Study on Operational Characterization of Anoxic-Oxic Biological Nitrogen Removal Process

• Main Authors: Wen-hsien Tsai, 蔡文賢
• Other Authors: YU-JAN CHOU
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/49912609209207874467

碩士 === 輔英科技大學 === 環境工程與科學系碩士班 === 94 === Lots of high mountains and short rivers are the specific characteristics in Taiwan geographical environment, and it is difficult to find more water resources. With tap-water consumption increasing recently, recovering treated wastewater form domestic wastewater treatment plant to be irrigation water has been a trend in the field of nature resource conservation in developed countries. This research cultivated activated sludge in anoxic-oxic(AO) biological nitrogen removal process by using synthetic wastewater(CODt=300mg/L, TKN=40mg/L, T-P=5mg/L). Hydraulic retention time(HRT), external sludge recycle ratio(r) and operational temperature were controlled at 10hrs, 0.25 and 25 centigrade, respectively. Residual effluent nutrients concentrations resulting from different sludge retention time(SRT=15、30dyas) and nitrifying liquor recycle ratio(R=0.0、1.5、2.5) were investigated under steady-state. The sludge samples taken from oxic zone in AO process were selected to identify biological diversity by means of molecular biology experiments. Furthermore, monitoring instruments were installed to measure biological parameters, including dissolved oxygen(DO), oxidation/reduction potential(ORP) and pHs, in reactive zones during experimental period. Experiment results demonstrated average mixed liquor suspended solid (MLSS) concentration in reaction zone increased when SRT increased. Longer SRT resulted in the decreasing activity of sludge. Total nitrogen (T-N) removal efficiency in SRT=15days was better than that in SRT=30days. Besides SRT=30days(R=0.0), residual T-N concentration in effluent were under 10mg/L in this research. Furthermore, residual T-N concentration were less than 4mg/L in the run that controlled SRT=15days(R=1.5, 2.5). The biological diversity of activated sludge were to be nitrifying, denitrifying, utilization of phosphate, CODt decomposition and filamentous microorganisms in SRT=30 days(R=0.0, 2.5) and 15 days(R=0.0, 2.5) in this research.