碩士 / 嘉南藥理科技大學 / 環境工程與科學系 / 100 / Due to the lack of surface water resources, desalination of seawater has been carried out in order to supply fresh water in the Penghu island region. In general, the Penghu Seawater Desalination plant uses reverse osmosis (RO) equipped with membrane cleaning. The effect of membrane material, duration of cleaning time and type of chemical reagents on the membrane cleaning efficiency has been investigated. The study also determined the effect in the application of MF and UF on the efficiency of membrane operation. At each run, samples of the membrane scale was obtained and analyzed in order to effectively understand the contributing factors that cause membrane fouling.
In the desalination process, NaOCl is the recommended chemical agent to be used in cleaning HPI PTFE membranes. During a severe flux reduction, HCl is utilized as a supplementary chemical agent in membrane cleaning. However, HCl as chemical agent is not recommended in cleaning HPO PTFE membranes. It is observed that increasing dosage of NaOCl does not have a significant effect in improving the membrane cleaning efficiency. In this study, the flux recovery rate for HPO PTFE membranes was poor due to irreversible pore blocking caused by marine bacterial cells with size range of 0.2~0.8 µm.
In utilizing UF as a pretreatment procedure, better flux recovery rates were attained where lower dosages of NaOCl was used and smaller flux reduction was observed. During membrane cleaning using HCl, the membrane scales obtained were composed of inorganic elements of acidic nature. The residual inorganic elements are effectively washed from the membrane surface using NaOH combined with NaOCl while organic pollutants are effectively removed from the membrane surface using NaOCl alone. It is observed that NaOCl is more suitable and more effective in cleaning UF membranes.
| Identifer | oai:union.ndltd.org:TW/100CNUP5515017 |
| Date | January 2012 |
| Creators | Chien - Jung, 林建榮 |
| Contributors | Chi-Chuan Kan, 甘其銓 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 97 |
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