Rheological behavior of the sludge in a long-running anaerobic digestor: Essential factors to optimize the operation

• Published in: Biochemical engineering journal 2016-10, Vol.114, p.147-154
• Main Authors: Feng, Xianfeng, Tang, Bing, Bin, Liying, Song, Haoliang, Huang, Shaosong, Fu, Fenglian, Ding, Jiewei, Chen, Cuiqun, Yu, Chunfei
• Format: Article
• Language: English
• Subjects: Anaerobic digestion; Apparent viscosity; Bioreactor; Rheological behavior; Thixotropic index; Torque
• ISSN: 1369-703X; 1873-295X
• DOI: 10.1016/j.bej.2016.06.022

[Display omitted] ⿢A real-time online torque monitoring system was established.⿢The rheological behavior of sludge in a long-running digestor was revealed.⿢Variations of different rheological parameters over time were described in detailed.⿢Contents of TSS and EPS have close relationships with the limit viscosity of sludge.⿢Thixotropic index in a long running anaerobic digestor was analyzed. This work investigated the rheological behavior of sludge in a long-running digestor and established a timely approach for monitoring the torque information of an anaerobic process. With multi-methods, the rheological behavior of sludge within the digestor were revealed, which indicated that: (1) the on-line torque sensing approach was an efficient method to obtain timely torque signals, which could give a reliable prediction to the variation in the rheological behavior of sludge, and further provide useful information to monitor the operation of an anaerobic digestor; (2) the thixotropic index of sludge in the digestor decreased continuously along with the operational time, which showed a weakening tendency in the interaction among sludge particles; (3) both the content of total suspended solids (TSS) and extracellular polymeric substances (EPS) had close relationships with the limit viscosity of sludge, but TSS showed a positive impact, while, the impact of EPS was negative.