沉水植物對於水中磷的去除之研究－以水蘊草為例

Remove phosphorus from water by submerged macrophyte, Egeria densa Planch

吳珮佳(Pei-Chia Wu)

指導教授 ： 駱尚廉

國立臺灣大學/工學院/環境工程學研究所/碩士(2004年)

https://doi.org/10.6342/NTU.2004.00928

摘要

在不考量微生物作用和土壤吸附的前提下，以實驗室規模來探討沈水性水生植物—「水蘊草」去除水中磷濃度的效果，嘗試來定位沈水性植物在濕地中的角色，並希冀能對日後人工濕地設計或一般水域施工設計上提供參考。
水蘊草(Egeria densa Planch)為一種多年生沈水植物，已在台灣歸化多年，在各地的溝渠中皆可見到大量族群，尤以宜蘭等北部縣市為多。常生長於溝渠、池塘、稻田等環境。
實驗結果顯示：含有水蘊草的水體在水力停留時間為9天，平均溫度為29.4℃下，初始磷濃度為0.36mM人工水樣，其正磷酸鹽去除率為27.1﹪，其總磷去除率為26.9﹪；在初始磷濃度為0.27mM人工水樣，其正磷酸鹽去除率為39.8﹪，其總磷去除率為33.3﹪。
無論是測得的溶氧或是飽和溶氧率，對照無水蘊草的水體，皆是含有水蘊草的水體較高，溶氧甚至超過當時水中飽和溶氧。
而在類似的起始環境下，無論是總磷或正磷酸鹽，監測期間平均溫度較低者（約25℃），其去除效率較佳，而平均溫度較高者（約30℃），其去除率較低，甚至不及25℃時的去除率之一半。
另外，pH值也是影響磷利用的因子之一。水蘊草隨著pH值日漸上升，會減緩吸收正磷酸鹽的能力。

關鍵字

水蘊草 ； 沈水植物 ； 人工濕地 ； 磷

並列摘要

A lab-scale experiment, ignoring microbial effect and soil adsorption, was investigated to remove phosphorus from water by submerged macrophyte, Egeria densa Planch, in order to realize the position of submerged macrophyte in wetlands, and provide some suggestions for subsequent wetland design or plant application in littoral construction.
Egeria densa Planch is a kind of perennial plant. It has been naturalized in Taiwan for many years, so it can easily be found around ditches, especially in north districts like Ilan County. Egeria densa Planch often grows in ditches, ponds, and rice paddies.
When HRT (hydraulic retention time) is 9 days, mean temperature is 29.4℃, and initial concentration of phosphorus is 0.36mM, the experimental results of the percent of orthophosphate and TP removed are 27.1﹪and 26.9﹪, respectively. In the same condition but initial concentration of phosphorus being 0.27mM, the experimental results of the percent of orthophosphate and TP removed are 39.8﹪and 33.3﹪, respectively.
In the aquatic system with Egeria densa Planch, dissolved oxygen (DO) and dissolved oxygen saturation were higher than those of aquatic system without Egeria densa Planch. Further, DO of the aquatic system with Egeria densa Planch was so high that it could exceed saturated DO at that temperature.
In the similarly initial condition, orthophosphate and TP were both removed better at lower mean temperature (≒25℃) than higher mean temperature (≒30℃). Further, at higher mean temperature (≒30℃), the removal effect of orthophosphate and TP was less than a half of that at lower mean temperature (≒25℃).
In addition, pH is one of the factors that can affect phosphorus to be used by Egeria densa Planch. The more pH increases, the more ability of Egeria densa Planch to uptake phosphorus will decrease.

並列關鍵字

constructed wetland ； phosphor ； Egeria densa Planch

參考文獻

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