| 摘要: | 台灣地區每逢稍大雨勢，水庫原水中含有大量的泥沙等粒狀物質，使得水庫原水濁度飆高，而影響自來水之原水取得，以致無法供水之窘境。
有鑑於此，本研究主要即探討高濁度水庫原水中，粒狀物質之分離能力，研究傳統淨水處理模式，與尚未被運用於處理淨水的電聚法，於遭遇到高濁度原水時，處理效能及水中粒狀物質之分離能力，以提供將來應用之基礎研究。
經實驗結果證實，高濁度原水中含有相當細小的粒狀物質，其粒徑D(50)為6.5 μm。以傳統的化學混凝分離高濁度原水(500、1,500、3,000 NTU)中粒狀物質，在pH值為7時加藥量為：50、100、150 mg/l，濁度值可處理達3、3.5、3.2 NTU。以電聚法使用鋁為電極，分離高濁度原水中粒狀物質有良好的成效；操作條件為水力停留時間128 sec，電壓150~200V，電流0.4~2.2A，可將高濁度原水(500、1,500、3,000 NTU)處理達3.8、3.8、4.0 NTU；實驗結果並發現，電聚法可以減少高濁度原水中電導度達30 %以上。故可判斷電聚法適合用於處理高濁度原水；然因電聚法尚未被運用於處理高濁度水，技術較不純熟，實有進行模場實驗之必要。另由電聚法與化學混凝處理時間比較，發現兩者之水力停留時間相差15倍以上(128 sec及33 min)，故電聚法具有處理時間短及用地面積小之優勢，以處理高濁度原水。
關鍵詞：電聚、電化學、電能、高濁度、粒狀物、混凝、水處理
Removal of turbidity from raw water is critical to the water treatment plant because of large amount of particles suspended in the water especially after heavy rain showers. It is difficult to remove micrometer sized particles (eg. D(50) = 6.5 μm) due to longer retention is needed for settlement. Our task is to investigate the ability of particle removal from high turbidity reservoir water, and the conventional settlement process, coagulation and electro-aggregation processes were also compared.
The results of the experiments reveal that high turbidity raw water samples (500, 1500, 3000 NTU) can be treated by coagulation at pH 7 at the PAC dosage of 50, 100, 150 mg/l, respectively, and the results come out the treated water of 3, 3.5, 3.2 NTU. The particle removal ability by electro-aggregation process, using aluminum plate as electrodes are significant. The turbidities of water samples (500, 1500, 3000 NTU) decreased to 3.8, 3.8, 4.0 NTU, respectively, under the conditions as followed: 128 second hydraulic retention time; 150~200 V voltage; and 0.4~2.2A electric current. The conductivity of the raw water dropped down at least 30% during electro-aggregation process. The pilot study should be performed in the near future before full scale of application due to insufficient information is available. The time it took for the conventional coagulation is fifteen times longer than that of electro-aggregation. Comparing these two processes, the electro-aggregation may benefit from its smaller size and fast treatment in treating high turbidity reservoir water.
Keyword: electro-aggregation process, electrochemistry, high turbidity, particle removal, coagulation |
