Zhang Chen, Sun Supu, Liu Xiang, Wan Chunli, Lee Duu-Jong
Shanghai Municipal Engineering Design General Institute, Shanghai, 200092, China.
Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China.
Environ Sci Pollut Res Int. 2017 Mar;24(8):7640-7649. doi: 10.1007/s11356-017-8417-7. Epub 2017 Jan 25.
Integrated aerobic granules were first cultivated in two sequencing batch reactors (SBRs) (A1 and A2). Then, A1's influent organic loading rate (OLR) was changed from alternating to constant (cycling time was still 6 h), while A2's cycling time varied from 6 to 4 h (influent OLR strategy remained alternating). After 30-day operation since the manipulative alternations, granule breakage happened in two reactors at different operational stages, along with the decrease of granule intensity. Granule diameter in A1 declined from the original 0.84 to 0.32 cm during the whole operation, while granules in A2 dwindled to 0.31 cm on day 22 with similar size to A1. Both the amount of total extracellular polymeric substances (EPSs) and the protein were declining throughout the operation, and the large molecular weight of protein was considered closely related to the stability of aerobic granules. The relative AI-2 level decreased at the same time, and influent OLR strategy might had more evident impact on quorum sensing (QS) ability of sludge compared with starvation period. Combined with microbial results, the decline of total EPS amount in two reactors could be concluded as follows: During the reactor operation, some functional bacteria gradually lost their dominance and were eliminated from the reactors, which finally caused granule disintegration. In summary, the results further confirmed that alternating OLR and proper starvation period were two major factors in effective cultivation and stability of aerobic granules from the perspective of QS.
在两个序批式反应器（SBRs）（A1和A2）中首次培养了集成好氧颗粒。然后，A1的进水有机负荷率（OLR）从交替变为恒定（循环时间仍为6小时），而A2的循环时间从6小时变为4小时（进水OLR策略仍为交替）。在操作改变后的30天运行中，两个反应器在不同运行阶段发生了颗粒破碎，同时颗粒强度下降。在整个运行过程中，A1中的颗粒直径从原来的0.84厘米降至0.32厘米，而A2中的颗粒在第22天缩小到0.31厘米，与A1的尺寸相似。在整个运行过程中，总胞外聚合物（EPSs）和蛋白质的含量都在下降，并且蛋白质的大分子重量被认为与好氧颗粒的稳定性密切相关。同时，相对AI-2水平下降，与饥饿期相比，进水OLR策略可能对污泥的群体感应（QS）能力有更明显的影响。结合微生物结果，两个反应器中总EPS量的下降可总结如下：在反应器运行期间，一些功能细菌逐渐失去其优势并从反应器中被淘汰，最终导致颗粒解体。总之，结果进一步证实，从QS的角度来看，交替OLR和适当的饥饿期是好氧颗粒有效培养和稳定性的两个主要因素。
