Abstract In this study, conventional and novel gas sparging regimes have been evaluated for a municipal wastewater granular anaerobic MBR to identify how best to achieve high sustainable fluxes whilst simultaneously conserving energy demand. Using continuous gas sparging in combination with continuous filtration, flux was strongly dependent upon shear rate, which imposed a considerable energy demand. Intermittent gas sparging was subsequently evaluated to reduce energy demand whilst delivering an analogous shear rate. For a flux of 5 L m−2 h−1, a fouling rate below 1 mbar h−1 was sustained with low gas sparging frequency and gas sparging rates. However, to sustain low fouling rates for fluxes above 10 L m−2 h−1, a gas sparging frequency of 50% (i.e. 10 s on/10 s off) and an increase in gas sparging rate is needed, indicating the importance of shear rate and gas sparging frequency. An alternative gas sparging regime was subsequently tested in which filtration was conducted without gas sparging, followed by membrane relaxation for a short period coupled with gas sparging, to create a pseudo dead-end filtration cycle. Fouling characterisation evidenced considerable cake fouling rates of 200–250 mbar h−1 within each filtration cycle. However, long term fouling transient analysis demonstrated low residual fouling resistance, suggesting the cake formed during filtration was almost completely reversible, despite operating at a flux of 15 L m−2 h−1, which was equivalent or higher than the critical flux of the suspension. It is therefore asserted that by operating filtration in the absence of shear, fouling is less dependent upon the preferential migration of the sub-micron particle fraction and is instead governed by the compressibility of the heterogeneous cake formed, which enables higher operational fluxes to be achieved. Comparison of energy demand for the three gas sparging regimes to the energy recovered from municipal wastewater AnMBR demonstrated that only by using dead-end filtration can energy neutral wastewater treatment be realised which is the ultimate ambition for the technology.

中文翻译：

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确定颗粒厌氧膜生物反应器的气体喷射方式，以实现能源中性城市污水处理

摘要 在这项研究中，对城市污水颗粒厌氧 MBR 的传统和新型气体喷射机制进行了评估，以确定如何最好地实现高可持续通量，同时节省能源需求。使用连续气体喷射与连续过滤相结合，通量强烈依赖于剪切速率，这会产生相当大的能量需求。随后评估间歇性气体喷射以减少能量需求，同时提供类似的剪切速率。对于 5 L m-2 h-1 的通量，低于 1 mbar h-1 的结垢率在较低的气体喷射频率和气体喷射速率下得以维持。然而，为了维持高于 10 L m-2 h-1 的流量的低结垢率，需要 50% 的气体喷射频率（即 10 s on/10 s off）和增加气体喷射率，表明剪切速率和气体喷射频率的重要性。随后测试了另一种气体喷射方式，其中在没有气体喷射的情况下进行过滤，然后膜松弛短时间与气体喷射相结合，以创建假死端过滤循环。结垢特征表明，在每个过滤循环中，滤饼结垢率为 200–250 mbar h-1。然而，长期污垢瞬态分析表明残余污垢阻力低，表明过滤过程中形成的滤饼几乎完全可逆，尽管在 15 L m-2 h-1 的通量下运行，该通量等于或高于过滤器的临界通量。暂停。因此断言，通过在没有剪切的情况下进行过滤，结垢较少依赖于亚微米颗粒部分的优先迁移，而是由形成的异质饼的可压缩性控制，从而能够实现更高的操作通量。三种气体喷射方式的能源需求与从城市废水中回收的能源的比较 AnMBR 表明，只有使用死端过滤才能实现能源中性废水处理，这是该技术的最终目标。