傳統淨水處理程序對水中壬基酚類化合物去除效果之研究

Abstract

壬基酚類化合物在自然水體中普遍存在而容易偵測到其存在，因此在飲用水中的量測與去除漸漸受到重視。本研究之研究目的在於找出適當的方法偵測水中低濃度的壬基酚（NP）、辛基酚（OP）、壬基酚單乙氧基醇（NP1EO）、壬基酚二乙氧基醇（NP2EO）以及壬基酚單羧酸（NP1EC），並在實驗室中建立一套模擬淨水處理程序來評估這些壬基酚類化合物在飲用水處理流程中的移除效用。另外，本研究亦於一個包含慢沙濾單元的離島自來水廠進行這些壬基酚類化合物的移除效用的研究調查。本研究使用自動固相萃取搭配極致液相層析/串聯式質譜儀來偵測水體樣本中的壬基酚類化合物。這些壬基酚類化合物的偵測極限在0.99到13.06 ng/L之間。 在模擬淨水處理程序的部分，研究顯示加氯處理對於控制添加到水樣中的壬基酚和壬基酚二乙氧基醇是很重要的方法。一旦加氯劑量滿足水樣的需氯量，加氯處理對於移除壬基酚和壬基酚二乙氧基醇之效率可以達到60-90%。但是研究亦顯示混凝、沉澱和過濾的步驟並不能有效地移除壬基酚和壬基酚二乙氧基醇。這些處理程序反而是對壬基酚單羧酸有不錯的移除效果。在實廠的研究中發現，除了加氯處理之外，壬基酚和壬基酚單羧酸在經過慢沙濾流程後有很好的移除效果，這顯示生物降解處理是一個適合控制其化合物的方法。然而在水廠中若使用塑膠管線，則很容易會再次於水樣中測得壬基酚之存在，因此以目前的淨水處理流程來說，即使在清水中測得的壬基酚濃度很低，其存在似乎是無可避免的。

The detection and removal of nonylphenolic compounds from drinking water have gained attention since these group of compounds have been widely detected easily in natural waters. The purposes of this study were to find a suitable method for detection of nonylphenol (NP), octylphenol (OP), nonylphenol monoethoxylate (NP1EO), nonylphenol diethoxylate (NP2EO) and nonylphenol monocarboxylate (NP1EC) in water samples with low levels at the same time; to set up a simulated water treatment processes in the laboratory to evaluate the removal of these nonylphenolic compounds; and to investigate the treatment efficiency for these nonylphenolic compounds in a full scale water treatment plant of an offshore island of Taiwan. This study used automated solid phase extraction and ultra-performance liquid chromatography, equipted with tandem mass spectrometry (UPLC-MS/MS) for detection of low levels of these compounds in water. The results showed that the limits of detection for these compounds were ranged from 1.0 to 13.6 ng/L. In the studies of simulated water treatment processes, chlorination played an important role for the control of NP and NP2EO spiked in the waters. The treatment efficiency could be 60-90% for the removal of NP and NP2EO with sufficient chlorine dosages that have satisfied the chlorine demand. However, coagulation and rapid filtration processes were not so effective for the reduction of NP and NP2EO in water. However, it has been found that alum coagulation was effective for removal of NP1EC. On the other hand, NP and NP1EC had a considerably good degree of removal after slow sand filtration in the water treatment plant investigated, and the results showed that control of those compounds through biodegradation was a suitable alternative. In addition, it was very easy to detect the existence of NP when the plastic tubes and pipes were used. Hence, the occurrence of NP in treated water was unavoidable now even though its concentration was quite low.