Study of Phosphorus Removal from Water Using Algal Turf Scrubber Method

• Main Authors: Chih -Yu Wang, 王之佑
• Other Authors: Wen-Lian Chang
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/80164165822989471789

碩士 === 國立臺灣大學 === 生物環境系統工程學研究所 === 94 === With high adaptability, periphyton could adhere to any surface in the water. Although periphytic microcommunities are subject to various environmental factors, including current, temperature, light intensity, and nutrient, the flora remains thriving at habitat. Artificial wetlands are the commonest ecological engineering for highly polluted wastewater treatment in Taiwan. However, algal turf scrubber method could serve more wildly ranges from livestock industrial one to low contaminated water. Researches have been done on the algae-water treatment experiment with significant results in recent years. Eutrophication in water reservoir has become more and more severe in Taiwan. However, only few artificial wetlands have been built to clean up stream water in the watershed. The purpose of this study was to determine the degree of phosphorus removal by the periphyton incubated in a growth chamber and the proper sites to apply algal turf scrubber method at Jingualiao Creek in Feitsui Reservoir watershed. The laboratory experiment was conducted under semi-enclosed conditions with no further addition of nutrients except initial addition. The onset of initial phosphate concentration ranged from 4 to 136 μg/L, with total phosphorus concentration between 27 and 168 μg/L. After an incubation of 26 days, periphyton community was dominated by filamentous green algae when the initial phosphate concentration was higher than 35 μg/L. The biomass production of periphyton had been as high as 0.05~0.16 g dry weight/m2-day, with ash free dry weight ranging from 0.02~0.11 g/m2-day Under such conditions, phosphate concentration in each culture was reduced to 1~2 μg/L, with total phosphorus concentration lower than 10 μg/L. As a result, the maximum phosphorus removal efficiency has been up to 95.17％. The field research was conducted at Jingualiao Creek in Feitsui Reservoir watershed. After incubated for twelve days, periphyton communities were sampled at 28 sites by artificial substrate and analyzed for biomass and phosphorus content. Water analysis and surveying of habitat physical condition was conducted at the same time. Twenty two environmental variables and bio-index: periphyton phosphorus uptake rate were combined into a data matrix and subjected to the principle component analysis. Six principle components were extracted as salinity factor, nutrient factor, dissolved oxygen factor, turbidity factor, and background factor. With the scatter plot of the first two principle components, the fourth, twentieth, and twenty-third sample site were classified as high nutrient locations. The result suggests that the point source pollution: fourth sample site was the most suitable place to apply algal turf scrubber method because of its high pollution loading. The present study shows that periphyton can remarkably reduce the phosphorus in stream water and thus is able to prevent water reservoirs from eutrophication when it is applied in the watershed.