Monitoring of biofouling on ultrafiltration hollow fiber membranes by rapid enzyme activity assays

2012 ◽  
Vol 12 (2) ◽  
pp. 148-156
Author(s):  
C. Sun ◽  
L. Fiksdal
Keyword(s):  
Drinking Water ◽  
Enzyme Activity ◽  
Water Treatment ◽  
Hollow Fiber ◽  
Drinking Water Treatment ◽  
Operating Conditions ◽  
Peptidase Activity ◽  
Test Unit ◽  
Membrane Unit ◽  
Membrane Biofouling

The biofouling of an ultrafiltration (UF) membrane unit applied for drinking water treatment was investigated under three different operating conditions, i.e. flux 50, 60 and 70 L m−2 h−1. The biofouling was monitored by analyzing the enzyme (esterase and peptidase) activity on the sacrificed membrane fibers of a test unit installed in the same reactor as the membrane pilot module. At a given flux, a decrease of membrane permeability generally corresponded to an increase of enzyme activity. Enzyme activity could therefore be used to predict the permeability decline and potentially be used for e.g. at-line monitoring of membrane biofouling.

Pilot scale evaluation of biofiltration as an innovative pre-treatment for ultrafiltration membranes for drinking water treatment

2011 ◽  
Vol 11 (1) ◽  
pp. 23-29 ◽  
Author(s):  
P. M. Huck ◽  
S. Peldszus ◽  
C. Hallé ◽  
H. Ruiz ◽  
X. Jin ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Membrane Fouling ◽  
Drinking Water Treatment ◽  
Pilot Scale ◽  
Operating Conditions ◽  
Membrane Unit ◽  
Ozone Addition ◽  
Pre Treatment ◽  
Uf Membranes

Fouling remains one of the major constraints on the use of low pressure membranes in drinking water treatment. Work over the last few years has shown the importance of biopolymers (carbohydrates and protein-like material) as foulants for ultrafiltration (UF) membranes. The purpose of this study was to investigate at pilot scale the use of rapid biofiltration (without prior coagulation or ozone addition) as an innovative pretreatment to reduce fouling of UF membranes. The investigation was carried out on a water with a higher than average DOC and significant temperature variation. The biofilters, each operated at a hydraulic loading of 5 m/h, had empty bed contact times of 5, 10 and 15 minutes. The membrane unit was operated at a flux equivalent to 60 LMH at 20°C. The investigation confirmed the encouraging results obtained in an earlier smaller scale study with essentially the same water. Increased biofiltration contact time (i.e. increased bed depth) led to lower rates of hydraulically irreversible fouling. The initial biofiltration backwash procedure, involving air scour as is common in chemically assisted filtration, led in some cases to an increased rate of membrane fouling immediately after the backwash. An alternative backwashing strategy was developed, however the feasibility of operating with this approach over very long periods of time needs to be confirmed. To assist in full-scale implementation of this “green” and simple pretreatment, the design and operating conditions for the biofilters should be optimized for various types of waters. It is expected that biofiltration pretreatment will be of particular interest for small and/or isolated systems where a higher initial capital cost may be acceptable because of operational simplicity and reduced chemical requirements.

scholarly journals The Role of Catalytic Ozonation Processes on the Elimination of DBPs and Their Precursors in Drinking Water Treatment

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 521
Author(s):  
Fernando J. Beltrán ◽  
Ana Rey ◽  
Olga Gimeno
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Humic Substances ◽  
Hypochlorous Acid ◽  
Drinking Water Treatment ◽  
Disinfection Byproducts ◽  
Catalytic Ozonation ◽  
Operating Conditions ◽  
Halogen Compounds ◽  
Radiation Sources

Formation of disinfection byproducts (DBPs) in drinking water treatment (DWT) as a result of pathogen removal has always been an issue of special attention in the preparation of safe water. DBPs are formed by the action of oxidant-disinfectant chemicals, mainly chlorine derivatives (chlorine, hypochlorous acid, chloramines, etc.), that react with natural organic matter (NOM), mainly humic substances. DBPs are usually refractory to oxidation, mainly due to the presence of halogen compounds so that advanced oxidation processes (AOPs) are a recommended option to deal with their removal. In this work, the application of catalytic ozonation processes (with and without the simultaneous presence of radiation), moderately recent AOPs, for the removal of humic substances (NOM), also called DBPs precursors, and DBPs themselves is reviewed. First, a short history about the use of disinfectants in DWT, DBPs formation discovery and alternative oxidants used is presented. Then, sections are dedicated to conventional AOPs applied to remove DBPs and their precursors to finalize with the description of principal research achievements found in the literature about application of catalytic ozonation processes. In this sense, aspects such as operating conditions, reactors used, radiation sources applied in their case, kinetics and mechanisms are reviewed.

Evaluation of enzyme activity for monitoring biofiltration performance in drinking water treatment

2021 ◽  
Vol 205 ◽  
pp. 117636
Author(s):  
Meaghan R. Keon ◽  
Michael J. McKie ◽  
Liz Taylor-Edmonds ◽  
Robert C. Andrews
Keyword(s):  
Drinking Water ◽  
Enzyme Activity ◽  
Water Treatment ◽  
Drinking Water Treatment

Effect of axial variation of flux on filtration characteristics of hollow fiber membrane for drinking water treatment

2007 ◽  
Vol 7 (4) ◽  
pp. 95-101
Author(s):  
Hyun-je Oh ◽  
June-Seok Choi ◽  
Byong-Bo Choi ◽  
Sangho Lee ◽  
Tae-Mun Hwang
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Hollow Fiber ◽  
Hollow Fiber Membrane ◽  
Drinking Water Treatment ◽  
Model Parameters ◽  
Fiber Membrane ◽  
Fiber System ◽  
Axial Distribution ◽  
Critical Flux

Understanding the fouling phenomena in submerged membrane systems is challenging because the efficiency of hollow fiber membrane highly depends on the dimensions of the fibers as well as filtration conditions. Thus, modeling filtration behavior of hollow fibers is important for improving the performance of hollow fiber system. In this work, a theoretical model based on critical flux concept was developed to simulate filtration resistance and axial pressure drop along the fiber in drinking water treatment. The application of a model for experimental data indicated that the model matches the experiments quite well. Thus, simulation of membrane system was carried out under various conditions using the parameters from the model fit. The axial distribution of pressure and flux affect the filtration characteristics of hollow fiber membranes. The effect of model parameters (specific cake resistance and critical flux) and module geometry were theoretically also investigated using the model.

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