碩士 / 大仁科技大學 / 環境管理研究所 / 103 / The extensive use of fossil fuels has caused greenhouse gas emissions increased, thereby affecting global warming and environmental impacts. Therefore, many countries are turning their attentions to develop the new, clean, and renewable energy sources. Microalgae are considered one of the most promising feedstocks for biodiesel production due to the higher growth rates and exceedingly rich in lipid content comparing with other energy crops.
The main objective of the study is to understand the abilities of the mixotrophic microalgae for making biodiesel production and reducing the wastewater pollution. The mixotrophic microalgae were firstly cultured in batch mode to determine the biokinetic coefficients of nitrogen, chemical oxygen demend (COD), and phosphorus on both piggery wastewater and dairy wastewater. Secondly, the effects of aeration ways on cell growth and lipid accumulation of Chodatella sp was studied. For the mixotrophic growth, the effects of nutrients renewal percentage, and biomass harvesting time on the biodiesel production were examined by using a response surface methodology (RSM). Finally, this study further aimed at microalgae harvesting rate by combined preoxidation and coagulation processes t and the activity of regrowth of settled cell.
Experimental results indicated that the microalgae Chodatella sp. cultured in two different wastewaters, the TKN, NH3-N, NO3, NO2, TP and COD removal efficiency reached up ＞90 %, the Chodatella sp. accordingly produced high biomass productivity and lipid productivity under piggery wastewater, 71.57 mg/L．d and 26.37 mg/L．d, respectively. Monod equation was used to obtain the various biokinetic coefficients among the substrates. The NH3-N, COD and TP correlation coefficient (R2) ranged from 0.73 to 0.95, representing highly positive correlation. For comparing the biomass productivity in different aeration ways, under 8 Klux light intensity and 8 % CO2 , the better biomass productivity 105.42 mg/L．d was obtained, while the highest biomass productivity 137.14 mg/L．d was found at the condition of 8 Klux light intensity and aeration rate 2 L/min．L. Considering the economic cost, 1 L/min．L aeration rate is suitable for the growth of this microalgae.
Results from RSM show that the most important factor for lipid productivity is harvesting time under experiments tested. The highest biomass productivity (71 mg/L．d) was obtained at the conditions of nutrients renewal percent (25 %) and harvesting time (3.8 day). For the settling of microalgae by coagulation process, the algae removal rate after peroxidation with potassium permanganate (1 mg/L) followed by alum and ferric coagulation were respective 64.8 % and 35.5 %. However, the lipid content and total fatty acid methyl esters (FAMEs) content of biomass after ferric precipitation existed a better performance, 33.68 % and 3772.9 mg/L, respectively. In addition, the biomass productivity and lipid productivity of regrowth microalgae after peroxidation followed by alum and ferric coagulation reached up to 144.86 mg/L．d, 82.57 mg/L．d and 82.57, 17.11 mg/L．d, respectively. The results indicated that the microalgae regrowth will not be affected by permanganate preoxidation and coagulation, which are beneficial for biomass harvesting.
| Identifer | oai:union.ndltd.org:TW/103TAJ00700033 |
| Date | January 2015 |
| Creators | Hsiang-Lan Huang, 黃湘嵐 |
| 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 | 126 |
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