摘要
假定颗粒污泥为球状,通过实验确定动力学参数,建立氧传质模型并进行了验证。结果表明,利用失活颗粒污泥DO变化,得出颗粒污泥氧扩散系数为0.45×10-9m2.s-1;利用烧杯实验,得出了氧比消耗速率0.10 g O2.(g MLSS)-1.h-1,氧半饱和常数为0.65 mg.L-1。模型求解发现,表面DO越大,DO梯度越大,颗粒污泥表面径向传质能力越强,氧穿透颗粒污泥的距离越远,但是粒径很大时(如半径1.5 mm),虽然表面DO为4.0 mg.L-1,但依然没有穿透颗粒污泥,当r/R为0.49～0.65之间时,DO梯度迅速为0;在颗粒污泥半径很小(<0.5 mm)时,氧完全能穿透整个粒径,同时梯尔模数足够小,内扩散有效因子接近1不变,氧扩散可忽略不计;对于相同的梯尔模数,表面DO高时,内扩散有效因子越大,说明氧扩散的动力越强、受限制的程度越小。
Oxygen transfer is limited in aerobic granules by compact microbial spatial structure. Aerobic granules were supposed to be spherical, and kinetic parameters were calculated through tests. A simplified equation of mass balance for steady-state diffusion of oxygen was set up and verified. Effective diffusivity was 0.45 × 10^-9 m^2· s^-1 , through dissolved oxygen （DO） change of deactivated granular sludge. Oxygen specific consumption rate and oxygen half saturation coefficient were 0. 10 g O2 · （g MLSS）^-1 · h^-1 and 0.65 mg· L^-1 through beaker test under the condition of COD 400 mg · L^-1 and NH4-N 100 mg · L^-1. The higher the oxygen concentration and concentration gradient, the stronger and the further oxygen could penetrate. When the radius of granular sludge was more than 1.5 mm, oxygen could not penetrate, despite oxygen concentration was 4.0 mg· L^-1. When r/R was between 0.49 and 0.65, the concentration gradient became zero. When the radius was very small （less than 0.5 mm）, oxygen could fully penetrate into granules. At the same time, Thiele modulus was very small and effectiveness factor was near to 1, oxygen diffusion limitation could be neglected. Effectiveness factor was larger with the increase of oxygen concentration, which made oxygen limitation less.
出处
《化工学报》
EI
CAS
CSCD
北大核心
2009年第6期1540-1545,共6页
CIESC Journal
关键词
好氧颗粒污泥
氧传递
梯尔模数
内扩散有效因子
aerobic granular sludge
oxygen transfer
Thiele modulus
effectiveness factor
