Effect of nitrifiers community on fouling mitigation and nitrification efficiency in a membrane bioreactor
Effect of nitrifiers community on fouling mitigation and nitrification efficiency in a membrane bioreactor
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DOI：
10.1016/j.cep.2018.04.006
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发表时间：
2018-06-01
影响因子：
4.3
通讯作者：
Sarrafzadeh, Mohammad-Hossein
中科院分区：
文献类型：
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作者：
Sepehri, Arsalan;Sarrafzadeh, Mohammad-Hossein
膜生物反应器（MBR）中的膜污染通常取决于微生物细胞密度和微生物种群结构。通过对常规活性污泥（CAS）进行特定的投加氨氮，获得了硝化活性污泥（NAS）。其次，通过与CAS系统的比较，研究了NAS系统中自养硝化菌的优势，并比较了其高硝化效率（100%对43%）和低COD去除率（9%对65%）。CAS和NAS系统在相同氨氮浓度下产生的最大N-NO3-量分别为6.6mg/L和37.5mg/L。在MLSS浓度为2000 mg/L的条件下，分别采用不同NAS和CAS投加量的错流过滤系统和简单死端过滤系统进行了过滤性能试验。NAS的可过滤性是CAS的两倍。CAS系统中的可溶性微生物产物（SMP）和胞外聚合物（EPS）含量显著高于NAS系统（NAS系统为2和6 mg/L，CAS系统为100和36 mg/L）。通过增加硝化菌的比例，膜生物反应器的渗透能力提高了2.5倍，运行时间延长了约一倍（6 ~ 11.5h）。结果表明，适当的C/N比可以有效地控制膜生物反应器中微生物的数量，并使硝化菌能够有效地减缓膜生物反应器的污染。
Membrane fouling in membrane bioreactors (MBR) normally depends on the microbial cell density and microbial population structure. A nitrifying-enriched activated sludge (NAS) was obtained in this study through particular ammonium feeding of conventional activated sludge (CAS). Next, the dominance of autotrophic nitrifler population in NAS system was checked and compared with CAS system by its high nitrification efficiency (100% vs. 43%) and low COD removal (9% vs. 65%). Furthermore, the maximum amount of N-NO3-produced from similar concentrations of ammonium in CAS and NAS systems were 6.6 mg/L and 37.5 mg/L, respectively. A filterability test also was done in the cross-flow and simple dead-end filtration systems proportionally employing different amount of NAS and CAS with a constant MLSS concentration of 2000 mg/L. NAS was twice as filterable compared to CAS. Soluble microbial products (SMP) and extracellular polymeric substance (EPS) in CAS were significantly higher than NAS system (2 and 6 mg/L for NAS vs.100 and 36 mg/L for CAS). By increasing the proportion of nitrifying bacteria, the permeation was enhanced remarkably about 2.5 folds and the operation time of MBR was approximately doubled (6-11.5 h). The results indicated that an appropriate C/N ratio can control the microbial population and help the nitrifier significantly mitigate fouling in MBR.