Factorial Design Analysis for Turbidity and Humic Acid Removal from High Turbidity Stormwater and Floc Characteristics

階乘設計分析由高濁度颱風原水移除濁度及腐植酸及膠羽特性

G. Annadurai ； 宋尚軒(S. S. Sung) ； 李篤中(D. J. Lee) ； 彭曉峰(X. F. Peng)

《Journal of the Chinese Institute of Chemical Engineers》 33卷4期 (2002/07) Pp. 353-364

https://doi.org/10.6967/JCICE.200207.0353

摘要

本研究以聚氯化鋁(PACl)當作混凝劑處理納莉颱風過後之高濁度原水，針對濁度與有機物的去除效率進行探討。以小角度雷射光散射進行膠羽之粒徑大小與緻密度（碎形維度）量測析；再配合實驗軟體設計方法，針對pH值、濁度、鹼度、PACl劑量、腐植酸含量等參數，探討各種變因之影響。
結果顯示，PACl劑量為濁度去除之主要影響參數；而對殘餘腐植酸濃度而言，pH值則為主要影響參數。當膠羽內部結構較疏鬆時，濁度及殘餘腐植酸均較低；而中量鹼度及PACl加藥量狀態下，疏鬆的膠羽易形成於酸性懸浮液中。腐植酸濃度則需盡可能維持在最低。而產生大膠羽之條件在於中性狀態且高PACl劑量下。若需產生既大且鬆的膠羽則需在操作條件上作一妥協。在高濁度原水中，電性中和機制與濁度和腐植酸之去除間並不具有關聯。

並列摘要

This work investigated the removal efficiencies of the turbidity and organic content from high-turbidity stormwater induced by tropical storm Nari using polyaluminum chloride (PACl) as the coagulant. The resulting floc size and compactness (fractal dimension) were monitored using small-angle light scattering technique. The response surface method along with the Box-Behnken design of experiments was adopted to investigate the effects of pH, turbidity, and alkalinity of the suspension, the PACl dosage, and the dosed amount of humic acid. The PACl dosage was the most significant variable for turbidity removal, while that for humic acid removal was the suspension pH. The flocs corresponding to the removal efficiencies tend to show a loose interior structure for effective removal of both turbidity and humic acid. The acidic suspension with medium PACl dosage and alkalinity level were favorable to producing loose flocs. The results indicated that humic acid concentration should be kept low if possible. The optimal conditions needed to generate large flocs include the neutral condition and a high PACl dosage. A compromise is needed to produce both large and loose flocs. The charge neutralization mechanism does not correspond to turbidity/humic acid removal from high turbidity stormwater.

並列關鍵字

High turbidity ； Humic acid ； PAC ； Floc size ； Fractal dimension