Modification of UASB reactor by using CFD simulations for enhanced treatment of municipal sewage.
Modification of UASB reactor by using CFD simulations for enhanced treatment of municipal sewage.
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DOI：
10.2166/wst.2017.584
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发表时间：
2018-02
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影响因子：
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通讯作者：
Suprotim Das;S. Sarkar;Sanjeev Chaudhari
中科院分区：
文献类型：
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作者：
Suprotim Das;S. Sarkar;Sanjeev Chaudhari
上流式厌氧污泥毯（UASB）用于有机废水的处理已有几十年的历史。然而，UASB反应器在处理低强度废水（lws）时，由于产气量少导致混合不良，其性能很低。在本研究中，对UASB的设计进行了改进，以改善反应器液的混合，这对提高反应器的性能至关重要。改进的UASB （MUASB）反应器采用沿反应器高度与垂直壁面夹角为5.7°的倾斜挡板设计。对MUASB反应器内气液固三相流动进行了二维计算流体力学（CFD）模拟，并与常规UASB反应器进行了比较。CFD研究表明，与常规UASB相比，MUASB反应器在涡量量级上的混合更好，这也反映在反应器的性能上。比较了MUASB反应器与常规UASB反应器现场处理生活污水作为LSW的性能。与常规UASB反应器相比，MUASB反应器的总化学需氧量去除效率提高了约16%。因此，该MUASB模型证明了在LSW处理过程中混合与性能之间的定性关系。从这项研究来看，MUASB似乎有望在现场应用。
Up-flow anaerobic sludge blanket (UASB) has been in use since last few decades for the treatment of organic wastewaters. However, the performance of UASB reactor is quite low for treatment of low strength wastewaters (LSWs) due to less biogas production leading to poor mixing. In the present research work, a modification was done in the design of UASB to improve mixing of reactor liquid which is important to enhance the reactor performance. The modified UASB (MUASB) reactor was designed by providing a slanted baffle along the height of the reactor having an angle of 5.7° with the vertical wall. A two-dimensional computational fluid dynamics (CFD) simulation of three phase gas-liquid-solid flow in MUASB reactor was performed and compared with conventional UASB reactor. The CFD study indicated better mixing in terms of vorticity magnitude in MUASB reactor as compared to conventional UASB, which was reflected in the reactor performance. The performance of MUASB was compared with conventional UASB reactor for the onsite treatment of domestic sewage as LSW. Around 16% higher total chemical oxygen demand removal efficiency was observed in MUASB reactor as compared to conventional UASB during this study. Therefore, this MUASB model demonstrates a qualitative relationship between mixing and performance during the treatment of LSW. From the study, it seems that MUASB holds promise for field applications.