处理城市污水的好氧颗粒污泥培养及形成过程

在中试序列间歇式活性污泥法(SBR)反应器中采用有机物浓度低的城市污水培养好氧颗粒污泥. 运行过程中考察了污泥性能，并通过调整、优化沉淀时间和排水比等运行参数，培养出了高性能且稳定的好氧颗粒污泥. 活性污泥接种40 d后反应器内开始出现细小颗粒，160 d后颗粒污泥趋于成熟，粒径可达0.8 mm，且其周围有大量的原生动物. 颗粒化过程中，污泥密度、沉降速率和ρ(MLSS)分别从初期的1.004 0 g/cm3，6.8 m/h和4 000 mg/L升至1.010 5 g/cm3，38.5 m/h和8 000 mg/L，污泥容积指数(SVI₃₀)则从75 mL/g降至40 mL/g. 形成后的颗粒污泥对城市污水中COD_Cr和NH₄+-N有很好的去除效果，出水中ρ(COD_Cr)和ρ(NH₄+-N)分别在50和5 mg/L以下. 

Cultivation and Granulation Process of Aerobic Granular Sludge Applied to Treat Municipal Wastewater

In this study, low-strength municipal wastewater was used to cultivate aerobic granular sludge in a pilot-scale sequencing batch reactor (SBR). During the granulation process, the characteristics of the sludge were investigated, and the operation parameters such as settling time and volume exchange ratio were adjusted and optimized according to the characteristics of sludge in the reactor to cultivate high-powered and stable aerobic granular sludge. The granules with small size were observed in the reactor after 40 days’ cultivation. After 160 days’ cultivation, the granules became mature. Their maximum size reached 0.8 mm, and a mass of protozoa appeared around the granules. In the course of granulation, the specific gravity, settling velocity, and mixed liquor suspended solids (MLSS) mass concentration increased from 1.004 0 g/cm3, 6.8 m/h and 4 000 mg/L at the initial stage to 1.010 5 g/cm3, 38.5 m/h and 8 000 mg/L, respectively, while the sludge volumetric index (SVI₃₀) decreased from 75 mL/g to 40 mL/g. The concentrations of COD_Cr and NH₄+-N in the effluent from the granular reactor were below 50 and 5 mg/L, respectively, indicating high removal efficiencies of COD_Cr and NH₄+-N by the aerobic granular sludge.