| Summary: | 碩士 === 淡江大學 === 水資源及環境工程學系碩士班 === 101 === The nitrogen and phosphorus in aquaculture wastewater are difficult and expensive to be removed by traditional wastewater treatment process. Therefore aquaculture industry usually dilutes its wastewater by groundwater or direct outfall to natural water body that cause subsidence in coastal area or algal blooms. This study tries to test the feasibility of using microalgae, namely the Tetraselmis sp., to treat aquaculture wastewater and find the optimal conditions for the Tetraselmis sp. growth and the removal of nitrogen and phosphorus.
The study concludes that Tetraselmis sp. growth in a 12,000 Lux light intensity and 12 hours light/dark period in a bio-photo reactor is better than that cultured under sun light and a 24 ± 1oC is best temperature setting for microalgae grow. An initial N/P ratio of 3/1 provides the best Tetraselmis sp. growth and nutrient removal. When artificial culture was used in growing microalgae, the cultured environment usually encounters limited carbon source and microalgae deposition problems. Aeration was applied to prevent microalgae settlement, to increase microalgae growth and to shorten nitrate removal time. A stirring only without aeration did not improve both microalgae growth and nitrate removal. Compared with nitrate removal, phosphate is always removed faster in all tested cases by Tetraselmis sp.. This study concludes that using Tetraselmis sp. in removing nitrate and phosphate in aquaculture wastewater with appropriate operations is feasible.
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