Department of Biology, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, Denmark.
Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, Denmark.
Water Res. 2019 Jun 15;157:346-355. doi: 10.1016/j.watres.2019.03.065. Epub 2019 Mar 29.
Polyphosphate (poly-P) is a major constituent in activated sludge from wastewater treatment plants with enhanced biological phosphorus removal due to poly-P synthesis by poly-P accumulating organisms where it plays an important role for recovery of phosphorus from waste water. Our aim was to develop a reliable protocol for poly-P quantification by P NMR spectroscopy. This has so far been complicated by the risks of inefficient extraction and poly-P hydrolysis in the extracts. A protocol for complete extraction, identification and quantification of poly-P in activated sludge from a waste water treatment plant was identified based on test and evaluation of existing extraction protocols in combination with poly-P determination and quantification by solution and solid state P NMR spectroscopy. The total poly-P middle group content was quantified by solid state NMR for comparison with the poly-P middle groups quantified by solution NMR, which is novel. Three different extraction protocols previously used in literature were compared: 1) a single 0.25 M NaOH-0.05 M EDTA extraction, 2) a 0.05 M EDTA pre-extraction followed by a 0.25 M NaOH main extraction and 3) a 0.05 M EDTA pre-extraction followed by a 0.25 M NaOH-0.05 M EDTA main extraction. The results showed that the extraction protocol 2 was optimal for fresh activated sludge, extracting 10.8 ± 0.4 to 11.4 ± 1.2 mgP/gDW poly-P. Extraction protocols 1 and 3 extracted less than 9.4 ± 0.5 mgP/gDW poly-P. A comparison of the quantification of poly-P by P solution NMR and by P solid state NMR spectroscopy of lyophilised activated sludge showed 86 ± 9% extraction efficiency of poly-P, which confirms that the extraction protocol recovered most of the poly-P from the samples without pronounced poly-P degradation.
聚磷酸盐（poly-P）是强化生物除磷工艺中活性污泥的主要成分，聚磷积累菌通过合成 poly-P 来实现从废水中回收磷，因此在其中发挥着重要作用。我们的目的是开发一种可靠的聚磷酸盐定量分析方法，即 P 核磁共振光谱法。但迄今为止，由于提取过程中聚磷酸盐提取效率低和易水解，该方法的实施较为复杂。我们通过对现有提取方案的测试和评估，结合溶液和固态 P 核磁共振光谱法对聚磷酸盐的测定和定量分析，确定了一种从污水处理厂活性污泥中完全提取、鉴定和定量聚磷酸盐的方案。我们采用固态 NMR 定量分析活性污泥中的总聚磷酸盐中间群，与通过溶液 NMR 定量分析的聚磷酸盐中间群进行比较，这是一种新颖的方法。我们比较了三种不同的文献中使用过的提取方案：1）0.25 M NaOH-0.05 M EDTA 单一提取法；2）0.05 M EDTA 预提取法，然后是 0.25 M NaOH 主提取法；3）0.05 M EDTA 预提取法，然后是 0.25 M NaOH-0.05 M EDTA 主提取法。结果表明，对于新鲜的活性污泥，提取方案 2 是最优的，提取出 10.8±0.4 至 11.4±1.2 mgP/gDW 的聚磷酸盐。提取方案 1 和 3 提取的聚磷酸盐少于 9.4±0.5 mgP/gDW。对冻干活性污泥的 P 溶液 NMR 和 P 固态 NMR 光谱法定量分析聚磷酸盐的比较表明，聚磷酸盐的提取效率为 86±9%，这证实了该提取方案从样品中回收了大部分聚磷酸盐，而没有明显的聚磷酸盐降解。
