Identification of sustainable flux in the process of using flat-sheet membrane for simultaneous thickening and digestion of waste activated sludge

Wu, Zhichao; Wang, Xinhua; Wang, Zhiwei; Du, Xingzhi

doi:10.1016/j.jhazmat.2008.06.020

Cited by 18 publications

(6 citation statements)

References 34 publications

(42 reference statements)

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“…3a and b) due to the channel clogging ("pre-clogged" state), with values noticeably depressed (by 25-50%) for the duplicated trial ("post-clogged" state). The trend is similar to that reported by Wu et al (2009) in their studies of an FS iMBR for membrane-based simultaneous sludge thickening and aerobic digestion of activated sludge. These authors reported thickening of the sludge from 5-35 g L -1 MLSS to decrease the operational flux from 30 to 10 LMH.…”

Section: Low Mlss Trialsupporting

confidence: 89%

“…Whilst it is generally recognised that higher mixed liquor suspended solids (MLSS) concentrations tend to depress foulant levels, manifested as soluble microbial product (SMP), such observations have tended to be limited to moderate MLSS concentrations of up to 25 g L -1 (Yeom et al, 2005;Schwarz et al, 2006). A body of work specifically on simultaneous aerobic digestion and thickening of WAS (Wang et al, 2008(Wang et al, , 2009Wu et al, 2009) was focused largely on the soluble foulant levels, manifested as soluble microbial product (SMP) and colloidal and/or soluble chemical oxygen demand (sCOD), and bulk sludge quality parameters such as viscosity and capillary suction time (CST). Results showed SMP and sCOD to significantly influence membrane fouling.…”

Section: Introductionmentioning

confidence: 99%

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Biological treatment and thickening with a hollow fibre membrane bioreactor

et al. 2014

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Aerobic operation of an immersed hollow fibre membrane bioreactor, treating municipal wastewater supplemented with molasses solution, has been studied across mixed liquor suspended solids (MLSS) concentrations between 8 and 32 g L(-1), the higher concentrations being normally associated with thickening operations. Only a marginal loss in membrane permeability was noted between 8 and 18 g L(-1) when operation was conducted without clogging. The sustainable operational flux attainable above 18 g L(-1) was highly dependent upon both the MLSS concentration and the state of the membrane. A temperature-corrected flux of 28 L m(-2) h(-1) (LMH) was sustained for 18 h at an MLSS of 8 g L(-1) using membranes close to initial their virgin-state permeability. This value decreased to around 14 LMH at 20 g L(-1) and 5 LMH at 32 g L(-1) MLSS for an aged membrane whose permeability had been recovered following clogging. Below the threshold flux operation without significant clogging was possible, such that the membrane permeability could be recovered with a chemically enhanced backflush (CEB). Above this flux clogging took place at a rate of around 7-14 g solids per m(2) membrane per m(3) permeate volume passed irrespective of the MLSS concentration. The permeability of the unclogged membrane was depressed and could not be recovered using a standard CEB, indicative of irrecoverable pore clogging. The outcomes corroborated previously reported observations concerning the deleterious long-term impacts of clogging, and confirmed the critical importance of operation at a sustainable flux value.

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Section: Low Mlss Trialsupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Biological treatment and thickening with a hollow fibre membrane bioreactor

et al. 2014

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“…The effect of activated sludge mixed liquor (mixed liquor suspended solids (MLSS)) concentration on membrane fouling can be highlighted as an example. Although one group of researchers did not observe a correlation between MLSS concentration (3.6–21.1 g/L) and membrane fouling, another group reported that MLSS concentration (4.6–19 g/L) had an important effect on membrane fouling . Similar contradictions have been reported for other parameters.…”

Section: Introductionmentioning

confidence: 69%

Correlation of Filtration Resistance with Microbial Polymeric Substances Extracted from Membranes in a Submerged Membrane Bioreactor

Kayaalp

Kinaci

Dizge

et al. 2014

CLEAN Soil Air Water

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The current understanding of membrane fouling in submerged membrane bioreactors is still insufficient. Therefore, the role of microbial polymeric substances in membrane fouling mechanisms in a submerged membrane bioreactor was systematically investigated in this study. Microbial polymeric foulants accumulated on the membrane surface and in its pores. The foulants were then extracted in three steps, without deforming the membrane structure. Moreover, filtration resistances were determined by the resistance in series model. A strong functional relationship was observed between total polymeric substances accumulated in the membrane and their fouling resistances. The greatest accumulation of polymeric substances occurred in cake layers formed on the membrane surface. Correspondingly, the greatest fouling resistance resulted from the cake layer. The results indicated that more protein accumulated on the membrane surface than carbohydrates because the proteins were stickier. Regarding the analysis of microbial polymeric substances, it was observed that the filtration with a 0.45 mm pore size filter did not capture all of the polymeric substances that took part in membrane fouling.

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“…A water-level sensor was used for maintaining a constant water level in the reactor over the experimental period. The operation of the MSTD process has been reported in our previous studies [18,19]. When the MLSS concentrations in the reactor reached approximately 30 g/L, the thickened sludge was drained out while the influent activated sludge and the permeate flow were stopped.…”

Section: Experimental Setup and Operationmentioning

confidence: 98%

Identification of sustainable flux in the process of using flat-sheet membrane for simultaneous thickening and digestion of waste activated sludge

Cited by 18 publications

References 34 publications

Biological treatment and thickening with a hollow fibre membrane bioreactor

Biological treatment and thickening with a hollow fibre membrane bioreactor

Correlation of Filtration Resistance with Microbial Polymeric Substances Extracted from Membranes in a Submerged Membrane Bioreactor

Membrane fouling mechanisms in the process of using flat-sheet membrane for simultaneous thickening and digestion of activated sludge

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