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Heterogeneity of the diverse aerobic sludge granules self-cultivated in a membrane bioreactor with enhanced internal circulation

Wu, Luying, Tang, Bing, Bin, Liying, Chen, Guangpeng, Huang, Shaosong, Li, Ping, Fu, Fenglian
Bioresource technology 2018 v.263 pp. 297-305
bacteria, chemical oxygen demand, fluorescence microscopes, granules, high-throughput nucleotide sequencing, membrane bioreactors, municipal wastewater, nitrogen content, scanning electron microscopy, sludge, wastewater treatment
The present work revealed the heterogeneity of the sludge granules formed in a membrane bioreactor with enhanced internal circulation, and also contributed to better understanding of their forming mechanisms. By continuously carrying out an experiment lasting for more than 3 months with the floc sludge from a local municipal wastewater treatment plant as inoculation sludge, diverse aerobic sludge granules were found to be successfully self-cultivated within the reactor. The results of scanning electron microscopy, fluorescence microscope and high-throughput sequencing measurement indicated that the obtained diverse granules exhibited quite obvious heterogeneity in their basic physico-chemical and microbial properties, and filamentous bacteria actually acted as a main skeleton to keep the self-cultivated sludge granules stable in both their structure and morphology. Furthermore, stable and high COD and TN removal achieved, over 85% and 60%, respectively, which confirmed its usefulness in wastewater treatment.