Effects of Different Carbon Source on the Performance and Microbial Community of EBPR during Start-Up Period

In order to analysis the impact of different carbon source on the performance and microbial community of Enhanced biological phosphorus removal (EBPR) start-up period, 4 laboratory scale sequencing batch reactors (SBR) supplied with different carbon source were operated. SBR1 (fed with switched carbon source between acetate and propionate) quickly achieved enhanced phosphorus removal efficiency, the phosphate removal rate reached 95% at 50^th day, while SBR2(fed with glucose as a sole carbon source) still remained about 50% at the same time. DGGE analysis revealed the number of major bands of SBR1 and SBR2 decreased during the start-up period, thus their microbial community were getting simpler. The quantity of populations of PAOs and GAOs in each SBR was detected with FISH, it was revealed that PAOs increased rapidly in SBR1 on 27^th d and 50^th d, and finally reached 57%. Population of PAOs in SBR2 reached 20% on 42^th d and kept stability. While only 7% and 4.5% appeared in SBR3 and SBR4, respectively. This study showed that different carbon source had a significant impact on the microbial community structure succession, and carbon source switched between acetate and propionate had significant advantage over glucose and waste-water in the EBPR start-up period.