Influence of COD:N ratio on sludge properties and their role in membrane fouling of a submerged membrane bioreactor

http://www.sciencedirect.com/science/article/pii/S004313541530378X

Hao, L., Liss, S. N., & Liao, B. Q. (2015). Influence of COD:N ratio on sludge properties and their role in membrane fouling of a submerged membrane bioreactor. Water Research, 89, 132–141. http://doi.org/10.1016/j.watres.2015.11.052

Abstract

The effect of COD:N ratio on sludge properties and their role in membrane fouling were examined using a well-controlled aerobic membrane bioreactor receiving a synthetic high strength wastewater containing glucose. Membrane performance was improved with an increase in the COD/N ratio (100:5–100:1.8) (i.e. reduced N dosage). Surface analysis of sludge by X-ray photoelectron spectroscopy (XPS) indicates significant differences in surface concentrations of elements C, O and N that were observed under different COD/N ratios, implying changes in the composition of extracellular polymeric substances (EPS). Fourier transform-infrared spectroscopy (FTIR) revealed a unique characteristic peak (CO bonds) at 1735 cm−1 under nitrogen limitation conditions. Total EPS decreased with an increase in COD/N ratio, corresponding to a decrease in the proteins (PN) to carbohydrates (CH) ratio in EPS. There were no significant differences in the total soluble microbial products (SMPs) but the ratio of PN/CH in SMPs decreased with an increase in COD/N ratios. The results suggest that EPS and SMP composition and the presence of a small quantity of filamentous microorganisms played an important role in controlling membrane fouling.

Comment

C/N비가 올라가면 막오염이 저감된다는 논문.

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COD/N비가 EPS와 SMP에 미치는 영향

Influence of COD:N ratio on sludge properties and their role in membrane fouling of a submerged membrane bioreactor
L. Hao, S.N. Liss, B.Q. Liao

http://www.sciencedirect.com/science/article/pii/S004313541530378X

Abstract
The effect of COD:N ratio on sludge properties and their role in membrane fouling were examined using a well-controlled aerobic membrane bioreactor receiving a synthetic high strength wastewater containing glucose. Membrane performance was improved with an increase in the COD/N ratio (100:5–100:1.8) (i.e. reduced N dosage). Surface analysis of sludge by X-ray photoelectron spectroscopy (XPS) indicates significant differences in surface concentrations of elements C, O and N that were observed under different COD/N ratios, implying changes in the composition of extracellular polymeric substances (EPS). Fourier transform-infrared spectroscopy (FTIR) revealed a unique characteristic peak (Cdouble bond; length as m-dashO bonds) at 1735 cm−1 under nitrogen limitation conditions. Total EPS decreased with an increase in COD/N ratio, corresponding to a decrease in the proteins (PN) to carbohydrates (CH) ratio in EPS. There were no significant differences in the total soluble microbial products (SMPs) but the ratio of PN/CH in SMPs decreased with an increase in COD/N ratios. The results suggest that EPS and SMP composition and the presence of a small quantity of filamentous microorganisms played an important role in controlling membrane fouling.

- 고농도 합성하수 이용
- C/N비가 증가하면 Membrane performance는 증가 (100:5-100:1.8)
- CN는 EPS의 성상을 변화시킴
- 질소의 제한은 EPS 생성을 감소시킴  단백질 감소 때문
- SMP 양은 크게 다르지 않음. 단 Protein/carbohydrate는 감소

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Oasys사 TFC FO막 성능 평가 논문

Characterization and Performance Relationships for a Commercial Thin Film Composite Membrane in Forward Osmosis Desalination and Pressure Retarded Osmosis

Jason T. Arena†, Seetha S. Manickam†, Kevin K. Reimund†, Pavel Brodskiy‡, and Jeffrey R. McCutcheon*†
Ind. Eng. Chem. Res., 2015, 54 (45), pp 11393–11403
http://pubs.acs.org/doi/10.1021/acs.iecr.5b02309

Abstract

This paper presents performance data for an early generation thin film composite membrane from Oasys Water. These tests sought to measure the membrane’s basic chemical and morphological characteristics with additional testing to measure benchmark performance in both seawater-riverwater pressure retarded osmosis and forward osmosis desalination using the ammonia-carbon dioxide draw solution. In pressure retarded osmosis the membrane exhibited compaction which increased structural parameter. While in forward osmosis desalination, substantial cation flux was observed using the ammonia-carbon dioxide draw solution.

Main results

water permeance 4.25 ± 0.04 L·m–2·h–1·bar–1
2000 ppm intrinsic sodium chloride rejection (%) 99.2 ± 0.2%
sodium chloride permeability 0.38 ± 0.11 L·m–2·h–1
effective structural parameter 483 ± 79 μm

Comments

Oasys사의 TFC FO 막 성능테스트, FO와 PRO 모드에서. 표준 조건을 사용해서 성능 비교하기에 좋은 논문

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FO 유도용질 논문 (carboxyethyl amine sodium salts)

Novel carboxyethyl amine sodium salts as draw solutes with superior forward osmosis performance

Qingwu Long, Yan Wang
http://onlinelibrary.wiley.com/doi/10.1002/aic.15126/full

Abstract

A series of carboxyethyl amine sodium salts (CASSs) with different carboxyl group numbers are synthesized as draw solutes for forward osmosis (FO) application. Their chemical structures are examined by 1HNMR and HRMS. FO performances are investigated and compared in terms of different physicochemical properties. The effects of the CASS concentration on the osmotic pressure and viscosity of the draw solutions, as well as the resulted FO performance are also systematically investigated. A high water flux of 23.07 LMH and an acceptable reverse salt flux of 0.75 gMH can be achieved with 0.5 g mL−1 triethylenetetramine hexapropionic acid sodium (TTHP-Na) draw solution under PRO mode, which is superior to most other draw solutes reported in previous literatures. TTHP-Na draw solution is further evaluated to recycle the Congo red solution via FO process to examine its applicability for waste water treatment. © 2015 American Institute of Chemical Engineers AIChE J, 2015

Comments

FO 유도용질 관련 논문. carboxyethyl amine sodium salts. PRO 조건에서 실험.

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FO-MBR의 막오염에 대한 논문

Comparison of biofouling mechanisms between cellulose triacetate (CTA) and thin-film composite (TFC) polyamide forward osmosis membranes in osmotic membrane bioreactors

Xinhua Wang, Yanxiao Zhao, Bo Yuan, Zhiwei Wang, Xiufen Li, , , Yueping Ren
(Bioresource Technology Volume 202, February 2016, Pages 50–58)
http://www.sciencedirect.com/science/article/pii/S096085241501620X

Abstract

There are two types of popular forward osmosis (FO) membrane materials applied for researches on FO process, cellulose triacetate (CTA) and thin film composite (TFC) polyamide. However, performance and fouling mechanisms of commercial TFC FO membrane in osmotic membrane bioreactors (OMBRs) are still unknown. In current study, its biofouling behaviors in OMBRs were investigated and further compared to the CTA FO membrane. The results indicated that β-d-glucopyranose polysaccharides and microorganisms accounted for approximately 77% of total biovolume on the CTA FO membrane while β-d-glucopyranose polysaccharides (biovolume ratio of 81.1%) were the only dominant biofoulants on the TFC FO membrane. The analyses on the biofouling structure implied that a tighter biofouling layer with a larger biovolume was formed on the CTA FO membrane. The differences in biofouling behaviors including biofoulants composition and biofouling structure between CTA and TFC FO membranes were attributed to different membrane surface properties.

Keywords

Osmotic membrane bioreactor; Cellulose triacetate; Thin-film composite; Forward osmosis; Biofouling

Comments

FO를 이용한 MBR에서 biofouling에서 일어나는 현상에 대한 연구가 많이 진행되는 듯. 본 논문에서는 CTA 막과 TFC 막을 비교. 두 막의 표면 특성이 달라서 막오염 현상이 다르게 일어남 (TFC가 더 빨리 안좋아짐). 처리수의 수질은 크게 차이 나지 않음.

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Graphene와 Silver nanoparticle을 이용해 FO TFC 막 modification

In Situ Silver Decoration on Graphene Oxide-Treated Thin Film Composite Forward Osmosis Membranes: Biocidal Properties and Regeneration Potential

Adel Soroush†, Wen Ma†, Myriam Cyr†, Md. Saifur Rahaman*†, Bahareh Asadishad‡, and Nathalie Tufenkji‡
† Department of Building, Civil and Environmental Engineering, Concordia University, Montreal, Quebec, Canada H3G 1M8
‡ Department of Chemical Engineering, McGill University, Montreal, Quebec, Canada H3A 0C5
(Environ. Sci. Technol. Lett., Article ASAP)
http://pubs.acs.org/doi/full/10.1021/acs.estlett.5b00304

Abstract

The surfaces of thin film composite (TFC) forward osmosis (FO) membranes were modified by in situ formation of silver nanoparticles (AgNPs) in the presence and absence of graphene oxide (GO) nanosheets to impart biocidal properties to the membranes. The abundance of oxygen-containing functional groups in GO makes it suitable for anchoring Ag+ ions and governing the size, shape, and distribution of AgNPs. The presence of GO resulted in the formation of smaller and uniformly distributed AgNPs as well as increased silver loading, higher stability, and enhanced ion release control. Membranes modified by both GO and Ag exhibited improved (98%) bacterial inactivation when compared to that of only Ag-modified (80%) or GO-modified membranes (50%). After release of Ag ion from GO-Ag-modified membranes for 7 days, AgNP regeneration was conducted in a manner identical to the in situ Ag formation procedure. After regeneration, the membrane regained nearly all of its antibacterial properties and 75% of its initial silver loading.

Comments

기존 HTI의 PA-TFC FO 멤브레인에 Graphene와 Silver nanoparticle을 이용해 modify한 후 미생물 제거 능력이 향상되었다는 논문.

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FO-MBR의 막오염에 대한 논문

Comparison of biofouling mechanisms between cellulose triacetate (CTA) and thin-film composite (TFC) polyamide forward osmosis membranes in osmotic membrane bioreactors

Xinhua Wang, Yanxiao Zhao, Bo Yuan, Zhiwei Wang, Xiufen Li, , , Yueping Ren
(Bioresource Technology Volume 202, February 2016, Pages 50–58)
http://www.sciencedirect.com/science/article/pii/S096085241501620X

Abstract

There are two types of popular forward osmosis (FO) membrane materials applied for researches on FO process, cellulose triacetate (CTA) and thin film composite (TFC) polyamide. However, performance and fouling mechanisms of commercial TFC FO membrane in osmotic membrane bioreactors (OMBRs) are still unknown. In current study, its biofouling behaviors in OMBRs were investigated and further compared to the CTA FO membrane. The results indicated that β-d-glucopyranose polysaccharides and microorganisms accounted for approximately 77% of total biovolume on the CTA FO membrane while β-d-glucopyranose polysaccharides (biovolume ratio of 81.1%) were the only dominant biofoulants on the TFC FO membrane. The analyses on the biofouling structure implied that a tighter biofouling layer with a larger biovolume was formed on the CTA FO membrane. The differences in biofouling behaviors including biofoulants composition and biofouling structure between CTA and TFC FO membranes were attributed to different membrane surface properties.

Keywords

Osmotic membrane bioreactor; Cellulose triacetate; Thin-film composite; Forward osmosis; Biofouling

Comments

FO를 이용한 MBR에서 biofouling에서 일어나는 현상에 대한 연구가 많이 진행되는 듯. 본 논문에서는 CTA 막과 TFC 막을 비교. 두 막의 표면 특성이 달라서 막오염 현상이 다르게 일어남 (TFC가 더 빨리 안좋아짐). 처리수의 수질은 크게 차이 나지 않음.

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