Remove phosphorus from water by submerged macrophyte, Egeria densa Planch

• Main Authors: Pei-Chia Wu, 吳珮佳
• Other Authors: 駱尚廉
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/90608600272277350432

碩士 === 國立臺灣大學 === 環境工程學研究所 === 92 === 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.