Investigation of N2O emission and control strategy for Dihua wastewater treatment plant

• Main Authors: Wei-Chun Chien, 簡偉駿
• Other Authors: Sheng-Jie You
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/05307296049691631352

碩士 === 中原大學 === 生物環境工程研究所 === 101 === Biological wastewater treatment plants (WWTPs) release significant concentrations of N2O to the atmosphere. This study aims to address this problem in Taiwan by focusing on the N2O emissions of Dihua WWTP in Taiwan, and it was divided into three main parts: (a) the establishment of a standard sampling method and N2O emission factor through the short-term continuous monitoring of N2O concentration from the WWTP, (b) the establishment of emission factor through the long-term continuous monitoring; and (c) the Investigation of N2O control strategy to minimize N2O emission. It was found that the average concentration of N2O-N emissions from short-term continuous monitoring was 209.3 ppmv and long-term continuous monitoring was 295.4 ppmv. The changes of C/N ratio at the 2nd oxic tank is from 2 to 6, from the 5th oxic tnak that it is from 10 to 20. For the 2nd anoxic tank the value is lower than 10, and for the 3rd secondary clarifier, the increase in reflux and decrease in water level are the means for controlling the N2O emission in Dihua WWTP. The emission factor was found to be 0.02 ± 0.01 kg N2O/kg N. Using this value, the equivalent carbon dioxide emission of Taiwan’s sewage system was estimated as 388.8(KtCO2 eq) (at 10% utilization of advanced wastewater treatment process) to 28.9(KtCO2 eq) (at 100% utilization of advanced wastewater treatment process). The results showed improved utilization of advanced sewage treatment process, not only can improve the water quality but also to lower N2O emissions. Results of this study will help develop emission factors, estimate N2O annual emissions and also lower N2O emission levels.