采用无机碳作为基质在SBR反应器内培养好氧颗粒污泥,考察了氨氧化菌(AOB)、硝化菌(NOB)在颗粒密实化过程中的变化规律及其对颗粒化的影响.研究发现自养菌形成的颗粒污泥极为密实,其密度高达1.06 g/mL,扫描电镜结果表明棒状菌是其优势菌群.出水的氨氮、亚硝酸氮及硝酸氮浓度分别为4.5-15.2 mg/L、10.2-20.3 mg/L和17.9-30.1 mg/L,氨氮的去除率为78%-92%.通过分析反应器内不同形态氮的变化曲线及变化速度,发现在实验初期较短的沉淀时间是AOB富集的主要因素,且颗粒的形成与AOB的富集无明显的相关性.与此相反,硝化速率与颗粒的形成有明显的相关性,颗粒形成有利于固定NOB,其代谢产物可以促进颗粒稳定化,因此,颗粒化与NOB之间存在相互促进的作用.另外,本研究还发现自养反硝化作用随着颗粒的形成而逐步得以强化.
Autotrophic granular sludge was developed in an SBR reactor using inorganic carbonal substrate.The variation of ammonia-oxidizing bacteria(AOB) and nitriteoxidizing bacteria(NOB) during the densification process and their effects on granulation have been evaluated.It was found that the autotrophic bacteria granular sludge was compact with the density reached up to 1.06 g/mL,and the rod-like bacteria predominated in granules on the evidence of scanning electron microscopic(SEM) results.Ammonia,nitrite and nitrate in the effluent were 4.5-15.2 mg/L,10.2-20.3 mg/L and 17.9-30.1 mg/L,respectively,and the ammonia removal efficiency was 78%-92%.By evaluating the profile of various types of nitrogen and their conversion rates,it was found that short settling time was the main factor that enriched the AOB at the beginning of this experiment,and the granulation did not correlate with AOB.On the contrary,nitrification rate well correlated with granulation,and evidence demonstrated that the formation of granulation was in favorate of imoblization of NOB and the metabolite of NOB stabilized granules,therefore granules and NOB mutually enhanced.Additionally,it was found that the autotrophic denitrification was gradually increased with the process of granulation.