Evaluating influence of filling fraction of carriers packed in anaerobic side-stream reactors on membrane fouling and microbial community of the coupled membrane bioreactors

• Published in: Journal of hazardous materials Vol. 388; p. 122030
• Main Authors: Zheng, Yue, Zhou, Zhen, Jiang, Lingyan, Huang, Jing, Jiang, Jie, Chen, Yirong, Shao, Yanjun, Yu, Siqi, Wang, Kaichong, Huang, Jianping, Wang, Zhiwei
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.04.2020
• Subjects: Ammonium Compounds; Anaerobic side-stream reactor; Anaerobiosis; Biofouling; Bioreactors - microbiology; Carriers; Extracellular Polymeric Substance Matrix; Fouling; Membrane bioreactor; Membranes, Artificial; Microbiota; Nitrogen; Phosphorus; Sewage; Sludge reduction; Waste Disposal, Fluid; Water Pollutants, Chemical; Carriers; Sludge reduction; Membrane bioreactor; Fouling; Anaerobic side-stream reactor
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2020.122030

[Display omitted] •Anaerobic side-stream reactor (ASSR) coupled MBR was proposed for sludge reduction.•Effect of filling fractions of carriers in ASSR on membrane fouling (MF) was studied.•25 % carriers alleviated MF by promoting hydrolysis and reducing sludge viscoelastic.•50 % carriers improved MF little due to the increase of shear forces to biofilm.•MiSeq revealed biomarkers related to severe MF easily attached on membrane surface. An anoxic/oxic membrane bioreactors (AO-MBR) and three identical anaerobic side-stream reactor coupled with anoxic/oxic membrane bioreactors (ASSR-MBR) were constructed and operated in parallel to investigate the appropriate filling fraction of carriers packed in ASSR, influences on pollutants removal, sludge reduction, membrane fouling and microbial community of ASSR-MBR. Inserting ASSR achieved efficient COD removal and nitrification, and packing carriers in ASSR obtained the highest sludge reduction efficiency of 50.5 % at filling fraction of 25 %. Compared to AO-MBR, inserting ASSR without carriers induced the release of viscous components in extracellular polymeric substances (EPS) and the formation of calcium carbonate-related bacteria on membrane surface, and thus deteriorated membrane fouling. Packing carriers with 25 % filling fraction promoted the hydrolysis of soluble microbial products and EPS, whilst reduced the viscoelasticity of sludge flocs. Higher filling fraction of 50 % increased the shear forces to the biofilm and biomarkers related to membrane fouling, and thus showed little improvement to alleviate membrane fouling. MiSeq sequencing revealed that although it enriched in the bulk sludge of conventional ASSR-MBR and the coupled reactor with filling fraction of 50 %, the floc-forming, hydrolytic and fermentative bacteria were more inclined to attach on the membrane surface and alleviate fouling process.