Recycling of Reverse Osmosis Concentrates to the Membrane Bioreactor in the MBR-RO Process for Water Reuse: effect on mbr performances

Wastewater effluents can be treated by an integrated membrane system combining membrane bioreactor (MBR) and reverse osmosis (RO) for effective removal of micropollutants in the field of high-quality water reuse. However, discharging the RO concentrate waste stream directly into the natural environment could lead to serious problems due to the toxic components contained in the concentrates (micropollutants, salts, organic matter). A possible solution could be the recirculation of RO concentrate waste to the MBR. However, such an operation should be studied in detail since the recirculation of non-biodegradable organic matter or high concentrations of salts and micropollutants could directly or indirectly contribute to MBR membrane fouling and modification of the biodegradation activity. In this context, the work reported here focused on the recirculation of such concentrates in an MBR, paying specific attention to MBR membrane fouling. Lab-scale experiments were performed on a continuous MBR-RO treatment line with RO concentrate recirculation. The main goal was to determine the recovery of the RO unit and of the global process that maintained good process performance in terms of biodegradation and MBR fouling. The results demonstrate that the impact of the toxic flow on activated sludge depends on the recovery of the RO step but the same trends were observed regardless of the organic matter and salt contents of the concentrates: the concentration of proteins increased slightly. Size-exclusion high performance liquid chromatography (HPLC-SEC) was employed to study the effects of RO concentrate on the production of protein-like soluble microbial products (SMPs) and demonstrated a significant peak of protein-like substances corresponding to 10-100 kDa and 100-1 000 kDa molecules in the supernatant. Thus a significant increase in the propensity for sludge fouling was observed, which could be attributed to the increased quantity of protein-like substances. Finally, the effect of the concentrate on sludge activity was studied and no significant effect was observed on biodegradation, indicating that the return of the concentrate to the MBR could be a good alternative.

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Study on performance of ultrafiltration membrane-based pretreatment for application to seawater reverse osmosis desalination

Water Science & Technology ◽

10.2166/wst.2010.483 ◽

2010 ◽

Vol 62 (9) ◽

pp. 1984-1990 ◽

Cited By ~ 6

Author(s):

C. Tansakul ◽

S. Laborie ◽

C. Cabassud

Keyword(s):

Organic Matter ◽

Surface Area ◽

Membrane Fouling ◽

High Performance ◽

Size Exclusion ◽

Bet Surface Area ◽

Regenerated Cellulose ◽

Cellulose Membrane ◽

Organic Matter Removal ◽

Exclusion Chromatography

The objective of the work was to study at lab-scale the efficiency of hybrid process- coupling powdered activated carbon (PAC) adsorption or FeCl3 coagulation and UF- for marine organic matter removal. Regenerated cellulose membrane with 30 kDa and actual seawater from Mediterranean Sea were used. The coagulant was FeCl3 and adsorbents were two PAC types, with different surface area and pore size distribution. The results showed that PAC adsorption/UF performed higher efficiency in terms of organic removal than FeCl3 coagulation/UF. Organic matter removal up to 50% was obtained for a PAC dose of 200 mg/L. According to high performance size exclusion chromatography (HP-SEC) analysis, the organics removed by PAC/UF are approximately 10 kDa. Therefore, the effect of PAC adsorption was deeply evaluated in terms of UF membrane fouling rate. The fouling rate was reduced when increasing PAC dose for both PAC types, in particular when PAC with a higher BET surface area and larger fraction of micropores was used. On the other hand, the results showed that UF unit could highly reduce SDI3 from 26 to 9. The addition of PAC and FeCl3 to UF allowed a further reduction of SDI3 from 9 to 4–6.

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Evaluation of a bench-scale membrane fouling protocol to determine fouling propensities of membranes during full-scale water reuse applications

Water Science & Technology ◽

10.2166/wst.2010.416 ◽

2010 ◽

Vol 62 (5) ◽

pp. 1198-1204

Author(s):

C. L. Bellona ◽

A. Wuertle ◽

P. Xu ◽

J. E. Drewes

Keyword(s):

Organic Matter ◽

Membrane Fouling ◽

Water Reuse ◽

Membrane System ◽

Full Scale ◽

Effluent Organic Matter ◽

Bench Scale ◽

Testing Protocol ◽

Pre Treatment ◽

Wastewater Effluents

There is increasing interest in recycling wastewater effluents for augmentation of existing water supplies. The treatment of wastewater effluents by an integrated membrane system, such as microfiltration pre-treatment followed by reverse osmosis, is the industry standard for groundwater recharge or reservoir augmentation projects. Membrane fouling, especially effluent organic matter fouling, is a major challenge for water reuse applications employing high-pressure membranes. While fouling control through pre-treatment is an important aspect in membrane system design and operation, selecting low fouling membranes is an equally important aspect. Although recent research has begun to elucidate fouling mechanisms, little work has been performed to develop methods to pre-determine the effluent organic matter fouling propensities of high-pressure membranes so that low-fouling membranes can be pre-selected for reuse applications. The purpose of this study was to utilize a bench-scale testing protocol to test the relative effluent organic matter fouling propensities of commercially available NF and RO membranes when treating wastewater effluents. Bench-scale fouling test results were then compared to operational data generated during pilot- and full-scale membrane testing. Pilot- and full-scale testing using recycled water demonstrated that membranes foul at significantly different rates and that the extent of fouling could be estimated utilizing the proposed bench-scale testing protocol.

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Application of a fractionation technique for better understanding of the removal of natural organic matter by alum coagulation

Water Science & Technology Water Supply ◽

10.2166/ws.2002.0200 ◽

2002 ◽

Vol 2 (5-6) ◽

pp. 427-433 ◽

Cited By ~ 4

Author(s):

J. van Leeuwen ◽

C. Chow ◽

R. Fabris ◽

N. Withers ◽

D. Page ◽

...

Keyword(s):

Organic Matter ◽

Natural Organic Matter ◽

High Performance ◽

Relative Proportion ◽

Water Source ◽

Size Exclusion ◽

Gas Chromatography Mass Spectrometry ◽

Pyrolysis Gas ◽

Alum Treatment ◽

Hydrophobic Acids

To gain an improved understanding of the types of organic compounds that are recalcitrant to water treatment, natural organic matter (NOM) isolates from two drinking water sources (Mt. Zero and Moorabool reservoirs, Victoria, Australia) were separated into fractions of distinct chemical behaviour using resins. Four fractions were obtained from each water source and were organics absorbed to: (1) XAD-8 (very hydrophobic acids, VHA); (2) DAX-4 (slightly hydrophobic acids, SHA); (3) bound to an anion exchange resin (charged organics, CHAR); and (4) not absorbed or bound to resins (neutrals, NEUT). These fractions were then tested to determine the capacity of alum to remove them from water and to correlate this with the character of each isolate. The fractions were characterised by the application of high performance size exclusion chromatography (HPSEC), bacterial regrowth potential (BRP), trihalomethane formation potential (THMFP), pyrolysis gas-chromatography mass spectrometry (Py-GC-MS) and thermochemolysis. The highest removals of dissolved organic carbon (DOC) by alum treatment were in waters spiked with the CHAR fractions while the NEUT fractions were the most recalcitrant. The number average molecular weights (Mn) of DOC of the CHAR fractions before treatment were the highest, whilst those of the NEUT fractions were the lowest. After alum treatment, the Mn of the NEUT fractions were only slightly reduced. Results from Py-GC-MS and thermochemolysis indicate that the NEUT fractions had the highest relative proportion of saccharide derived organic material. Nonetheless, the BRP of waters spiked with the NEUT fractions differed markedly, indicating that organics recalcitrant to alum treatment can vary substantially in their chemical composition and capacity to support microbial growth.

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Characterization of size fractionated dissolved organic matter from river water and wastewater effluent using preparative high performance size exclusion chromatography

Organic Geochemistry ◽

10.1016/j.orggeochem.2016.11.003 ◽

2017 ◽

Vol 103 ◽

pp. 105-112 ◽

Cited By ~ 17

Author(s):

Kangmin Chon ◽

Kyongmi Chon ◽

Jaeweon Cho

Keyword(s):

Organic Matter ◽

Dissolved Organic Matter ◽

River Water ◽

Size Exclusion Chromatography ◽

High Performance ◽

Wastewater Effluent ◽

Size Exclusion ◽

Exclusion Chromatography ◽

Water And Wastewater

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Comparison of two treatments for the removal of selected organic micropollutants and bulk organic matter: conventional activated sludge followed by ultrafiltration versus membrane bioreactor

Water Science & Technology ◽

10.2166/wst.2011.300 ◽

2011 ◽

Vol 63 (4) ◽

pp. 733-740 ◽

Cited By ~ 26

Author(s):

E. Sahar ◽

M. Ernst ◽

M. Godehardt ◽

A. Hein ◽

J. Herr ◽

...

Keyword(s):

Organic Matter ◽

Activated Sludge ◽

Membrane Fouling ◽

Membrane Bioreactor ◽

Sewage Treatment Plant ◽

Treatment Plant ◽

Macrolide Antibiotics ◽

Organic Micropollutants ◽

Removal Rates ◽

Conventional Activated Sludge

The potential of membrane bioreactor (MBR) systems to remove organic micropollutants was investigated at different scales, operational conditions, and locations. The effluent quality of the MBR system was compared with that of a plant combining conventional activated sludge (CAS) followed by ultrafiltration (UF). The MBR and CAS-UF systems were operated and tested in parallel. An MBR pilot plant in Israel was operated for over a year at a mixed liquor suspended solids (MLSS) range of 2.8–10.6 g/L. The MBR achieved removal rates comparable to those of a CAS-UF plant at the Tel-Aviv wastewater treatment plant (WWTP) for macrolide antibiotics such as roxythromycin, clarithromycin, and erythromycin and slightly higher removal rates than the CAS-UF for sulfonamides. A laboratory scale MBR unit in Berlin – at an MLSS of 6–9 g/L – showed better removal rates for macrolide antibiotics, trimethoprim, and 5-tolyltriazole compared to the CAS process of the Ruhleben sewage treatment plant (STP) in Berlin when both were fed with identical quality raw wastewater. The Berlin CAS exhibited significantly better benzotriazole removal and slightly better sulfamethoxazole and 4-tolyltriazole removal than its MBR counterpart. Pilot MBR tests (MLSS of 12 g/L) in Aachen, Germany, showed that operating flux significantly affected the resulting membrane fouling rate, but the removal rates of dissolved organic matter and of bisphenol A were not affected.

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High-performance size exclusion chromatography with a multi-wavelength absorbance detector study on dissolved organic matter characterisation along a water distribution system

Journal of Environmental Sciences ◽

10.1016/j.jes.2015.12.011 ◽

2016 ◽

Vol 44 ◽

pp. 235-243 ◽

Cited By ~ 12

Author(s):

Huiping Huang ◽

Emma Sawade ◽

David Cook ◽

Christopher W.K. Chow ◽

Mary Drikas ◽

...

Keyword(s):

Organic Matter ◽

Dissolved Organic Matter ◽

Size Exclusion Chromatography ◽

Distribution System ◽

High Performance ◽

Water Distribution ◽

Water Distribution System ◽

Size Exclusion ◽

Exclusion Chromatography ◽

Multi Wavelength

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Characterization of dissolved organic matter from Australian and Chinese source waters by combined fractionation techniques

Water Science & Technology ◽

10.2166/wst.2011.432 ◽

2011 ◽

Vol 64 (1) ◽

pp. 171-177 ◽

Cited By ~ 3

Author(s):

Qunshan Wei ◽

Rolando Fabris ◽

Christopher W. K. Chow ◽

Changzhou Yan ◽

Dongsheng Wang ◽

...

Keyword(s):

Organic Matter ◽

Dissolved Organic Matter ◽

High Performance ◽

Size Exclusion ◽

Rapid Urbanization ◽

Molecular Weights ◽

Treatment Processes ◽

Exclusion Chromatography ◽

Urbanization In China ◽

Source Waters

The character of dissolved organic matter (DOM) in source waters from two countries (Australia and China) was investigated using an extended fractionation technique by combining resin adsorption, ultrafiltration and high performance size exclusion chromatography. There are distinctive chemical characteristics associated with DOM origins. Australian sourced DOM had higher hydrophobic acid (HoA) content and exhibited a more pronounced humic character, indicating a higher influence from allochthonous organics (decayed plant bodies from vegetated catchments). The higher content of hydrophobic base and neutral components found in Chinese DOM, may be attributed to the effects of increasing pollution caused by the rapid urbanization in China. The molecular weights (MWs) of aquatic HoA are predominantly in the moderate (e.g. 1–10 kDa) or small (e.g. <1 kDa) ranges. This suggests that aquatic HoA should not be assumed as high MW organics without experimental validation. It is also found that some of the low MW compounds in our samples were hydrophobic, which could explain the observation of low MW organic compounds being able to be removed by conventional treatment processes.

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