基于磷回收的低温微氧EBPR系统的表观与微观特性

在低溶解氧(DO = 1mg/L)条件下启动2个厌氧/好氧交替运行的SBR(A/O-SBR),中温(22±1)℃SBR1和低温(14±1)℃SBR2,考察侧流磷回收工艺对低耗主流强化生物除磷(EBPR)系统污染物去除性能?微生物种群结构和磷回收潜能的影响.结果表明,SBR1和SBR2的脱氮及COD去除性能未受磷回收操作的影响,但是在除磷方面,SBR1的EBPR性能更稳定,对侧流磷剥夺更耐受,平均除磷率达90.7%,而SBR2在侧流磷回收阶段的平均除磷率为78.4%.此外,基于侧流磷回收的微氧EBPR系统可在低温下保持较为稳定的生物质浓度(VSS),但实施侧流磷回收后SVI值由104.6mL/g升至216.8mL/g,系统发生污泥膨胀.基于16S rRNA的高通量测序结果表明,主流系统的微生物种群结构在侧流磷回收阶段发生了较大变化,Candidatus Competibacter?Flavobacterium(黄杆菌属)和Dechloromonas(脱氯单胞菌属)骤增,Candidatus Accumulibacter的相对丰度从12.5%降至6.4%.经计算,在1/3侧流比前提下SBR1与SBR2的磷回收潜能分别为68.8%和69.4%.总的来说,微氧EBPR系统的运行温度是保证侧流磷回收稳定进行所要考虑的重要因素之一.

Apparent and microscopic performance of low temperature and low dissolved oxygen EBPR system subjected to side-stream phosphorus recovery

Two alternative anaerobic/oxic SBR (A/O-SBR) reactors controlled at medium temperature (22±1)℃SBR1and low temperature (14±1)℃SBR2were operated to investigate the effect of side-stream phosphorus recovery on nutrients removal performance, microbial community structure and phosphorus recovery potential of mainstream EBPR systems under low dissolved oxygen (DO = 1mg/L). The results showed that the nitrogen and COD removal performance of SBR1and SBR2 were not influenced by the introduction of side-stream phosphorus recovery. In terms of phosphorus removal, however, EBPR performance of SBR1was more stable and more tolerant to phosphorus deprivation. During the phase of side-stream phosphorus recovery, the average efficiency of phosphorus removal in SBR1reached 90.7%, while SBR2 was 78.4%. It was also found that microaerobic EBPR subjected to side-stream phosphorus recovery could maintain a relatively stable volatile suspended solids (VSS) concentration at low temperature. While the value of SVI increased from 104.6mL/g to 216.8mL/g after side-stream phosphorus recovery, resulting in sludge bulking in SBR2 system. The result of high-throughput sequencing based on 16S rRNA showed that the microbial community structure of the mainstream system changed significantly after side-stream phosphorus recovery. The relative abundances of Candidatus Competibacter, Flavobacterium and Dechloromonas rapidly increased and Candidatus Accumulibacter fell from 12.5% to 6.4%. It was estimated that the average phosphorus recovery potential of SBR1 and SBR2 were 68.8% and 69.4%, respectively, with the side-stream ratio of 1/3. In a conclusion, the temperature was one of the important factors to ensure the stable operation of side-stream phosphorus recovery in an EBPR system under low DO.