表层附着累枝虫的好氧颗粒污泥特性

在序批式反应器(SBR)中处理实际生活污水,并接种城市污水处理厂活性污泥,培养出表层附着大量累枝虫的好氧颗粒污泥.运行120 d时,颗粒污泥浓度可达4482 mg·L-1,污泥容积指数(SVI)为55 m L·g-1左右,颗粒的粒径主要在1.6~2.5 mm之间,平均沉速为55.4 m·h-1,累枝虫密度可达30450 ind·m L-1.CODCr和NH+4-N的平均去除率分别为87.9%和91.8%.采用直接免疫荧光法证实累枝虫可吞食游离细菌,能有效减少出水SS,且出水SS与累枝虫的密度变化整体呈相反趋势.表层附着生长的累枝虫略微降低了颗粒污泥的沉速.结构分析可看出累枝虫根植于颗粒表层,柄的部分成为颗粒污泥的"骨架",有利于颗粒污泥结构强度和稳定性.

Characteristics of aerobic granular sludge with Epistylis adherent to the surface

After the inoculation of activated sludge from a municipal sewage treatment plant, the aerobic granular sludge with a number of Epistylis adherent to the surface was cultivated in a sequencing batch reactor (SBR) which was used to treat domestic wastewater. Running for 120 d, the concentration of the aerobic granular sludge reached 4482 mg · L^-1. The value of SVI was around 55 mL · g^-1. The diameters of the granules mainly ranged from 1.6 to 2.5 mm. The average settling velocity was 55.4 m · h^-1. Meanwhile, the density of Epistylis reached 30450 ind · mL^-1. The average removal efficiencies of COD_Cr and NH₄⁺-N were 87.9% and 91.8%, respectively. The direct immune fluorescence method confirmed that Fluorescein Isothiocyanate (FTIC)-labeled free bacteria can be ingested by Epistylis. The suspended solids (SS) of the effluent decreased accordingly. Furthermore, the overall trends of the effluent SS and the density of Epistylis were opposite. The settling velocity of the granular sludge was slightly reduced by Epistylis adherent to the surface. The structure analysis indicated that Epistylis rooted in the surface of the granules and the stalks served as the "skeleton" of the granular sludge, which was beneficial to the structure strength and stability of aerobic granular sludge.