| 一体式铝盐絮体-超滤膜净水效能与机制 |
| 摘要点击 1448 全文点击 486 投稿时间：2018-06-04 修订日期：2018-08-01 |
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| 中文关键词 一体式膜工艺 铝盐混凝剂 腐殖酸 密云水库原水 膜污染减缓 |
| 英文关键词 integrated membrane process Al-based coagulant humic acid Miyun reservoir water membrane fouling alleviation |
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| 中文摘要 |
| 一体式膜工艺以其占地面积小、污染物去除效率高等优点在水处理工艺中逐渐应用.然而，长期运行后，传统颗粒性吸附剂存在加剧膜表面损伤的风险，同时大多数研究所用吸附剂价格较高，如纳米铁、碳纳米管等.针对上述问题，本文将铝盐混凝剂水解后形成的松散絮体直接注入膜池，基于腐殖酸（HA）和密云水库原水，考察了一体式絮体-超滤膜工艺运行效能及膜污染行为.结果表明，仅HA过膜时，第12 d跨膜压差（transmembrane pressure，TMP）急剧增至76.4 kPa，将膜组件取出经自来水清洗膜表面后TMP降为10.1 kPa（13 d），表明滤饼层是膜污染的主要形式，并且运行期间HA平均去除率仅为23.3%.絮体注入频率、曝气强度及溶液pH能显著影响该工艺运行效能，尤其溶液pH.当采用连续投加方式将43.2 mmol·L-1铝盐絮体注入到pH为6.0、曝气速率为0.3 L·min-1膜池内时，膜污染程度显著降低，第12 d时TMP仅增长到19.5 kPa，清洗之后TMP降为5.6 kPa（13 d），此时HA平均去除率提高至61.2%.此外，密云水库原水实验表明，当原水直接过膜时，TMP也急剧增加，运行12 d时TMP达到38.0 kPa，而清洗膜表面后TMP降低至3.8 kPa（13 d），滤饼层仍然为主要污染方式，同时有机质平均去除率为7.5%.在上述最佳工艺条件下（曝气0.3 L·min-1、溶液pH 6.0）投加43.2 mmol·L-1铝盐絮体时，TMP增长也极其缓慢，12 d时仅增至6.1 kPa，膜表面清洗后TMP降至2.3 kPa（13 d），有机质平均去除率高达58.6%.本研究表明一体式铝盐絮体-超滤膜在水处理中具有潜在的应用价值. |
| 英文摘要 |
| Owing to the small land use and high pollutant removal efficiency, the integrated ultrafiltration (UF) membrane process has been gradually applied in water treatment. However, not only would the membrane surface be damaged by the commonly used granular adsorbents over time, but these types of adsorbents are expensive, such as nano zerovalent iron, carbon nanotubes, etc. To overcome these disadvantages, the loose Al-based flocs were directly injected into the membrane tank in the presence of humic acid and Miyun reservoir water. Results showed that severe membrane fouling was induced by HA alone, and the transmembrane pressure (TMP) significantly increased to 76.4 kPa after 12 d of operation. However, it dramatically decreased to 10.1 kPa after washing with tap water on day 13, indicating that the cake layer was the main fouling mechanism. The average HA removal efficiency was only 23.3% during filtration. In addition, the performance of the integrated flocs-membrane process could be influenced by floc dosage, injection frequency, and solution pH. The integrated membrane performed well with flocs (43.2 mmol·L-1) continuously injected at pH 6.0 (aeration rate at 0.3 L·min-1). The corresponding TMP only increased to 19.5 kPa after running for 12 d, which decreased to 5.6 kPa after washing with tap water on day 13. The average HA removal efficiency increased to 61.2%. Additionally, serious membrane fouling was also induced by Miyun reservoir alone. The TMP increased to 38.0 kPa on day 12, while it decreased to 3.8 kPa after washing with tap water on day 13. The cake layer was also the main fouling mechanism, and the average pollutant removal efficiency was only 7.5%. With floc continuously injected, however, the TMP only increased to 6.1 kPa on day 12. After washing with tap water, the TMP decreased to 2.3 kPa on day 13, and the average pollutant removal efficiency was as high as 58.6%. Based on the excellent membrane performance, the integrated membrane process exhibited potential application in drinking water treatment. |
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