examine the efficiency of nitrogen and phosphorus removal based on 10,000 cubic meters per day (CMD) of wastewater flow rate at a water reclamation center in northern Taiwan. Due to the supernatant containing high orthophosphate levels from the sludge thickening tank, it led to excessive phosphate returning to the primary settling tank from the waste liquid tank. Through a modified method of removing the supernatant in the sludge thickening tank, the orthophosphate concentration from the outlet of primary settling tank decreased from 10- 16 mg/L to 5.8- 7.0 mg/L. In addition, a synergistic effect was obtained with the method of chemical phosphorus removal, this achieved the effluent standards for the final setting tank, in which the average orthophosphate concentration was at 2.3 mg/L and the average orthophosphate removal was raised up to 65.10%. Highly dissolved oxygen in the anaerobic lagoon did not release phosphorus effectively. This resulted in an incomplete removal of orthophosphate. However, controlling low dissolved oxygen levels (0.2mg/L) in the anaerobic lagoon could create an environment to facilitate the release of phosphorus and avoid the decrease of anaerobic bacteria. To improve efficiency of orthophosphate removal, this study suggests control of the volume of dissolved oxygen, pH values, biological bacteria, and the ratio of carbon and phosphorus by means of effects of biological regulation. In addition, it is also suggests the temporary solution of the addition of coagulant (PAC). With the provision of enough volume of dissolved oxygen, Ammonia nitrogen (NH3-N) was totally oxidized to Nitrate Nitrogen (NO3-N) and remained at an average concentration of 14mg/L. After July, the concentration of NH3-N increased significantly in the anaerobic lagoon, although the removal rate was still high at 99.20%. This showed that Ammonia nitrogen (NH3-N) removal was affected well by nitrification. Because of excessively high amounts of dissolved oxygen in the aeration basin, NO3-N return in the anoxic basins contained excessively high amounts of dissolved oxygen. In addition, complete removal of nitrogen in the anoxic basin could not be achieved and thus caused an excessively high concentration of total nitrogen in the final settling tank. Six parameters need to be considered in the wastewater treatment for a better removal of Nitrate Nitrogen; the amount of dissolved oxygen, the pH value, temperature, residence time, the carbon- nitrogen ratio, and the biological bacteria classification. Denitrification is the main purpose of having low dissolved oxygen levels (0.5mg/L) in the anoxic basin and how to decrease nitrogen phosphorus pollution that causes eutrophication phenomena in water bodies, then, is a current issue of research. |
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| Advisor Committee | |||
| Files | indicate access worldwide | ||
| Date of Defense | 2018-06-30 | Date of Submission | 2018-07-17 |