應用空氣間隙式薄膜蒸餾技術處理各類實廠高電導度廢水之可行性探討

Application of AGMD on Various High Conductivity Wastewater Treatment

袁宜婷(Yi-Ting Yuan)

指導教授 ： 游勝傑 ； 王雅玢

中原大學/工學院/環境工程學系/碩士(2019年)

https://doi.org/10.6840/cycu201900817

摘要

各類產業所產生之廢水若因製程所需而產生具有高鹽份或高電導度，常受限於水回收技術之限制，例如逆滲透與電透析技術有濃度之限制而無法順利進行水回收，因此該製程廢水除非能直接再利用產業否則常須混入其他廢水一起處理或委外處理，因而增加生產成本。本研究利用空氣間隙薄膜蒸餾技術之高鹽阻之特性用以處理各類高電導度廢水，探討直接進行水回收或提濃該類廢水以降低該類處理成本之可行性。
本研究將15種各類實廠廢水進行AGMD三重複試驗，操作條件為進料溫度65°C，Re = 6,923；冷卻溫度20°C，Re = 11,862；設定空氣間隙0.9 mm；操作5小時，可觀察3種不同污染型態之薄膜：5小時試驗之原污染薄膜、自來水清洗之薄膜、10 wt%硫酸與氫氧化鈉及自來水分別清洗之薄膜。結果顯示廢水通量介於5至 13 kg/m2hr 而 電導度具有高度影響通量 R2為0.903，據觀察電導度超過 100,000 μS/cm之水樣，通量低於10 kg/m2h，除了進料成分之外，電導度為主要考量項目之一。本研究最高電導度為PCB業微蝕廢液，電導度為 571,000 μS/cm，通量僅有 6.42 kg/m2hr，然而離子阻擋率高達 99.82 %，本研究結果除了容易揮發之PCB業硝酸銅廢液，其他廢水離子阻擋率均高於 97 %，顯示在高電導度情況下，雖然通量略低仍可以進行操作。進料水樣應避免使用含有高溫下容易解離有機物質之廢水，並且應了解懸浮物特性與提濃析出物質，是否容易黏滯於薄膜表面，如PCB膨鬆劑之膨化物與蝕刻廢液之結晶物。
在高濃度廢水處理上，使用溫差即可操作之薄膜蒸餾技術有望成為零排放技術，在末端進行處理，回收再生水同時可將廢水減量化、濃縮廢水進行迴流操作或回收有價物質等應用，例如結合SLM等回收金屬技術。

關鍵字

薄膜蒸餾 ； 廢水處理 ； 工業廢水 ； 電導度

並列摘要

If the wastewater generated by various industries has the high salt concentration or high electrical conductivity due to the production process, it is often very difficult for the water recycling by the limitation of current technology. For example, the reverse osmosis and electrodialysis have the limitation of treatment concentration and cannot be applied for recycling. Therefore, unless the processing wastewater can be directly reused, it is often necessary to be mixed with the other type of wastewater for further treatment or disposal resulting in the high cost of treatment. In this study, we utilized the air gap membrane distillation technique with the characteristics of high salt resistance to treat various high conductivity wastewater, and explored the feasibility of direct water recycle or wastewater concentrating to reduce the cost.
In this study, 15 types of the factory wastewater were used AGMD for three repeated experiments under the operating conditions of feed temperature 65 ° C, Re = 6,923; cooling temperature 20 ° C, Re = 11,862; set air gap 0.9 mm; operation for 5 hours. Three pollution types of membrane can be observed: the original contaminated membrane under 5 hours operation, washing the membrane with tap water, washing the membrane with 10 wt% sulfuric acid, sodium hydroxide and tap water, respectively. The results show that the membrane flux of wastewater is between 5 and 13 kg/m2hr and the conductivity has the high impact on membrane flux (R2 = 0.903). According to the experimental data, when the conductivity is higher than 100,000 μS/cm, the membrane flux would be less than 10 kg/m2h. In addition to the feed ingredients, the conductivity is one of the crucial parameters to determine the efficiency.
The highest conductivity of 571,000 μS/cm in this study is the micro-etching waste effluent from the PCB industry; the membrane flux is only 6.42 kg/m2hr, but the ion resistance rate is as high as 99.82%. In addition to the volatile cupric nitrate waste effluent of the PCB industry, all the other ion resistance rates could be higher than 97%. Those results indicate that in the case of high conductivity, the membrane still could be operated even in low flux. From the experiments, we found there were some important notices of operation: the feed water sample should avoid the use of wastewater containing easily dissociated organic matter in high-temperature, should understand the characteristics of the suspended solids and the concentrated precipitated substances, and whether it is easy to stick to the surface of the membrane, such as the PCB leavening agent and the crystallization of etching waste effluent.
For the wastewater treatment with high concentration contaminants, the membrane distillation that can be operated with the temperature difference is expected to become a zero-waste technology and be used at the end process to recover wastewater, reduce wastewater, concentrate wastewater for reflux operation or recover valuable substances, such as to combine with SLM or the other metal recycling technologies.

並列關鍵字

Membrane Distillation ； Wastewater treatment ； Industrial wastewater ； Electrical Conductivity

參考文獻

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