SBR中曝气强度对除磷颗粒的影响

Influence of aeration intensity on phosphorus removal granules in SBR

在3个SBR反应器（R1、R2和R3）中,好氧段分别控制气体流量为0.5、1.0和1.5 L·min-1,研究了不同曝气强度对除磷颗粒的特性、处理性能和生物量等的影响。3个反应器在不同的曝气强度下30 d均实现了除磷污泥颗粒化,而后稳定运行30 d。试验结果表明,曝气强度对除磷颗粒的粒径、形态、含水率、沉淀性、处理效果、生物量等有着重要的影响。颗粒成熟后,R1、R2和R3中颗粒的平均粒径分别为900、1000和1150μm,含水率分别为95.6%、94.2%和93.4%,沉淀速度分别为24~144、29~162和33~178 m·h-1。在40 d后的运行中,R1、R2和R3中COD的平均去除率分别为95%、96%和98%,TP的平均去除率分别为97%、98%和99%。可见,曝气强度较大的反应器中形成的颗粒具有较好的沉淀性、较大的粒径、较低的含水率、较好的处理效果,且形状规则、外表光滑,而较大的生物量及较密实的结构是这些颗粒具有较优性能的主要原因。同时,测定并计算了3个反应器中第51天除磷颗粒的MLVSS/MLSS和生物活性层的厚度,高曝气强度反应器中聚磷颗粒的生物活性层厚度比较大,生物量比较高;并通过计算厌氧阶段P释放量与COD消耗量的比值,证实了本试验除磷颗粒系统中富集了大量的聚磷菌。

Three column sequencing batch reactors（SBR）（R1, R2 and R3） were operated under various aeration intensity of 0.5, 1.0 and 1.5 L·min-1, respectively. The influence of aeration intensity on characteristics, treatment performance and biomass of the phosphorus removal granules（PRGs） were investigated. PRGs were formed in all reactors in 30 days and operated steadily for another 30 days. The results showed that the aeration intensity had an important impact on the settling ability, particle size, morphology, moisture content, treatment performance and biomass. With the increase of aeration intensity, the diameter and settling velocity of matured granules were increased, which were 900 μm and 24—144 m·h-1, 1000 μm and 29—162 m·h-1, and 1150 μm and 33—178 m·h-1 in R1, R2 and R3, respectively, while the moisture contents were decreased and were 95.6%, 94.2% and 93.4%, respectively. Therefore, compared with the low aeration intensity, the PRGs under the higher aeration intensity had better physical characteristics, settling ability and treatment performance due to the more biomass and denser structure. PRGs under higher aeration intensity were spherical or elliptic and had regular contours, but the structure and shape of PRGs under lower aeration intensity was loosened and irregular. Meanwhile, the MLVSS/MLSS, biomass layer thickness of PRGs and P release/COD uptake ratios in all reactors at the 51 th day were calculated. MLVSS/MLSS and biomass layer thickness of granules in R1, R2 and R3 were 78% and 0.34 mm, 82% and 0.35 mm, and 86% and 0.38 mm, respectively. It demonstrated that granules in the reactor with higher aeration intensity had a relatively thicker biomass layer and more biomass. The P release/COD uptake ratios in R1, R2 and R3 were 0.35, 0.35 and 0.36, respectively, indicating that the content of phosphorus accumulating organisms（PAOs） was high in all reactors of this research.