Nagaoka H, Kudo C
Department of Civil Engineering, Musashi Institute of Technology, Tokyo, Japan.
Water Sci Technol. 2002;46(8):119-26.
The performance of the submerged membrane separation activated sludge process with intermittent aeration was investigated in a laboratory scale experiment by changing organic loading rate and intermittent aeration cycle. A rectangular PVC tank was used as an aeration tank, in which a flat-sheet type Micro-Filtration membrane made of poly-olefin with a pore size of 0.2 microm was submerged. Organic loading rate to the reactor was set at 0.3 and 0.8 g-TOC/L/day. C/N ratio in the feed was set at around 5.0 for every condition. Aeration cycle was changed from 10 min-10 min (aeration-stop) to 120 min-120 min in different organic loading conditions. Flux through the membrane was set at 0.25 m/day. Membrane fouling proceeded rapidly in 0.8 g-TOC/L/day conditions. However, when organic loading rate was 0.3 g-TOC/L/day, bacterial metabolic substances were degraded rapidly compared to the production, thereby decreasing viscosity in mixed liquor. Nitrogen removal rate was between 60% and 80% for 0.8 g-TOC/L/day loading, and between 50% and 65% for 0.3 g-TOC/L/day loading. And the nitrogen removal was highest in 40 min to 60 min aeration cycle conditions. Too short aeration cycle did not result in sufficiently long anoxic periods for denitrification while too long a cycle resulted in unnecessary anaerobic periods after depletion of nitrate. Intermittent aeration was effective also for decreasing viscosity in mixed liquor.
通过改变有机负荷率和间歇曝气周期，在实验室规模的实验中研究了间歇曝气的浸没式膜分离活性污泥工艺的性能。使用一个矩形PVC槽作为曝气池，其中浸没了由聚烯烃制成的孔径为0.2微米的平板式微滤膜。反应器的有机负荷率设定为0.3和0.8 g-TOC/L/天。在每种条件下，进料中的C/N比设定为约5.0。在不同的有机负荷条件下，曝气周期从10分钟-10分钟（曝气-停止）变为120分钟-120分钟。通过膜的通量设定为0.25 m/天。在0.8 g-TOC/L/天的条件下，膜污染迅速发展。然而，当有机负荷率为0.3 g-TOC/L/天时，细菌代谢物质的降解速度比产生速度快，从而降低了混合液的粘度。对于0.8 g-TOC/L/天的负荷，氮去除率在60%至80%之间，对于0.3 g-TOC/L/天的负荷，氮去除率在50%至65%之间。并且在40分钟至60分钟的曝气周期条件下，氮去除率最高。曝气周期过短不会导致足够长的缺氧期用于反硝化，而周期过长会在硝酸盐耗尽后导致不必要的厌氧期。间歇曝气对于降低混合液的粘度也有效。
