地下水觀測井井管腐蝕現況與改善-以臺灣西南地區為例

Corrosion Study of Groundwater Monitoring Well's Pipe-Using Southwest Taiwan as an Example

廖崇淵(Chung-Yuan Liao)

指導教授 ： 陳孝行

國立臺北科技大學/工程學院/環境工程與管理研究所/碩士(2010年)

摘要

經濟部水利署於台灣各地建立地下水觀測井以作地下水調查之用，以利彙集各地下水水文及水質等長期資料，藉以瞭解當地地下水水文地質、水位、水質等資訊，並整合建立完整之資料庫。土壤、水質是造成井管腐蝕與積垢的主要因素，井管腐蝕可分為管內及管外，管內腐蝕和管外腐蝕分別為水質和土壤所造成，而本研究主要是探討管內腐蝕狀況，以水質分析作為化學性評估方法，井體攝影作為物理性評估方法，從水質使井管發生鏽蝕之前因，搭配攝影觀察井管腐蝕情況之後果，從而更加了解井管鏽蝕發生程序及其原因。
於水質部分，將進行腐蝕指標評估，了解其水質之腐蝕潛勢；井體攝影部分，觀察整體井管腐蝕現況，將其腐蝕嚴重性區分為五等級，兩者進行探討其關聯性，但現況「三倍水」採樣方式僅能代表含水層地下水水質狀況，無法代表滯留水造成井管鏽蝕的狀況，因此水質部分搭配觀察分級結果，其相關性會產生不佳之情況，故此種採樣方式無法就井管腐蝕與積垢進行評估。而「三段水」採樣方法是將管內滯留水分為三段後進行採樣分析，才能代表滯留水影響井管腐蝕之情況，建議將現今使用之「三倍水」採樣方法更改為「三段水」採樣方法。於施工前之地下水水質檢測分析結果，作為評估選擇適合之管材，從觀察井管腐蝕現況，已建置之管材發生嚴重鏽蝕，建議以更換UPVC管為優先。地層活動頻繁之區域，將以金屬管材為佳，而焊接接管方式應加強其工法，避免接管處鏽蝕、破裂或管外物質滲入，並增加維護頻率，使觀測井施工維護能夠完善，增加地下水觀測井之使用壽命，減少腐蝕損失維護成本，以利觀測井能夠發揮其效用。

關鍵字

地下水 ； 觀測井 ； 腐蝕 ； 腐蝕潛勢 ； 井體攝影

並列摘要

A borehole-camera-system was used to investigate the corrosion of groundwater well in Southwest Taiwan. Water Resources Agency (WRA) constructed groundwater monitoring wells for observing hydrogeology, water level, water quality and other information of groundwater. The corrosion and scale of wells were related to soil, groundwater and other factors. The corrosion of pipe was caused by water quality and soil. The study used two different analysis methods. One is chemical analysis, and it is based on groundwater quality. The other is physical analysis which observed the pipe status through borehole-camera-system. The result of these two methods can reveal the corrosive situation of well pipe and as a data to improve the groundwater monitoring well pipe.
The water quality of groundwater can be the indicator to know the potential corrosion. This study divided the corrosion status into five levels in order to understand the situation of inside pipe. “Three times the water " sampling method can present the water quality of aquifer, but cannot present the water quality of pipe water. "Three sections of water" sampling method can present the water quality of pipe water which is related with the pipe corrosion.
There are three suggestions from this study as following, so that the groundwater monitoring wells can work effectively:
1. To choose "Three sections of the water" sampling method instead of "Three times the water" sampling method;
2. To use UPVC pipe instead of metal pipe;
3. The welding technology for the pipe should be improved and the frequency of maintenance should be increased.

並列關鍵字

Groundwater ； Monitoring well ； Corrosion

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