Effect of coagulation and PAC pretreatment on the fouling of MF and UF

2010 ◽  
Vol 5 (2) ◽  
Author(s):  
L. Nie ◽  
H. Q. Chu ◽  
B. Z. Dong ◽  
Z. Liu
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Pore Size ◽  
Active Carbon ◽  
Water Samples ◽  
Total Organic Matter ◽  
Flux Decline ◽  
Uf Membranes ◽  
Powdered Active Carbon

The water samples were fractionated by PES ultrafiltration (UF) membranes with molecular weight cutoffs (MWCOs) of 10kDa□30kDa and PVDF UF membrane with MWCOs of 100kDa, and these permeates were filtrated by PVDF UF membrane with MWCOs of 150kDa and CA microfiltration (MF) membrane with a 0.1μm pore size, as to investigate influence of nature organic matter (NOM) with different MWCOs on flux. The results demonstrated that NOM larger than 30kDa accounting for 15% of total organic matter resulted in 86% of flux decline for MF and 54% for UF, respectively. It was shown that coagulation removed the NOM larger than 100kDa that resulted in over 40% of flux decline. As a result, in spite of removing only 10% of NOM, coagulation enhanced flux substantially. Powdered active carbon (PAC) removed NOM smaller than 30kDa that showed little contribution to flux decline. Therefore, PAC removed 76% of NOM but showed little contribution to enhance flux. It can be concluded that the effect of pretreatment on enhancing flux can not be depended on amounts of NOM removed but on its contribution to flux decline.

scholarly journals Characterization of Natural Organic Matter in Conventional Water Treatment Processes and Evaluation of THM Formation with Chlorine

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Kadir Özdemır
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Water Samples ◽  
Molecular Size ◽  
Apparent Molecular Weight ◽  
Yield Coefficient ◽  
Raw Water ◽  
Treatment Processes ◽  
Uf Membranes

This study investigates the fractions of natural organic matter (NOM) and trihalomethane (THM) formation after chlorination in samples of raw water and the outputs from ozonation, coagulation-flocculation, and conventional filtration treatment units. All the water samples are passed through various ultrafiltration (UF) membranes. UF membranes with different molecular size ranges based on apparent molecular weight (AMW), such as 1000, 3000, 10,000, and 30,000 Daltons (Da), are commonly used. The NOM fraction with AMW < 1000 Da (1 K) is the dominant fraction within all the fractionated water samples. Its maximum percentage is 85.86% after the filtration process and the minimum percentage is 65.01% in raw water samples. The total THM (TTHM) yield coefficients range from 22.5 to 42 μg-TTHM/mg-DOC in all fractionated samples, which is related to their specific ultraviolet Absorbance (SUVA) levels. As the molecular weight of the fractions decreased, the TTHM yield coefficients increased. The NOM fractions with AMW values less than 1 K had lower SUVA values (<3 L/mg·m) for all treatment stages and also they had higher yield of TTHM per unit of DOC. The NOM fraction with AMW < 1 K for chlorinated raw water samples has the highest yield coefficient (42 μg-TTHM/mg-DOC).

Membrane filtration of wastewater effluents for reuse: effluent organic matter rejection and fouling

2001 ◽  
Vol 43 (10) ◽  
pp. 225-232 ◽  
Author(s):  
C. Jarusutthirak ◽  
G. Amy
Keyword(s):  
Organic Matter ◽  
Membrane Filtration ◽  
Treated Wastewater ◽  
High Concentration ◽  
Effluent Organic Matter ◽  
Dead End ◽  
Flux Decline ◽  
Uf Membranes ◽  
Stirred Cell ◽  
Filtration Unit

The reuse of treated wastewater to augment natural drinking water supplies is receiving serious consideration. Treatment of secondary and tertiary effluent by membrane filtration was investigated by assessing nanofiltration (NF) membrane and ultrafiltration (UF) membranes in bench-scale experiments. It was found that secondary and tertiary effluent contained high concentration of effluent organic matter (EfOM), contributing EfOM-related fouling. Flux decline and EfOM rejection tests were evaluated, using a dead-end stirred cell filtration unit. Surface charge and molecular weight cut-off (MWCO) of membranes were significant factors in membrane performance including permeability and EfOM-rejection.

scholarly journals Effects of mass retention of dissolved organic matter and membrane pore size on membrane fouling and flux decline

2009 ◽  
Vol 43 (2) ◽  
pp. 389-394 ◽  
Author(s):  
Cheng-Fang Lin ◽  
Angela Yu-Chen Lin ◽  
Panchangam Sri Chandana ◽  
Chao-Yuan Tsai
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Pore Size ◽  
Membrane Fouling ◽  
Membrane Pore ◽  
Flux Decline ◽  
Membrane Pore Size

Identification and control of fouling of low-pressure (MF and UF) membranes by drinking-water natural organic matter

2003 ◽  
Vol 3 (5-6) ◽  
pp. 217-222 ◽  
Author(s):  
N. Lee ◽  
G. Amy ◽  
H. Habarou ◽  
J.C. Schrotter
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Membrane Filtration ◽  
Gel Formation ◽  
Flux Decline ◽  
Organic Fouling ◽  
Pore Blockage ◽  
Uf Membranes ◽  
And Control ◽  
Filtration Flux

Natural organic matter (NOM) is responsible for organic fouling during membrane filtration. Flux decline can be affected by the characteristics of the NOM and its interaction with membranes and their associated properties. The results showed that serious flux decline observed for MF membranes may be caused by pore blockage associated with large (macromolecular) hydrophilic molecules. In the case of UF membranes, flux decline may be caused by sequential or simultaneous processes such as cake/gel formation with large (macromolecular) molecules and pore blockage with relatively smaller molecules during filtration. The flux decline tests with representative macromolecules showed that fouling was affected more by the physical characteristics (e.g. size and structure (shape)) of foulants than the characteristics (e.g. hydrophilicity) of foulants.

The removal of disinfection by-product precursors from water with ceramic membranes

2010 ◽  
Vol 62 (3) ◽  
pp. 547-555 ◽  
Author(s):  
B. I. Harman ◽  
H. Koseoglu ◽  
N. O. Yigit ◽  
E. Sayilgan ◽  
M. Beyhan ◽  
...  
Keyword(s):  
Drinking Water ◽  
Organic Matter ◽  
Pore Size ◽  
Ceramic Membrane ◽  
Uv Absorbance ◽  
Raw Water ◽  
Permeate Flux ◽  
Average Pore ◽  
Model Solutions ◽  
Uf Membranes

The main objective of this work was to investigate the effectiveness of ceramic ultrafiltration (UF) membranes with different pore sizes in removing natural organic matter (NOM) from model solutions and drinking water sources. A lab-scale, cross-flow ceramic membrane test unit was used in all experiments. Two different single-channel tubular ceramic membrane modules were tested with average pore sizes of 4 and 10 nm. The impacts of membrane pore size and pressure on permeate flux and the removals of UV280 nm absorbance, specific UV absorbance (SUVA280 nm), and dissolved organic carbon (DOC) were determined. Prior to experiments with model solutions and raw waters, clean water flux tests were conducted. UV280 absorbance reductions ranged between 63 and 83% for all pressures and membranes tested in the raw water. More than 90% of UV280 absorbance reduction was consistently achieved with both membranes in the model NOM solutions. Such high UV absorbance reductions are advantageous due to the fact that UV absorbing sites of NOM are known to be one of the major precursors to disinfection by-products (DBP) such as trihalomethanes and haloacetic acids. For both UF membranes, the ranges of DOC removals in the raw water and model NOM solutions were 55–73% and 79–91%, respectively. SUVA280 value of the raw water decreased from 2 to about 1.5 L/mg-m by both membranes. For the model solutions, SUVA280 values were consistently reduced to ≤1 L/mg-m levels after membrane treatment. As the SUVA280 value of the NOM source increased, the extent of SUVA280 reduction and DOC removal by the tested ceramic UF membranes also increased. The results overall indicated that ceramic UF membranes, especially the one with 4 nm average pore size, appear to be effective in removing organic matter and DBP precursors from drinking water sources with relatively high and sustainable permeate flux values.

Novel methods for characterizing algogenic organic matter and associated nanofiltration membrane fouling

2003 ◽  
Vol 3 (5-6) ◽  
pp. 165-174 ◽  
Author(s):  
N. Her ◽  
G. Amy ◽  
J. Yoon ◽  
M. Song
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Membrane Fouling ◽  
Operating Conditions ◽  
Size Exclusion ◽  
Membrane Properties ◽  
Feed Water ◽  
Significant Heterogeneity ◽  
Visible Absorption ◽  
Flux Decline

Algogenic organic matter (AOM) has been extracted from blue-green algae (cyanobacteria) by various means and analyzed by UV absorbance scanning, HPSEC-UV-fluorescence-DOC, FTIR, and fluorescence excitation emission matrix (EEM). AOM extracted in water as a solvent showed a high hydrophilic fraction (57.3%) with a low SUVA (1.0 L/m-mg). The molecular weight (MW) distribution showed a significant heterogeneity (high value of polydispersivity) and high protein content (as indicated by specific fluorescence). A significant amount of proteinaceous components such as mycosporine-like amino acids (MAAs, UV-screening components) and phycobilins (light-harvesting pigment) was detected by UV/visible absorption. The confirmation of proteins was proven by FTIR (at 1,661 cm-1 and 1,552 cm-1) and EEM spectra (EX: 278-282 nm and EM: 304-353 nm). A bench-scale cross-flow unit, employing a flat-sheet membrane specimen, was used to examine nanofiltration (NF) membrane fouling and removal of natural organic matter (NOM) derived from different blends of Suwannee River humic acid (SRHA) and AOM. The flux decline and organic matter rejection as a function of delivered DOC showed significantly different results depending on the organic matter composition of samples even though the test conditions were the same (organic matter concentration, pH, temperature, inorganic salt composition and concentration, and recovery). A higher flux decline was observed with increasing proportions of AOM. Organic matter rejections also decreased with higher AOM contributions to the samples, indicating that lower MW AOM components were not well rejected by the NF 200 membrane having a 360 dalton molecular weight cutoff (MWCO). However, SRHA that shows a relatively high MW (5,000-1,000 daltons) and high SUVA (7.4 L/m-mg) was preferentially rejected through electrostatic repulsion/size exclusion by the NF 200 membrane, having a high negative charge (zeta potential: -15.6 mV), low MWCO, and relatively low hydrophobicity. Even though the DOC concentration of feed water is a decisive factor for membrane fouling along with membrane properties and operating conditions, the characteristics of organic matter are more influential in fouling potential. Protein-like and polysaccharide-like substances were found as major foulants by FTIR.

Research on Characteristics Recognition of Organic Matter in Yellow River Reservoir Water

2011 ◽  
Vol 374-377 ◽  
pp. 987-990
Author(s):  
Jian Guang Liu ◽  
Meng Meng Feng ◽  
Yan Hao Zhang ◽  
Kai Li ◽  
Hui Liu
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Water Samples ◽  
Yellow River ◽  
Raw Water ◽  
Reservoir Water ◽  
River Reservoir ◽  
Determination Methods ◽  
River Reservoirs ◽  
Different Molecular Weight

Six water samples from different Yellow River reservoirs in Shandong were selected. The molecular weight distribution and type of organic matter were determined by using ultrafiltration, adsorption experiments and active bio-sand determination methods. The results show that the proportions of TOC and UV254Subscript text in different molecular weight intervals and the type of organic matter are different. But the proportion of adsorbable dissolved organic matter is the largest, which is more than 80%.In addition, the proportion of biodegradable organic matter (BDOC) is little, so the biodegradability of the raw water is not high.

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