强化生物除磷系统中胞外聚合物的特性

胞外聚合物(EPS)在生物除磷过程中具有蓄磷能力,为进一步明确生物除磷系统中的EPS特性,以不具有明显除磷能力的全程好氧活性污泥系统(R1)的EPS作为对比,考察了具有良好除磷效果的厌氧/好氧交替下的强化生物除磷系统(R2)中EPS的理化特性.结果表明,相对于R1中的EPS主成分在一个周期内的不固定,R2中的蛋白质含量一直明显高于多糖含量;两者的主要荧光物质均为类蛋白质和类富里酸,但在好氧末期R2中类蛋白质的荧光强度高于R1; R1的EPS中Ca2+> Mg2+,而在R2中, Mg2+>Ca2+,同时R1中的Ca2+含量平均值为8.67mg/gMLSS,大于R2中Ca2+的平均值2.40mg/gMLSS;在好氧末期,R2中的TP为21.65mg/gMLSS,明显高于R1中的TP含量(13.83mg/g-MLSS).此外,R1和R2的zeta电位平均值分别为-36mV和-25mV.由此可见, EBPR系统中的EPS具有与全程好氧活性污泥中的EPS不同的特征.

Characteristics of EPS taken from an enhanced biological phosphorus removal system

EPS could act as a reservoir for phosphorus in biological phosphorus removal process. To better understand the physicochemical properties of EPS in the biological phosphorus removal system, two types of EPS taken from the systems that operated complete aerobically with little phosphorus removal ability (R1) and alternative anaerobically/aerobically with excellent phosphorus removal efficiency (R2) were studied. Results showed that protein was predominant in the EPS of R2, while the EPS from R1 was dominated by polysaccharides. Protein-like fluorophores and fulvic acid-like fluorophores were the main EEM spectra in both EPS types, whereas the fluorescence intensity of protein-like substances in R2 was higher than that of R1 at the end of aerobic phase. The content of Ca2+ was higher than Mg2+ in R1, while it was opposite in R2. Meanwhile, the average value of Ca2+ in R1 was 8.67mg/g-MLSS, higher than that of R2 (2.40mg/gMLSS) and the TP contents of R2 (21.65mg/gMLSS) was much higher than that in R1 (13.83mg/gMLSS) at the end of aeration. In addition, the zeta potential of R1 (-35mV) was more negative than that in R2 (-23mV).These results demonstrated that the characteristics of EBPR system was different from the complete-aerobic sludge system.