以反應曲面法探討配水管線之防蝕水質組合

Investigation of the effect of water quality composition on corrosivity of drinking water using response surface methodology（RSM）

陳妤亭(Yu-Ting Chen)

指導教授 ： 李奇旺

淡江大學/工學院/水資源及環境工程學系碩士班/碩士(2011年)

https://doi.org/10.6846/TKU.2011.00406

摘要

過去文獻及研究幾乎沒有針對多個配水管線之腐蝕因子一起進行實驗，都只以一次變動一個因子方式進行實驗並探討，此傳統方法未必能找尋最佳化組合，因腐蝕因子間皆會相互影響，故本實驗將腐蝕之因子進行部分因子設計實驗，篩選出對於腐蝕速率及總鐵濃度較為顯著之因子進行反應曲面法，再以聯立最佳化技術尋求符合飲用水質標準的最佳解。
本研究以配水管線使用的鑄鐵材質試片進行瓶杯試驗，實驗參數為pH（6.0-8.5）、鹼度（50-150 mg/L as CaCO3）、餘氯濃度（0.2-1.0 mg/L）、磷酸鹽防蝕劑（0-1 mg/L as P）、實驗時間（2-10天）、水溫（6-38℃）和水體搖晃（0-140 rpm）。實驗參數範圍是參照文獻及目前的飲用水質標準選定。
由部分因子設計可知，對於腐蝕速率較為顯著之主效應為溫度、搖晃、鹼度；而對總鐵濃度較為重要之前三個顯著主效應為pH、實驗天數、溫度。最後篩選出pH值、鹼度及水溫三個參數進行反應曲面法，結果發現在水溫6℃、pH 8.5及鹼度為50-130 mg/L可達到較好的防蝕水質組合，可減少飲用水產生色度及增加管線的使用年限。

關鍵字

反應曲面法 ； 部分因子設計 ； 鑄鐵 ； 配水系統 ； 藍氏飽和指標

並列摘要

Face-centered central composite design (FCD) model, a model that belongs to the response surface methodology (RSM), was used in this study to obtain the optimum operating conditions for less corrosion rate and less release of iron in the solution. Then, the best operation condition is found out through simultaneous optimization technique.
In the research, the ductile-iron of coupon is used for the bench-scale test, and the factors tested are pH (6.0-8.5), alkalinity (50-150 mg/L as CaCO3), chlorine (0.2-1.0 mg/L), phosphate inhibition (0-1 mg/L as P), contact time (2-10 days), temperature (6-38℃) and rotation (0-140 rpm). The selected range of the factors mentioned above is based on the literatures and the present drinking water standards of Taiwan.
According to fractional factorial design, the most significant factors affecting corrosion rate are temperature, rotation and alkalinity. On the other hand, pH, contact time and temperature are the main factors affecting the release of iron in the solution. Finally, pH, alkalinity and temperature are selected to build the corrosion models using response surface methodology. Based on the models, the combination of operation condition with less corrosivity in terms of weight loss of test coupon and release of iron in solution is at temperature of 6℃, pH of 8.5 and alkalinity of 50-130 mg/L.

並列關鍵字

Response surface methodology (RSM) ； Fractional factorial design ； Ductile-iron ； Water distribution system ； Langelier saturation index

參考文獻

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