| Title | Factors affecting the growth of Microthrix parvicella: Batch tests using bulking sludge as seed sludge |
| Abstract | Sludge bulking caused by the overgrowth of filamentous bacteria, particularly Microthrix parvicella, is one of the challenges for the stable operation of municipal wastewater treatment plants (WWTPs). The driving forces for the development of sludge bulking, however, have not been well understood because of the extremely low growth rate of M. parvicella. In this study, batch experiments were performed using bulking sludge (sludge volume index (SVI), around 185 mL g(-1)) from a full-scale WWTP as the seed sludge to investigate the influences of carbon source, anaerobic/aerobic alternation condition and temperature on the growth of M. parvicella. The qPCR results showed that the use of oleic acid as carbon source, anaerobic/aerobic alternation treatment and low temperature (13 degrees C) were favorable conditions for maintaining the dominance of M. parvicella in the tested activated sludge. Under these conditions, the SVI values remained at comparatively high values of 170.5 mL g(-1), 162.5 mL g(-1) and 129.5 mL g(-1) after operation for approximately two months, and the relative abundances of M. parvicella were 36.7%, 9.74% and 34.07%, respectively, in comparison with the initial values of 33.04%, 29.29% and 54.66%. However, the relative abundances of M. parvicella decreased to 0.86-4.44%, 0.7% and 4.94%, respectively, under the conditions of other carbon sources, aerobic-only treatment and a temperature of 20 degrees C. The FISH analysis gave a similar result. This study was performed with mixed sludge under controlled operating conditions, which provided a valuable information for the pure culture of M. parvicella and further investigations on its physiology and metabolism. (C) 2017 Elsevier B.V. All rights reserved. |
| Source | Science of the total environment 609, pp. 1192–1199 |
| Keywords | Bulking sludgeMicrothrix parvicellaAnaerobic/aerobic alternation conditionactivated sludge |
| Journal | Science of the total environment |
| Editor | Elsevier, Lausanne ;, Paesi Bassi |
| Year | 2017 |
| Type | Articolo in rivista |
| DOI | 10.1016/j.scitotenv.2017.07.261 |
| Authors | Fan, Niansi; Qi, Rong; Rossetti, Simona; Tandoi, Valter; Gao, Yingxin; Yang, Min |
| Text | 379093 2017 10.1016/j.scitotenv.2017.07.261 ISI Web of Science WOS 000410352900123 Bulking sludge Microthrix parvicella Anaerobic/aerobic alternation condition activated sludge Factors affecting the growth of Microthrix parvicella Batch tests using bulking sludge as seed sludge Fan, Niansi; Qi, Rong; Rossetti, Simona; Tandoi, Valter; Gao, Yingxin; Yang, Min Chinese Acad Sci; Univ Chinese Acad Sci; Water Research Institute, IRSA CNR Sludge bulking caused by the overgrowth of filamentous bacteria, particularly Microthrix parvicella, is one of the challenges for the stable operation of municipal wastewater treatment plants WWTPs . The driving forces for the development of sludge bulking, however, have not been well understood because of the extremely low growth rate of M. parvicella. In this study, batch experiments were performed using bulking sludge sludge volume index SVI , around 185 mL g 1 from a full scale WWTP as the seed sludge to investigate the influences of carbon source, anaerobic/aerobic alternation condition and temperature on the growth of M. parvicella. The qPCR results showed that the use of oleic acid as carbon source, anaerobic/aerobic alternation treatment and low temperature 13 degrees C were favorable conditions for maintaining the dominance of M. parvicella in the tested activated sludge. Under these conditions, the SVI values remained at comparatively high values of 170.5 mL g 1 , 162.5 mL g 1 and 129.5 mL g 1 after operation for approximately two months, and the relative abundances of M. parvicella were 36.7%, 9.74% and 34.07%, respectively, in comparison with the initial values of 33.04%, 29.29% and 54.66%. However, the relative abundances of M. parvicella decreased to 0.86 4.44%, 0.7% and 4.94%, respectively, under the conditions of other carbon sources, aerobic only treatment and a temperature of 20 degrees C. The FISH analysis gave a similar result. This study was performed with mixed sludge under controlled operating conditions, which provided a valuable information for the pure culture of M. parvicella and further investigations on its physiology and metabolism. C 2017 Elsevier B.V. All rights reserved. 609 Published version Fan et al 2017 Factors affecting the growth of Microthrix parvicella Batch tests using bulking sludge as seed sludge Fan et al Stoten 2017.pdf Articolo in rivista Elsevier 0048 9697 Science of the total environment Science of the total environment Sci. total environ. simona.rossetti ROSSETTI SIMONA |
