Effect of sludge properties on the filtration characteristics of self-forming dynamic membranes (SFDMs) in aerobic bioreactors: Formation time, filtration resistance, and fouling propensity

• Published in: Journal of membrane science Vol. 436; pp. 186 - 194
• Main Authors: Liang, Shuang, Qu, Luojuan, Meng, Fangang, Han, Xueli, Zhang, Jian
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.06.2013; Elsevier
• Subjects: artificial membranes; bioreactors; carbohydrate content; carbohydrates; Chemistry; Colloidal state and disperse state; Exact sciences and technology; filters; filtration; fouling; General and physical chemistry; hydrophobic bonding; hydrophobicity; Membrane bioreactor; Membrane formation; Membrane fouling; Membranes; oxygen; particle size distribution; Porous materials; Self-forming dynamic membranes; sludge; Sludge properties; statistical analysis; viscosity; wastewater treatment; Membrane bioreactor; Self-forming dynamic membranes; Sludge properties; Membrane formation; Membrane fouling; Viscosity; Oxygen; Statistical analysis; Fouling; Filtration; Hydrophobic interaction; Hydrophobicity; Porous material; Membrane reactor; Bioreactor; Particle size distribution; Pore; Filter; Carbohydrate; Waste water purification; Deposition; Rheological properties
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2013.02.021

This study attempts to elucidate the effect of sludge properties on the formation time, filtration resistance, and fouling propensity of self-forming dynamic membranes (SFDMs), developed on coarse-pore filters in aerobic wastewater treatment bioreactors. Short-term filtration experiments were performed with twenty aerobic sludge samples having twelve sludge properties characterized. Statistical analysis showed that mean particle diameter (Dvm) associated with particle size distribution strongly affected both formation time (rp=−0.803, p=0.000) and filtration resistance (rp=−0.733, p=0.000) of SFDMs, whereas relative hydrophobicity (RH) exhibited a moderate correlation with SFDM formation time (rp=−0.487, p=0.029). In contrast, four other different sludge properties, i.e. viscosity (rp=0.811, p=0.000), extractable extracellular polymeric substances (eEPS) (rp=0.723, p=0.000), the carbohydrate content of eEPS (rp=0.766, p=0.000), and specific oxygen uptake rate (SOUR) (rp=−0.610, p=0.004), were identified as having significant impact on the fouling propensity of fresh SFDMs. Besides statistical analysis, more detailed experimental evidences were obtained by directly examining the identified important properties of fresh and initially fouled SFDMs. Sludge deposition during SFDM formation appears to be dominated by permeate drag force and hydrophobic interaction, whereas the subsequent fouling rate turns out to be controlled by the content of eEPS, particularly carbohydrates, which significantly correlated with viscosity and SOUR. [Display omitted] ► Effects of sludge properties on SFDM filtration characteristics were investigated. ► Large particles favor fast formation of fresh SFDMs with low filtration resistance. ► SFDM formation was dominated by permeate drag force and hydrophobic interaction. ► The content of eEPS, particularly carbohydrate, correlated with viscosity and SOUR. ► Initial fouling rate of SFDMs was mechanistically controlled by eEPS carbohydrate.