Bhatia Akansha, Singh Nitin Kumar, Bhando Timsi, Pathania Ranjana, Kazmi Absar Ahmad
a Department of Civil Engineering , Indian Institute of Technology , Roorkee , India.
b Department of Biotechnology , Indian Institute of Technology , Roorkee , India.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2017 Apr 16;52(5):440-448. doi: 10.1080/10934529.2016.1271665. Epub 2017 Jan 17.
In the present study, the effect of three intermittent aeration (IA) cycles on treatment performance and microbial diversity was investigated in an integrated fixed film activated sludge (IFAS) reactor treating municipal wastewater. The results showed that IA strategies were able to achieve efficient removal of organics and nitrogen ranging between 90 and 95% and 70 and 80%, respectively, however the phosphorus removal was found to be inversely proportional to the duration of aeration off time in each IA cycle. The microscopic analysis revealed that the suspended and attached biomass had compact morphology and open floc structure, respectively. For each gram of volatile suspended solids, 165 and 148 mg of extracellular polymeric substances (EPS) were extracted from attached and suspended biomass, respectively, constituting carbohydrates (∼24%), proteins (∼31%), humic acids (∼28%), DNA (∼2%) and unknown substances (∼12%). The microbial diversities of suspended biomass in IFAS reactor were investigated using culture-dependent approach, which confirmed the presence of Clostridium spp., Pseudomonas spp., Bacillus spp., Escherichia coli spp., Nitrosococcus spp., Streptococcus spp., Acinetobacter spp., Betaproteobacteria outliers, Klebsiella pneumoniae, Klebsiella aerogenes, Serratia marcescens, Micrococcus, Proteus vulgaris spp., Actinomycetes spp., and Actinobacteria including Micromonospora spp. and Streptomyces spp. Molecular tools for diversity analyses were used for ammonia and nitrite oxidizer identification, such as Nitrospira and Nitrosococcus species. Denitrifiers include the species of Pseudomonas, Betaproteobacteria and Flavobacterium. Acinetobacter, Betaproteobacteria and Gammaproteobacteria were responsible for the phosphorus removal in the present system. Overall, the system performed efficiently showing Proteobacteria (59%), Acinetobacter (12%) and Bacteroidetes (11%) as the dominant bacterial groups. However, the dominance of the bacterial diversity varied with the IA cycle time numerating the maximum percentage of bacterial species during IA1 phase i.e. 2.5 h aeration/0.5 h non-aeration.
在本研究中，在处理城市污水的一体化固定膜活性污泥（IFAS）反应器中，研究了三个间歇曝气（IA）周期对处理性能和微生物多样性的影响。结果表明，IA策略能够分别实现90%至95%和70%至80%的有机物和氮的高效去除，然而发现磷的去除与每个IA周期的曝气关闭时间成反比。微观分析表明，悬浮生物量和附着生物量分别具有致密形态和开放絮体结构。每克挥发性悬浮固体中，分别从附着生物量和悬浮生物量中提取了165毫克和148毫克的胞外聚合物（EPS），其组成包括碳水化合物（约24%）、蛋白质（约31%）、腐殖酸（约28%）、DNA（约2%）和未知物质（约12%）。采用基于培养的方法研究了IFAS反应器中悬浮生物量的微生物多样性，证实了梭菌属、假单胞菌属、芽孢杆菌属、大肠杆菌属、亚硝化球菌属、链球菌属、不动杆菌属、β-变形菌纲异常菌、肺炎克雷伯菌、产气克雷伯菌、粘质沙雷氏菌、微球菌属、普通变形杆菌属、放线菌属以及包括小单孢菌属和链霉菌属在内的放线菌纲的存在。使用多样性分析的分子工具来鉴定氨氧化菌和亚硝酸盐氧化菌，如硝化螺菌属和亚硝化球菌属的物种。反硝化菌包括假单胞菌属、β-变形菌纲和黄杆菌属的物种。不动杆菌属、β-变形菌纲和γ-变形菌纲在本系统中负责磷的去除。总体而言，该系统运行高效，变形菌门（59%）、不动杆菌属（12%）和拟杆菌门（11%）为主要细菌类群。然而，细菌多样性的优势随IA周期时间而变化，在IA1阶段（即曝气2.5小时/非曝气0.5小时）细菌种类的百分比最高。
