碩士 / 大仁科技大學 / 環境管理研究所 / 102 / Constructed wetland is characterized as low cost, energy conservation, and simply operation. It can not only improve water quality, but also preserve genes of aquatic ecosystem and provide ecological education. One of the most important plant genes in constructed wetland is algae, which can biodegrade the nutrient from aquatic ecosystem and enhances biological decomposition. Algae also produce biomass. However, the algal diversity is affected by several environmental factors, such as temperature, light intensity, nutrient content, and toxic chemicals.
The objectives of this study are to investigate the seasonal variations in algal species and its relationships associated with environmental factors in the Kaoping river and Linluo constructed wetland by using multivariate analysis. Four seasonal sampling at various ponds within constructed wetlands from October 2011 to May 2012 were collected and analyzed for algal species and water quality according to EPA’s NIEA protocols. Furthermore, a potential algal strain, Chlorella sp., isolated from the wetland was used as a target strain to examine the correlations among the factors (temperature, time, and aeration rate) that affect the biomass production and nutrient removal rate. A central composite design (CCD) method was used thereby to understand the function of algae in wetland.
Results indicate, in multivariate analysis, that the major dominant algal species in Kaoping river constructed wetland were Nitzschia palea, Chlorella sp., Euglena sp. and Oscillatoria sp. And the water temperature was significantly correlated with Nitzschia palea accompanied a Pearson correlations coefficient of -0.505 at a 99% confidence level (p < 0.01) while a significant correlation with a coefficient of 0.557 between sunlight intensity and Euglena sp. was observed. For Linluo constructed wetland, Cyclotella meneghiniana, Scenedesmus sp., Phacus sp., and Aphanocapsa elachista were the major dominant species. Moreover, the relationship between Cyclotella meneghiniana and sunlight intensity (-0.678, p < 0.01) was more correlated than that of water temperature and nitrate concentration (0.495, p < 0.05).
Results from the CCD tests showed that under the experimental conditions considered the growth rate and lipid productivity significantly dependent on aeration rate and time. The most import factor for lipid productivity is aeration rate, while time significantly effected nutrient removal from piggery wastewater by Chlorella sp. High lipid production and nutrient removal rate were obtained at the conditions, which maintained temperature (25 ºC), aeration (1.2 air L/min.L), and incubation time (7 day). All cultures in CCD tests led to similar fatty acid compositions, comprising palmitic (C16:0), heptadecanoic (C17:1), oleic (C18:1), linoleic (C18:2), and linolenic (18:3) acids. Chlorella sp. is suitable as a biodiesel feedstock. It is not only produced biomass, but also could assimilate up to 86.4 % total nitrogen, 99.2 % total phosphorus, and 72.5 % COD from piggery wastewater, respectively. Microalgae in wetland biodegrade nutrient from wastewater and produce biomass. It is a promising process for pollution degradation and biodiesl production if wetland has a suitable residence time and available aeration.
| Identifer | oai:union.ndltd.org:TW/102TAJ00700002 |
| Date | January 2014 |
| Creators | WEI-HAN LEE, 李威翰 |
| Contributors | Jen-Jeng Chen, 陳振正 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 172 |
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