微孔曝气变速氧化沟循环特性的中试研究

Pilot study on flow characteristics of a variable-velocity oxidation ditch with fine bubble

氧化沟工艺被广泛应用于脱氮除磷系统,其沟宽和流速均相等,这使得缺氧段和微孔曝气段因水流连续性均有相同的不沉降水平流速,造成曝气区流速高,推进能耗大。基于节能理念,为验证氧化沟变速的可行性,对中试变速氧化沟进行实际流速测定,结果表明,变速氧化沟在沟宽0.4 m处,其断面平均流速约为0.15 m/s;在沟宽1.2 m处,其断面平均流速约为0.07 m/s,上述2种沟宽实际流速比值与其对应的理论流速比3∶1相比较小,但该结论验证了氧化沟变速的可行性。另外,对沟内易沉降点不同水深处沉降比和SS分布进行测定,未出现较大的差值,结合长期工艺表面观察未发现泥水分离和泥块上浮现象。

Oxidation ditch process with same ditch width and flow velocities was widely applied to process of nitrogen and phosphorus removal, which caused anoxic and fine bubble aeration sections with the same velocities based on flow balance. However, the same high velocities in bubble aeration section with anoxic section couldn＇ t meet energy-saving. To explore fine bubble oxidation ditch with variable velocities and its feasibility, a novel pilot-scale variable speed oxidation ditch was established and its flow-velocity distribution were measured along the ditch. Result showed that the average velocities of 0.4 m and 1.2 m channel widths were about 0.15 m/ s and 0.07 m/s, respectively being slightly less than the theory ratio 3：1 and variable velocities in oxidation ditch was feasible. It also showed that separating activated sludge with water hand never happened by through measuring sludge settlement ratios and SS at points tending to settle and observing for a long time.