低基质颗粒污泥反应器中亚硝化的实现过程及其污泥变化特征

在CSTR反应器中接种硝化颗粒污泥处理低氨氮浓度废水，研究其亚硝化的实现过程，并基于对颗粒污泥理化性质、功能菌群的空间分布规律及活性的分析，系统阐述了影响亚硝化稳定的关键因素.结果表明，通过协同调控进水氨氮负荷（NLR）和溶解氧（DO）水平等参数，亚硝化成功实现并可维持稳定，亚硝积累率达80%以上.所得亚硝化颗粒污泥为棕黄色，呈现出光滑、饱满的椭球形或球形，颗粒表面微生物以球菌为主；颗粒平均粒径1.3 mm，平均沉降速率为71.3 m·h^-1.批次试验显示，颗粒污泥（粒径>0.8 mm）中存在明显的成层分布结构，氨氧化细菌（AOB）主要占据颗粒表层空间，而亚硝酸盐氧化细菌（NOB）主要分布在颗粒内部；絮体或小粒径污泥（粒径<0.8 mm）与颗粒污泥（粒径>0.8 mm）呈现出不同的微生物空间分布特征.在颗粒污泥反应器中，良好的硝化菌群分层结构、较高的出水氨氮浓度（15~33 mg·L^-1）或较低的DO/NH₄⁺-N （0.08~0.15）是亚硝化实现过程中的关键影响因素.

Realization Process of Nitritation and Changes in Sludge Characteristics in Granular Sludge Reactor for Low Strength Sewage Treatment

The realization process of nitritation was studied in a CSTR reactor seeding with nitrification granular sludge to treat low ammonia sewage. During the operation period, the physical and chemical properties, the spatial distribution of functional microbes, and the activity of the granular sludge were also investigated to elaborate the main factors for the stability of nitritation. The results showed that nitritation can be successfully achieved and maintained by the cooperative controlling of nitrogen loading rate (NLR) and dissolved oxygen (DO) levels, and the nitrite accumulation rate was over 80%. The obtained nitritation granular sludge was brownish yellow, showing a smooth, full ellipsoid or sphere, and the microorganisms on the surface of the particles were mainly cocci; the average particle size was 1.3 mm, and the average sedimentation rate was 71.3 m·h^-1. Batch tests showed that there was a significant stratified distribution structure in granular sludge (particle size >0.8 mm), the ammonia-oxidizing bacteria (AOB) mainly occupied the surface space of the particles, and the nitrite-oxidizing bacteria (NOB) were mainly distributed inside the particles. Flocs or small-size sludge (particle size<0.8 mm) and granular sludge (particle size >0.8 mm) exhibit different spatial distribution characteristics of microorganisms. In the granular sludge reactor, well stratification of the nitrifier guilds, high level of residual ammonia concentrations in effluent (15-33 mg·L^-1), or low ratio between DO and NH₄⁺-N concentrations (0.08-0.15) should be key influencing factors in the process of achieving nitritation.