State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai 200092, PR China.
Water Res. 2013 Sep 15;47(14):5326-37. doi: 10.1016/j.watres.2013.06.013. Epub 2013 Jun 15.
Removal of nitrogen and phosphorus (P) from wastewater is successfully and widely practiced in systems employing both granular sludge technology and enhanced biological P removal (EBPR) processes; however, the key parameter, anaerobic reaction time (AnRT), has not been thoroughly investigated. Successful EBPR is highly dependent on an appropriate AnRT, which induces carbon and polyphosphate metabolism by phosphorus accumulating organisms (PAOs). Therefore, the long-term impact of AnRT on denitrifying P removal performance and granular characteristics was investigated in three identical granular sludge sequencing batch reactors with AnRTs of 90 (R1), 120 (R2) and 150 min (R3). The microbial community structures and anaerobic stoichiometric parameters related to various AnRTs were monitored over time. Free nitrite acid (FNA) accumulation (e.g., 0.0008-0.0016 mg HNO2-N/L) occurred frequently owing to incomplete denitrification in the adaptation period, especially in R3, which influenced the anaerobic/anoxic intracellular intermediate metabolites and activities of intracellular enzymes negatively, resulting in lower levels of poly-P and reduced activity of polyphosphate kinase. As a result, the Accumulibacter-PAOs population decreased from 51 ± 2.5% to 43 ± 2.1% when AnRT was extended from 90 to 150 min, leading to decreased denitrifying P removal performance. Additionally, frequent exposure of microorganisms to the FNA accumulation and anaerobic endogenous conditions in excess AnRT cases (e.g., 150 min) stimulated increased extracellular polymeric substances (EPS) production by microorganisms, resulting in enhanced granular formation and larger granules (size of 0.6-1.2 mm), but decreasing anaerobic PHA synthesis and glycogen hydrolysis. Phosphorus removal capacity was mediated to some extent by EPS adsorption in granular sludge systems that possessed more EPS, longer AnRT and relatively higher GAOs.
从废水去除氮和磷（P）在采用颗粒污泥技术和增强生物除磷（EBPR）工艺的系统中得到了成功和广泛的应用；然而，关键参数——厌氧反应时间（AnRT），尚未得到彻底研究。成功的 EBPR 高度依赖于适当的 AnRT，该时间通过聚磷菌（PAOs）诱导碳和聚磷酸盐代谢。因此，在三个相同的颗粒污泥序批式反应器中，研究了 AnRT 对反硝化除磷性能和颗粒特性的长期影响，AnRT 分别为 90（R1）、120（R2）和 150 min（R3）。随着时间的推移，监测了与各种 AnRT 相关的微生物群落结构和厌氧化学计量参数。在适应期，由于不完全反硝化，频繁发生游离亚硝酸（FNA）积累（例如，0.0008-0.0016 mg HNO2-N/L），尤其是在 R3 中，这对厌氧/缺氧细胞内中间代谢物和细胞内酶的活性产生负面影响，导致聚磷水平降低，多磷酸盐激酶活性降低。结果，当 AnRT 从 90 分钟延长至 150 分钟时，Accumulibacter-PAOs 种群从 51 ± 2.5%减少至 43 ± 2.1%，导致反硝化除磷性能下降。此外，在 AnRT 过长（例如 150 分钟）的情况下，微生物频繁接触 FNA 积累和厌氧内源性条件，刺激微生物产生更多的胞外聚合物物质（EPS），导致颗粒形成增强和颗粒增大（大小为 0.6-1.2 毫米），但减少了厌氧 PHA 合成和糖原水解。在具有更多 EPS、更长的 AnRT 和相对较高的 GAOs 的颗粒污泥系统中，磷去除能力在一定程度上受到 EPS 吸附的调节。
