Control of Disinfection By-Products Formation in Feng-Shan Reservoir by Ozonation Combining with the Traditional Drinking Water Treatment Processes
| Autor: | Peng-Yu Liu, 劉彭譽 |
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| Rok vydání: | 2002 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 90 Due to the presence of higher concentration of ammonia nitrogen and organics in the raw water of Feng-shan reservoir located in southern Taiwan, traditional process of drinking water treatment is unable to serve a satisfactory result on procuring potable finished water for public uses. Since chlorine is often overdosed in the raw water and disinfection facility, the formation of chlorinated disinfection by-products have substantially limited the water from potable purpose. This research was divided into two phases. The first phase was focused on the long-term operation of a pilot-scale plant fabricated with conventional treatment units plus ozoantion and BAC processes to degrade organic substances and to control the formation of DBPs. The second phase was primarily aimed on the fundamental analysis on the characteristic of organic components and the effects of ozonation on those organics separated by XAD-8 resin into hydrophobic and hydrophilic forms. Results in the pilot-scale performance have demonstrated to achieve a significant removal on turbidity and ammonia nitrogen from the raw water. The reduction of ammonia nitrogen is attributed to the function and mechanism of nitrificaiton in the sand filter and GAC bed, where the nitrobacter is thought to predominantly proliferate. Although the organic precursors of DBPs, including NPDOC and A-254, shows an apparent reduction by both GAC process alone and ozonation plus BAC, the post-ozonation seems not to provide additional enhancement in degrading organic contents. In the second phase, lower molecular weight organics (MWCO < 1000 Da) are found to be the main part of organic matters in the raw water. In addition, these low molecular organics also contribute more formation potential of THM and HAA. The ratio of hydrophilic and hydrophobic organics in the raw water is approximately 64 to 36, indicating that hydrophilic ones take remarkable advantage in the organic composition. Ozonation can lead to an obvious shift for the organic molecules from higher molecular weights into lower ones. Furthermore, the increase in THMFP after ozonation shows the intermediate products formed has higher formation potential of chlorinated by-product than their original organics. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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