Characterization of seawater reverse osmosis fouled membranes from large scale commercial desalination plant

2019 ◽  
Author(s):  
Chem Int

The objective of this work is to study the ageing state of a used reverse osmosis (RO) membrane taken in Algeria from the Benisaf Water Company seawater desalination unit. The study consists of an autopsy procedure used to perform a chain of analyses on a membrane sheet. Wear of the membrane is characterized by a degradation of its performance due to a significant increase in hydraulic permeability (25%) and pressure drop as well as a decrease in salt retention (10% to 30%). In most cases the effects of ageing are little or poorly known at the local level and global measurements such as (flux, transmembrane pressure, permeate flow, retention rate, etc.) do not allow characterization. Therefore, a used RO (reverse osmosis) membrane was selected at the site to perform the membrane autopsy tests. These tests make it possible to analyze and identify the cause as well as to understand the links between performance degradation observed at the macroscopic scale and at the scale at which ageing takes place. External and internal visual observations allow seeing the state of degradation. Microscopic analysis of the used membranes surface shows the importance of fouling. In addition, quantification and identification analyses determine a high fouling rate in the used membrane whose foulants is of inorganic and organic nature. Moreover, the analyses proved the presence of a biofilm composed of protein.

2019 ◽  
Author(s):  
Chem Int

The objective of this work is to study the ageing state of a used reverse osmosis (RO) membrane taken in Algeria from the Benisaf Water Company seawater desalination unit. The study consists of an autopsy procedure used to perform a chain of analyses on a membrane sheet. Wear of the membrane is characterized by a degradation of its performance due to a significant increase in hydraulic permeability (25%) and pressure drop as well as a decrease in salt retention (10% to 30%). In most cases the effects of ageing are little or poorly known at the local level and global measurements such as (flux, transmembrane pressure, permeate flow, retention rate, etc.) do not allow characterization. Therefore, a used RO (reverse osmosis) membrane was selected at the site to perform the membrane autopsy tests. These tests make it possible to analyze and identify the cause as well as to understand the links between performance degradation observed at the macroscopic scale and at the scale at which ageing takes place. External and internal visual observations allow seeing the state of degradation. Microscopic analysis of the used membranes surface shows the importance of fouling. In addition, quantification and identification analyses determine a high fouling rate in the used membrane whose foulants is of inorganic and organic nature. Moreover, the analyses proved the presence of a biofilm composed of protein.


2013 ◽  
Vol 51 (7-9) ◽  
pp. 1855-1860 ◽  
Author(s):  
Mohamed O. Saeed ◽  
W.L. Teng ◽  
Ibrahim A. Al-Tisan ◽  
Mohammed A. Namazi

1975 ◽  
Author(s):  
A. P. Ball ◽  
J. Fenton ◽  
D. L. Aronson ◽  
R. B. Franza ◽  
A. M. Young

Considerable quantities of the non-thrombin portions of human prothrombin (II) have become available as a byproduct of the large-scale production of human thrombin (Biochim. Biophys. Acta 229, 26). Components not adsorbed on CG-50 are further purified by DEAE-cellulose chromatography and gel filtration, yielding the NH2-terminal fragment (F1) and the inner fragment (F2) which are homogeneous by SDS gel electrophoresis. SDS gel electrophoresis of reduced F1 indicates variable amounts of a two-chain derivative, F1’, with one chain migrating just ahead of F1 and one just ahead of the thrombin A-chain. The F1 → F1’ conversion is catalyzed by thrombin with the creation of a new MH2-terminal threonine. Ultracentrifugal patterns of human F1 and F2 closely resemble those of the bovine fragments. NH2-terminal residues were found to be alanine (± threonine) for F1 and serine for F2. Minor deviations from the reported amino acid compositions of bovine F1 and F2 were observed, primarily in the acidic residues. Other properties include:Immunization of rabbits with F1 gave a precipitating antibody to F1 which cross-reacts with II, but native F2 does not appear to be immunogenic. 3H-F1 is rapidly cleared from the blood of rabbits (T 1/2 20 min), with a major portion detectable in the urine.


2012 ◽  
Vol 7 (4) ◽  
Author(s):  
Zanguo Peng ◽  
Zhaoxuan Zhang ◽  
Pandurangan Mohan ◽  
Kasinathan Manimaran ◽  
Dongfei Li

Membrane technology has emerged as a dominant solution to seawater desalination due to its superior advantages such as stable output water quality, lower energy consumption, ease of operation and smaller footprint. However, the design of spiral wound reverse osmosis (RO) membranes used in desalination does not allow for backwash or air scouring, thus rendering the RO membrane highly susceptible to fouling. Pretreatment for the RO system is therefore essential to ensure a long service life of the RO membranes. For waters containing suspended solids of up to 75 mg/L (such as that in the SingSpring Desalination Plant at Tuas, Singapore), conventional pretreatment methods (such as dissolved air floatation and filtration (DAFF), chemical dosing and cartridge filtration) require regular operator intervention to produce a permeate of reasonably quality. Ultrafiltration (UF) as a pretreatment for seawater desalination can offer better treated water, lower operating costs, a smaller footprint, and flexibility in dealing with poor or varying feed water quality. By improving the pretreatment permeate water quality, reducing operating costs and the footprint, capital expenses can be lowered. Greater stability is also achieved during times of poor or variable feed water conditions (such as periods of algalbloom). A pilot study was conducted at SingSpring to track the performance of Hyflux's Kristal® 2000 hollow fiber UF membranes as pretreatment for the seawater reverse osmosis (SWRO) system. The results of the pilot study will enable the design of future large-scale UF-SWRO membrane projects for seawater desalination.


2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Aipeng Jiang ◽  
Qiang Ding ◽  
Jian Wang ◽  
Shu Jiangzhou ◽  
Wen Cheng ◽  
...  

Reverse osmosis (RO) technique is one of the most efficient ways for seawater desalination to solve the shortage of freshwater. For prediction and analysis of the performance of seawater reverse osmosis (SWRO) process, an accurate and detailed model based on the solution-diffusion and mass transfer theory is established. Since the accurate formulation of the model includes many differential equations and strong nonlinear equations (differential and algebraic equations, DAEs), to solve the problem efficiently, the simultaneous method through orthogonal collocation on finite elements and large scale solver were used to obtain the solutions. The model was fully discretized into NLP (nonlinear programming) with large scale variables and equations, and then the NLP was solved by large scale solver of IPOPT. Validation of the formulated model and solution method is verified by case study on a SWRO plant. Then simulation and analysis are carried out to demonstrate the performance of reverse osmosis process; operational conditions such as feed pressure and feed flow rate as well as feed temperature are also analyzed. This work is of significant meaning for the detailed understanding of RO process and future energy saving through operational optimization.


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