研究报告
李永林,范文雯,袁林江,罗大成,刘传波.气升流速变化对SBR污泥颗粒化的作用及机理[J].环境科学学报,2017,37(10):3642-3648
气升流速变化对SBR污泥颗粒化的作用及机理
- Effect and mechanism of variation of superficial gas upflow velocity on sludge granulation in SBRs
- 基金项目：国家自然科学基金（No.51278406）
- 作者
- 单位
- 李永林
- 西安建筑科技大学, 西北水资源与环境生态教育部重点实验室, 陕西省环境工程重点实验室, 西安 710055
- 范文雯
- 西安建筑科技大学, 西北水资源与环境生态教育部重点实验室, 陕西省环境工程重点实验室, 西安 710055
- 袁林江
- 西安建筑科技大学, 西北水资源与环境生态教育部重点实验室, 陕西省环境工程重点实验室, 西安 710055
- 罗大成
- 西安建筑科技大学, 西北水资源与环境生态教育部重点实验室, 陕西省环境工程重点实验室, 西安 710055
- 刘传波
- 西安建筑科技大学, 西北水资源与环境生态教育部重点实验室, 陕西省环境工程重点实验室, 西安 710055
- 摘要：采用两个相同的SBR反应器：R1保持恒定气升流速3.0 cm·s-1，R2气升流速由3.0 cm·s-1逐渐降低至1.0 cm·s-1，对比研究了气升流速变化对絮体污泥凝聚和颗粒化的作用.结果表明：R1中35 d后絮体污泥全部转变成均值粒径为564.59 μm的颗粒污泥；R2中24 d后絮体污泥全部转变成均值粒径978.71 μm的颗粒污泥.R2气升流速由3.0 cm·s-1逐渐降至2.0 cm·s-1时，污泥的分形维数（D2）增大；气升流速由2.0 cm·s-1逐渐降到1.6 cm·s-1时，D2先下降后上升，污泥粒径比增长率为0.16±0.01，微生物颗粒表面所受的剪切解吸附率随粒径的增长由调整前的1.35×10-2 mg·cm-2·d-1（以VSS计，下同）略微降低后升高至1.88×10-2 mg·cm-2·d-1，颗粒结构变得更加致密；气升流速小于1.6 cm·s-1之后，旋涡尺度作用减弱，D2持续减小.总体上，当气升流速递减后，R2中污泥混合液流变特性发生了变化，形成的漩涡尺度大于R1，促使更多体积分数的污泥分布在漩涡尺度的耗散范围内，加剧耗散对应范围粒径大小的污泥剪切凝聚，加快了污泥颗粒化进程.
- Abstract：Two identical sequencing batch reactors R1 and R2 were adopted to study the effects of variation of the superficial gas upflow velocity on coagulation of floc and sludge granulation. The superficial gas upflow velocity was kept constant at 3.0 cm·s-1 in R1 while gradually decreased from 3.0 cm·s-1 to 1.0 cm·s-1 in R2. The results showed that granular sludge cultivated successfully after 35 d operation in R1 with the mean diameter of 564.59 micrometer, while it took merely 24 d in R2 to obtain the granular sludge with the mean diameter of 978.71 micrometer. While the superficial gas upflow velocity decreased gradually from 3.0 cm·s-1 to 2.0 cm·s-1 in R2, fractal dimension (D2) of the sludge increased continuously. As the superficial gas upflow velocity decreased from 2.0 cm·s-1 to 1.6 cm·s-1, the D2 decreased firstly and then increased subsequently. The specific expanding ratio of diameter of the sludge was calculated as about 0.16±0.01. The biomass-shear-loss rate of the sludge varied from 1.35×10-2 mg·cm-2·d-1 before adjustment, then declined slightly, and finally increased to 1.88×10-2 mg·cm-2·d-1 which affected by the increase of sludge size. Meanwhile, the particles structure of the sludge became more compact. When the superficial gas velocity was kept less than 1.6 cm·s-1, the force of eddy became weak and D2 decreased. In general, the rheological properties of the mixed liquor in the reactors changed as the superficial gas upflow velocity reduced. In R2, the eddy scale was greater than that in R1. More fraction of the sludge was distributed in dissipation range of the eddy scale in R2, and the sludge granulation was faster via enhancing shear cohesion of the floc in the corresponding dissipative region.
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