- 學位論文
流體化床磷酸鈣結晶回收污水處理廠磷之研究
The Study of Phosphorus Recovery from WWTP by Fluid-Bed Crystallization of Calcium Phosphate
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摘要
本研究以流體化床磷酸鈣結晶技術，回收處理公共污水廠之含磷濃縮液為目的，首先於實驗室進行評估試驗，利用人工配製合成污水，進行磷酸鈣介穩區試驗，之後以水力停留時間、pH值、Ca/P莫耳比等變因，找出磷酸鈣最佳操作條件，並依試驗結果作為模型廠試驗之操作參考，進行模型廠磷酸鈣結晶評估試驗。 HAP實驗室評估試驗結果顯示，當PO43--P濃度為50 mg/L時，pH值於8.0-8.5，可使流體化床達介穩定區。磷酸鈣合成污水試驗，以pH值8.6、Ca/P莫耳比1.75為最佳操作條件，其結晶效率約為55-60%，去除率約為60%，而脫水濾液於此條件下，亦有相同結晶成效，且去除效率更佳。模型廠操作結果顯示當濃度於25-30 mg/L，pH為 9.0操作下，平均結晶率為52.0%。PO43--P濃度調整至100 mg/L時，平均結晶率及去除率為75.0%及83.7%。當初始PO43--P濃度較高時，結晶反應較不易受水體中雜質所干擾，以PO43--P 25 mg/L及100 mg/L比較，其結晶產物晶XRD分析後，以PO43--P 100 mg/L結晶物之晶型較為明顯。另外，試驗產出之結晶珠含水率為6-10%，經XRD分析為Ca5(PO4)3(OH)及CaHPO4‧2H2O型態之複合磷酸鈣產物。ICP分析結果僅測出微量Cr、Cu、Zn金屬。
並列摘要
This objective of this study is to recovery phosphorus concentrate from the public sewage treatment plant. First, use of artificial synthetic wastewater for calcium phosphate metastable zone defined in laboratory trials to assessment. Based on the results of metastable zone study, calcium phosphate crystallization was tarried in the laboratory, to identify optimal conditions of calcium phosphate crystallization, include hydraulic retention time, pH and Ca/P molar ratio. The pilot test for calcium phosphate crystallization evaluate is accordance with laboratory trials results. Calcium phosphate crystals in the laboratory trials showed that, the PO43--P concentration of 50 mg / L, the pH value of 8.6, Ca / P molar ratio of 1.75 was the best operational conditions, The crystal and removal efficiencies were about 55-60% and 60% respectively. The dewatering filtrate in this condition has the same efficiency. The pilot test for calcium phosphate crystallization showed that, the PO43--P concentration of 25-30 mg/L and, pH 9.0, the average crystal ratio was 52.0%. when the PO43--P concentration increased to 100 mg / L, the average ratio of crystallization and removal were 75.0 and 83.7% respectively. Comparative of PO43-- P 25 and 100 mg/L of the crystalline product base on XRD analysis, the crystals of PO43--P 100 mg/L showed more obvious polymorph. Moreover, the moisture content of crystal pellet was of 6-10%, and the crystal morphology were Ca5(PO4)3(OH) and CaHPO4‧2H2O of compelx calcium phosphate product. ICP analysis shows that only slight Cr、Cu and Zn metal in the crystal pellet.
參考文獻
1. Joko, I., “Phosphorus removal from wastewater by the crystallization method“ , Wat. Sci. Tech. 17, 121-132, (1984).
2. Ping Zhoua et al., “Heavy metal removal from wastewater in fluidized bed reactor”, Water Research 33, 1918-1924, (1990).
3. M.M. Seckler et al., “Calcium phosphate precipitation in a fluidized bed in relation to process conditions: A black box approach”, Water Research 30, 1677-1685, (1996).
4. Pao-Chi Chen et al., “Morphology and growth rate of calcium carbonate crystals in a gas-liquid-solid reactive crystallizer”, Chemical Engineering Science 52, 4174-4177, (1997).
5. P. Battistoni et al., “Phosphate removal in anaerobic liquors by struvite crystallization without addition of chemicals: Preliminary results”, Water Research 31, 2925-2929, (1997).