Enhanced Separation Performance of PVDF/PVP-g-MMT Nanocomposite Ultrafiltration Membrane Based on the NVP-Grafted Polymerization Modification of Montmorillonite (MMT)

Effects of clay on fouling due to organic substances and clay were evaluated by model fouling materials and kaolin. Model fouling materials selected were protein, polysaccharide, fulvic acid, humic acid and algogenic matter (EOM:ectracellular organic matter, microbial decomposition products) and kaolin was selected as the clay material. Polysulfone membrane (MWCO(Molecular Weight Cut-Off) 10,000, 50,000 and 200,000) was used as an ultrafiltration membrane. In particular, the flux measurement of solutions containing algogenic matter used an ultrafiltration membrane of MWCO 50,000. The flux of protein and polysaccharide with coexistence of kaolin increased in the case of the ratio of MW/MWCO being greater than one, but did not increase in the case of the MW/MWCO ratio being below one. In contrast, the flux of fulvic acid and humic acid with coextence of kaolin decreased regardless of the ratio of MW/MWCO. The addition of dispersion agent and coagulant in the organic substances and kaolin mixture solution changed the size distribution of kaolin, and resulted in a change of the flux. EOM and microbial decomposition products decreased with the increase of the fraction of organic matter having molecular weight more than MWCO of membrane. The flux of the algogenic organic matter with coexistence of kaolin decreased with the increase of the amount of kaolin. It was suggested that the decline of the flux with coexistence of kaolin was due to the change of the resistance of the kaolin cake layer corresponding to the change in kaolin size distribution with charge.

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Biological sulfate removal in an acidogenic bioreactor with an ultrafiltration membrane system

Water Science & Technology ◽

10.2166/wst.1998.0709 ◽

1998 ◽

Vol 38 (4-5) ◽

pp. 513-520 ◽

Cited By ~ 2

Author(s):

O. Mizuno ◽

H. Takagi ◽

T. Noike

Keyword(s):

Sulfate Reduction ◽

Membrane Filtration ◽

Membrane Bioreactor ◽

Volatile Fatty Acids ◽

Membrane System ◽

Organic Substrate ◽

Ultrafiltration Membrane ◽

Sulfate Concentration ◽

Sulfate Removal ◽

Chemostat Reactor

The biological sulfate removal in the acidogenic bioreactor with an ultrafiltration membrane system was investigated at 35°C. Sucrose was used as the sole organic substrate. The sulfate concentration in the substrate ranged from 0 to 600mgS·1−1. The chemostat reactor was operated to compare with the membrane bioreactor. The fouling phenomenon caused by FeS precipitate was observed at higher concentration of sulfate. However, it was possible to continuously operate the membrane bioreactor by cleaning the membrane. The efficiency of sulfate removal by sulfate reduction reached about 100% in the membrane bioreactor, and 55 to 87% of sulfide was removed from the permeate by the membrane filtration. The composition of the metabolite was remarkably changed by the change in sulfate concentration. When the sulfate concentration increased, acetate and 2-proponol significantly increased while n-butyrate and 3-pentanol decreased. The sulfate-reducing bacteria play the role as acetogenic bacteria consuming volatile fatty acids and alcohols as electron donors under sulfate-rich conditions. The results show that the acidogenesis and sulfate reduction simultaneously proceed in the membrane bioreactor.

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Field testing CFD-based predictions of storage chamber gross solids separation efficiency

Water Science & Technology ◽

10.2166/wst.1999.0467 ◽

1999 ◽

Vol 39 (9) ◽

pp. 161-168 ◽

Cited By ~ 8

Author(s):

Virginia R. Stovin ◽

Adrian J. Saul ◽

Andrew Drinkwater ◽

Ian Clifforde

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Settling Velocity ◽

Separation Efficiency ◽

Flow Patterns ◽

Total Efficiency ◽

Separation Performance ◽

Storage Chamber ◽

Solids Separation ◽

Simulated Flow

The use of computational fluid dynamics-based techniques for predicting the gross solids and finely suspended solids separation performance of structures within urban drainage systems is becoming well established. This paper compares the result of simulated flow patterns and gross solids separation predictions with field measurements made in a full size storage chamber. The gross solids retention efficiency was measured for six different storage chambers in the field and simulations of these chambers were undertaken using the Fluent computational fluid dynamics software. Differences between the observed and simulated flow patterns are discussed. The simulated flow fields were used to estimate chamber efficiency using particle tracking. Efficiency results are presented as efficiency cusps, with efficiency plotted as a function of settling velocity. The cusp represents a range of efficiency values, and approaches to the estimation of an overall efficiency value from these cusps are briefly discussed. Estimates of total efficiency based on the observed settling velocity distribution differed from the measured values by an average of ±17%. However, estimates of steady flow efficiency were consistently higher than the observed values. The simulated efficiencies agreed with the field observations in identifying the most efficient configuration.

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