聚磷菌富集实验及其内源特征探究

通过磷酸盐释放速率(PRR)测定、荧光原位杂交技术(FISH)及LIVE/DEAD细胞染色技术,分别研究了生物营养物去除(BNR)系统与富集聚磷菌(PAOs)序批式反应器(SBR)系统中PAOs在好氧环境下的衰减特征.结果表明,当富集聚磷菌SBR系统进料中碳源(三水合乙酸钠和丙酸)是以36d为一个循环周期方式投加时,即三水合乙酸钠24d和丙酸12d,系统中PAOs富集比例可达91%.测定与计算结果表明,生物营养物去除(BNR)系统与富集聚磷菌SBR系统中PAOs衰减速率分别为0.113d-1和0.181d-1,死亡速率分别为0.048d-1和0.036d-1.这说明由细胞死亡引起的PAOs数量衰减在两个系统中分别占细胞总衰减的42%(BNR)和20%(SBR),而由细胞活性降低引起的活性衰减分别占细胞总衰减的58%(BNR)和80%(SBR).由此可见,PAOs数量衰减在其细胞总衰减中只占较小一部分,而绝大部分衰减是由活性衰减所引起.

Enriched experiment and endogenous characteristics of polyphosphate-accumulating organisms(PAOs)

By means of measuring maximal anaerobic phosphate release rates (PRR), analyzing 16S rRNA with fluorescence in-situ hybridization (FISH) and observing membrane integrity by live/dead staining, the aerobic decay characteristics of polyphosphate-accumulating organisms (PAOs) in a biological nutrient removal (BNR) system and an enriched PAOs sequencing batch reactor (SBR) system were investigated. It was experimentally determined that a highly enriched culture of PAOs (91%) was obtained in the enriched PAO-SBR system by alternating the carbon source in the feed between sodium acetate trihydrate and propionate over a 36 d switching cycle, i.e., sodium acetate trihydrate (24 d) and propionate (12 d). The experimental results and calculations revealed that the decay rates of PAOs in the BNR and enriched PAO-SBR systems were 0.113 d-1 and 0.181 d-1, respectively, and the death rates were 0.048 d-1 and 0.036 d-1. In addition, the results also demonstrated that cell death contributed 42% and 20%, respectively, to the cell decay in the BNR and enriched PAO-SBR systems. In other words, the activity decay accounted for 58% and 80% of the total cell decay. For this reason, cell death was not a major factor causing the cell decay of PAOs, but activity decay was mostly responsible for this process.