Performance of a tertiary submerged membrane bioreactor operated at supra-critical fluxes
Performance of a tertiary submerged membrane bioreactor operated at supra-critical fluxes
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DOI：
10.1016/j.memsci.2014.01.027
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发表时间：
2014-05
影响因子：
9.5
通讯作者：
L. Vera;E. González;O. Díaz;S. Delgado
中科院分区：
文献类型：
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作者：
L. Vera;E. González;O. Díaz;S. Delgado
以中试规模的浸没式好氧膜生物反应器（MBR）为研究对象，考察了MBR在超临界通量下运行的可持续性。采用膜生物反应器对某污水处理厂二级出水进行深度处理。该系统成功地操作，没有生物质吹扫在水力停留时间（HRT）为8.8小时，导致在一个中等的液体悬浮固体浓度范围（MLSS=4.1-7.1克/升）的生物反应器，根据流入的有机负荷波动。处理性能稳定，实现了较高的铵氮转化率（96%）和溶解性有机碳去除率（53%）。根据改进的通量阶跃法进行了短期试验，以确定临界通量和评价最佳膜循环曝气频率。对于长期测试，基于预先选择的跨膜设定点，应用了反冲洗启动的替代操作模式。在典型的特定需求值（SADpnet=13.7-18.3 N m3/m3）下，可以在不同的超临界过滤通量（J=60-80 l/h m2）和反冲洗通量（40-80 l/h m2）下保持连续操作，而无需任何化学清洗。在类似的水动力条件下，通过实验室规模试验中的污泥分级进行的分析表明，悬浮固体对滤饼膜污染的贡献估计约为86- 89%。
A pilot-scale submerged aerobic membrane bioreactor (MBR) was run for over 3 months to assess the sustainability to operate at supra-critical fluxes. The MBR was applied as advanced treatment of secondary effluent from a conventional wastewater treatment plant. The system was successfully operated without biomass purge at hydraulic retention time (HRT) of 8.8 h, resulting in a moderate liquor suspended solid concentrations range (MLSS=4.1–7.1 g/l) in the bioreactor, according to the influent organic load fluctuations. Treatment performance was stable and achieved high conversion of ammonium to nitrate (96%) and dissolved organic carbon removal (53%). Short-term tests have been carried out according to a modified flux-step method to determine critical flux and evaluating optimum membrane cyclical aeration frequency. For the long-term tests, an alternative operation mode for backwashing initiation, based on a pre-selected transmembrane set-point, was applied. Under typical specific demand values (SADpnet=13.7–18.3 N m3/m3), continuous operation under different supra-critical filtration fluxes (J=60–80 l/h m2) and backwashing fluxes (40–80 l/h m2) can be maintained without any chemical cleaning. Analysis by means of sludge fractionation in lab-scale tests, at similar hydrodynamic conditions, indicated that the contribution of suspended solids to cake membrane fouling was estimated about 86–89%.