單槽式生物程序進行碳氮去除之研究

Abstract

Biological nitrification - denitrification process is widely used to remove nitrogen from wastewater. However, multiple stages are required because nitrification and denitrification need opposite reaction conditions. In this study, modified entrapped mixed microbial cell (EMMC) process was investigated for simultaneously removal of carbon and nitrogen in one reactor. Sphere - shaped sludge carrier, where aerobic and anoxic conditions coexist, were used. For small (d = 2.5 cm) carrier, nitrification efficiency of 100% and total nitrogen removal of 93% were achieved at aeration mode of 1:2 (on:off) (hr), hydraulic retention time(HRT) of 12 hr and C/N ratio of 6.8. For large (d = 5 cm) carrier operated under the same condition, nitrification efficiency and total nitrogen removal efficiency were 96.7% and 83.7%, respectively. It was found that small carrier had better performance of nitrification efficiency and total nitrogen removal efficiency than large carrier in most operation condition. The differences between them, however, weren’t very distinct. COD removal efficiency was maintained above 91.8%, and it wasn’t strongly affected by different operation conditions. Modified EMMC process could remove nitrogen from wastewater under adequate operation condition without decreasing COD removal efficiency.