Simulating Effect of Dissolved Oxygen on Nitrifying Population in TNCU2 Process－－Application of TWEA1

TNCU2 程序硝化菌族群受溶氧濃度影響之模擬――臺灣活性污泥模式NO.1之應用

In this study, the TaiWan Extension Activated sludge model NO.1 (TWEA1) developed in our laboratory was used to simulate the effect of dissolved oxygen (DO) in aerobic tank on nitrifying population in TNCU2 process. The results indicated that when DO increased from 0.1 to 5 mg L-1, XAOB increased by 4.0 %, XNOB increased by 54.0 %, XPAO increased by 37.6 %, and XH only increased by 5 %. The percentages of XAOB to XTSS increased from 1.23 % to 1.29 %, the percentages of XNOB increased from 0.54 % to 0.84 %, the percentages of XH increased from 69.0 % to 73.2 %, and the percentages of XPAO increased from 8.2 % to 11.3 %. Higher DO was favorable for the growth of XAOB and XNOB which growing obligate-aerobically and owning lower μ values. In the aspect of soluble components, when DO increased from 0.1 to 5 mg L-1, effluent SS concentration maintained at a stable value around 2 mg L-1, SNH4 decreased from 4.3 mg L-1 to 1.8 mg L-1, SNO2 increased from 0.34 mg L-1 to 1.75 mg L-1, SNO3 increased from 0.0 mg L-1 to 2.2 mg L-1, and SPO4 decreased from 1.6 mg L-1 to 0.0 mg L-1. Effluent SS, SNH4, SNO2, SNO3 and SPO4 maintained at stable values of 2 mg L-1, 1.8 mg L-1, 1.75 mg L-1, 2.2 mg L-1, and 0.0 mg L-1, respectively when DO was above 4.0 mg L-1.