Evaluating the membrane fouling formation and chemical cleaning strategy in forward osmosis membrane filtration treating domestic sewage

2018 ◽  
Vol 4 (12) ◽  
pp. 2092-2103 ◽  
Author(s):  
Nur Hafizah Ab Hamid ◽  
Liu Ye ◽  
David K. Wang ◽  
Simon Smart ◽  
Emmanuelle Filloux ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Nitrous Acid ◽  
Membrane Filtration ◽  
Forward Osmosis ◽  
Domestic Sewage ◽  
Chemical Cleaning ◽  
Free Nitrous Acid ◽  
Fouling Control ◽  
Filtration System ◽  
Time Required

Free nitrous acid (FNA) shows strong potential as an effective cleaning reagent in fouling control in a forward osmosis filtration system, with a relatively longer time required.

scholarly journals Effect of Pre-Oxidation on Coagulation/Ceramic Membrane Treatment of Yangtze River Water

Membranes ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 369
Author(s):  
Shengji Xia ◽  
Xinran Zhang ◽  
Yuanchen Zhao ◽  
Fibor J. Tan ◽  
Pan Li ◽  
...  
Keyword(s):  
Water Treatment ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Ceramic Membrane ◽  
Membrane Separation ◽  
Membrane System ◽  
Coagulation System ◽  
Fouling Control ◽  
Filtration System ◽  
Membrane Treatment

The membrane separation process is being widely used in water treatment. It is very important to control membrane fouling in the process of water treatment. This study was conducted to evaluate the efficiency of a pre-oxidation-coagulation flat ceramic membrane filtration process using different oxidant types and dosages in water treatment and membrane fouling control. The results showed that under suitable concentration conditions, the effect on membrane fouling control of a NaClO pre-oxidation combined with a coagulation/ceramic membrane system was better than that of an O3 system. The oxidation process changed the structure of pollutants, reduced the pollution load and enhanced the coagulation process in a pre-oxidation-coagulation system as well. The influence of the oxidant on the filtration system was related to its oxidizability and other characteristics. NaClO and O3 performed more efficiently than KMnO4. NaClO was more conducive to the removal of DOC, and O3 was more conducive to the removal of UV254.

Low-pressure membrane filtration with unconventional coagulation regimes

2005 ◽  
Vol 5 (5) ◽  
pp. 1-8 ◽  
Author(s):  
K.Y. Choi ◽  
B.A. Dempsey
Keyword(s):  
Activated Carbon ◽  
Membrane Filtration ◽  
Membrane Surface ◽  
Cross Flow ◽  
Chemical Cleaning ◽  
Sand Filters ◽  
Charge Neutralization ◽  
Floc Size ◽  
Filtration System ◽  
Pre Treatment

The objective of the research was to evaluate in-line coagulation to improve performance during ultrafiltration (UF). In-line coagulation means use of coagulants without removal of coagulated solids prior to UF. Performance was evaluated by removal of contaminants (water quality) and by resistance to filtration and recovery of flux after hydraulic or chemical cleaning (water production). We hypothesized that coagulation conditions inappropriate for conventional treatment, in particular under-dosing conditions that produce particles that neither settle nor are removed in rapid sand filters, would be effective for in-line coagulation prior to UF. A variety of pre-treatment processes for UF have been investigated including coagulation, powdered activated carbon (PAC) or granular activated carbon (GAC), adsorption on iron oxides or other pre-formed settleable solid phases, or ozonation. Coagulation pre-treatment is often used for removal of fouling substances prior to NF or RO. It has been reported that effective conventional coagulation conditions produced larger particles and this reduced fouling during membrane filtration by reducing adsorption in membrane pores, increasing cake porosity, and increasing transport of foulants away from the membrane surface. However, aggregates produced under sweep floc conditions were more compressible than for charge neutralization conditions, resulting in compaction when the membrane filtration system was pressurized. It was known that the coagulated suspension under either charge-neutralization or sweep floc condition showed similar steady-state flux under the cross-flow microfiltration mode. Another report on the concept of critical floc size suggested that flocs need to reach a certain critical size before MF, otherwise membranes can be irreversibly clogged by the coagulant solids. The authors were motivated to study the effect of various coagulation conditions on the performance of a membrane filtration system.

Treatment of highly-colored surface water by a hybrid microfiltration membrane system incorporating ion-exchange

2018 ◽  
Vol 19 (3) ◽  
pp. 855-863 ◽  
Author(s):  
T. Miyoshi ◽  
Y. Takahashi ◽  
T. Suzuki ◽  
R. Nitisoravut ◽  
C. Polprasert
Keyword(s):  
Surface Water ◽  
Hybrid System ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane System ◽  
Pilot Scale ◽  
Manganese Concentration ◽  
Moderate Increase ◽  
Coagulant Dosage ◽  
Filtration System

Abstract This study investigated the performance of a hybrid membrane filtration system to produce industrial water from highly-colored surface water. The system consists of a membrane filtration process with appropriate pretreatments, including coagulation, pre-chlorination, and anion exchange (IE) process. The results of the pilot-scale experiments revealed that the hybrid system can produce treated water with color of around 5 Pt-Co, dissolved manganese concentration of no more than 0.05 mg/L, and a silt density index (SDI) of no more than 5 when sufficient coagulant and sodium hypochlorite were dosed. Although the IE process effectively reduced the color of the water, a moderate increase in the color of the IE effluent was observed when there was a significant increase in the color of the raw water. This resulted in a severe membrane fouling, which was likely to be attributed to the excess production of inorganic sludge associated with the increased coagulant dosage required to achieve sufficient reduction of color. Such severe membrane fouling can be controlled by optimising the backwashing and relaxation frequencies during the membrane filtration. These results indicate that the hybrid system proposed is a suitable technology for treating highly-colored surface water.

Characteristics of coagulation-flocculation of humic acid with effective performance of polymeric flocculant and inorganic coagulant

2003 ◽  
Vol 47 (1) ◽  
pp. 89-95 ◽  
Author(s):  
J. Yu ◽  
D.D. Sun ◽  
J.H. Tay
Keyword(s):  
Humic Acid ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Molecular Size ◽  
Aluminium Sulphate ◽  
Fouling Control ◽  
Effective Performance ◽  
Water And Wastewater ◽  
Pre Treatment ◽  
Flocculation Process

Ferric chloride and aluminium sulphate as coagulants and positive charged flocculants PDDMAC ((PDDMAC = poly (diallyldimethylammonium chloride) were used for pre-treatment of water and wastewater for removing humic substance prior to RO membrane filtration. It was found that a combination of flocculant and coagulant enhanced the coagulation-flocculation process and humic acid removal. The optimum conditions of coagulation-flocculation were established in reference to the ratio of humic acid and coagulant. Zeta potential and the ratio of E4/E6 were investigated to explore the possible micro-mechanisms of coagulation-flocculation. The ratios of E4/E6 show the molecular size variations using different coagulants and flocculants, which are expected to benefit membrane-fouling control.

scholarly journals Optimization of In Situ Backwashing Frequency for Stable Operation of Anaerobic Ceramic Membrane Bioreactor

Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 545 ◽  
Author(s):  
Rathmalgodage Thejani Nilusha ◽  
Tuo Wang ◽  
Hongyan Wang ◽  
Dawei Yu ◽  
Junya Zhang ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Bioreactor ◽  
Ceramic Membrane ◽  
Pure Water ◽  
Ex Situ ◽  
Stable Operation ◽  
Chemical Cleaning ◽  
Cake Layer

The cost-effective and stable operation of an anaerobic ceramic membrane bioreactor (AnCMBR) depends on operational strategies to minimize membrane fouling. A novel strategy for backwashing, filtration and relaxation was optimized for stable operation of a side stream tubular AnCMBR treating domestic wastewater at the ambient temperature. Two in situ backwashing schemes (once a day at 60 s/day, and twice a day at 60 s × 2/day) maintaining 55 min filtration and 5 min relaxation as a constant were compared. A flux level over 70% of the initial membrane flux was stabilized by in situ permeate backwashing irrespective of its frequency. The in situ backwashing by permeate once a day was better for energy saving, stable membrane filtration and less permeate consumption. Ex situ chemical cleaning after 60 days’ operation was carried out using pure water, sodium hypochlorite (NaOCl), and citric acid as the order. The dominant cake layer was effectively reduced by in situ backwashing, and the major organic foulants were fulvic acid-like substances and humic acid-like substances. Proteobacteria, Firmucutes, Epsilonbacteria and Bacteroides were the major microbes attached to the ceramic membrane fouling layer which were effectively removed by NaOCl.

Flow Dynamic Effect in Cake Shape and Resistance in Membrane Filtration

2011 ◽  
Author(s):  
Aklilu T. G. Giorges ◽  
John A. Pierson
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Film Growth ◽  
Dynamic Effect ◽  
Extended Period ◽  
Flow Dynamics ◽  
Flux Rate ◽  
Filtration Resistance ◽  
Filter Surface ◽  
Filtration System

Membrane filtration is one of the methods for separating targeted material from a fluid stream. Membrane based filtration is applied in many areas of processing to separate and concentrate fluids. However, fouling and film growth at the filter surface is a major problem that causes loss in efficiency. The cake buildup during the filtration process is investigated experimentally to understand the affect of flow dynamics on the cake characteristics, shape and associated resistance. The experiments were conducted without and with shear generated using an impeller operated at various rotational speeds. The results illustrate that indeed the cake shape and character are affected by the flow dynamics that eventually influence filtration resistance. Likewise the filtrate rate and the cake shape significantly affect the flow dynamics. Furthermore, the filtration resistance is not only affected by the thickness of the cake, but also by how the cake is formed. After similar volumes of filtrate, the flux rate of 120 Lm−2hr−1 for 4.4 mm thick and 1.8 g cake is observed for dead-end filtration, while the flux rate of 600 Lm−2hr−1 for 1.1 mm thick and 0.35 g cake where observed with a shearing rate of 630 s−1. Understanding the size and characters of cake buildup is very important to designing a system to overcome the drawbacks associated with membrane fouling. Moreover, developing a technology with the cleaning process that removes or eliminates cake and maintains a reasonable flux for an extended period requires a thorough understanding of the filtration system geometry and flow dynamics.

Pretreatment processes for membrane filtration of raw water containing manganese

2001 ◽  
Vol 1 (5-6) ◽  
pp. 341-348 ◽  
Author(s):  
S. Takizawa ◽  
L. Fu ◽  
N. Pradhan ◽  
T. Ike ◽  
M. Ohtaki ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Fixed Bed ◽  
Experimental Studies ◽  
Manganese Concentration ◽  
Fluidised Bed ◽  
Raw Water ◽  
Biological Pretreatment ◽  
Manganese Removal ◽  
Time Required

Experimental studies on chemical and biological pretreatments in membrane filtration processes were carried out to removal manganese contained in raw water and to prevent membrane fouling due to manganese. Two types of the pretreatment reactors, i.e. the fluidised-bed and fixed-bed configurations, were compared in the biological pretreatment experiments. New synthetic media (tubular polypropylene, I.D. 3 mm, O.D. 4 mm, length 5 mm) were used in all three experiments as a manganese-oxidising catalyst. The chemical pretreatment using sodium hypochlorite was effective in manganese removal and controlling membrane fouling; more than 0.8 mg-Cl2/L of chlorine dose was necessary to bring the manganese concentration from 0.4 mg/L in raw water to less than 0.05 mg/L. The biological pretreatment for manganese removal required a long start-up period of more than 40 days. The fixed-bed biological pretreatment was superior in manganese removal and in control of membrane fouling to the fluidised-bed biological pretreatment, which showed wash-out of the attached bacteria resulting in membrane fouling. The linear velocity and the empty-bed retention time required for the treatment of 0.14 mg-Mn/L in the fixed-bed biological pretreatment was 206 m/d and 8.0 minutes, respectively.

Membrane Fouling and Hybrid Membrane Filtration System in Water Purification

MEMBRANE ◽  
2013 ◽  
Vol 38 (5) ◽  
pp. 207-214
Author(s):  
Yoshihisa Fujii ◽  
Sadaki Samitsu ◽  
Izumi Ichinose
Keyword(s):  
Water Purification ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Hybrid Membrane ◽  
Filtration System

scholarly journals Effect of vibration on the efficiency of ultrafiltration

2021 ◽  
Vol 15 (1) ◽  
pp. 37-44
Author(s):  
Szabolcs Gyula Szerencsés ◽  
Sándor Beszédes ◽  
Zsuzsanna László ◽  
Gábor Veréb ◽  
Balázs Szegedi ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Membrane Fouling ◽  
Energy Demand ◽  
Membrane Filtration ◽  
The European Union ◽  
Treatment Technology ◽  
Filtration Resistance ◽  
Filtration System ◽  
Total Filtration ◽  
Sustainable Wastewater Treatment

Nowadays, several environmental challenges are present to cope with. One with outstanding importance is the protection of our water supplies, therefore examination of wastewater treatment technology is a priority, especially in the European Union. In this work, the effect of membrane module vibration amplitude on the efficiency of ultrafiltration (UF) was investigated in a vibratory shear enhanced membrane filtration system. Based on the results of model dairy effluent UF and statistical analysis, the maximum vibration level available resulted in the most efficient filtration process, due to the most significant reduction of membrane fouling. From our results it was observed that the permeate fluxes more than doubled, specific energy demand was roughly halved, with almost identical retentions for organic matter, and total filtration resistance was reduced to less than half. Results also showed that setting the optimal operating parameters, an advantageous, efficiency focused, and sustainable wastewater treatment technology can be established.

scholarly journals UV and bacteriophages as a chemical-free approach for cleaning membranes from anaerobic bioreactors

2020 ◽  
Author(s):  
Giantommaso Scarascia ◽  
Luca Fortunato ◽  
Yevhen Myshkevych ◽  
Hong Cheng ◽  
TorOve Leiknes ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Bioreactor ◽  
Combined Treatment ◽  
Chemical Cleaning ◽  
High Quality ◽  
Anaerobic Membrane Bioreactor ◽  
Membrane Biofouling ◽  
Uv C

ABSTRACTAnaerobic membrane bioreactor (AnMBR) for wastewater treatment has attracted much interest due to its efficacy in providing high quality effluent with minimal energy costs. However, membrane biofouling represents the main bottleneck for AnMBR because it diminishes flux and necessitates frequent replacement of membranes. In this study, we assessed the feasibility of combining bacteriophages and UV-C irradiation to provide a chemical-free approach to remove biofoulants on the membrane. The combination of bacteriophage and UV-C resulted in better log cells removal and twice higher extracellular polymeric substance (EPS) concentration reduction in mature biofoulants compared to UV-C. A reduction in the relative abundance of Acinetobacter spp. and selected gram-positive bacteria associated with the membrane biofilm was also achieved by the new cleaning approach. Microscopic analysis further revealed the formation of cavities in the biofilm due to bacteriophages and UV-C irradiation, which would be beneficial to maintain water flux through the membrane. When the combined treatment was further compared with the common chemical cleaning procedure, a similar reduction on the cell numbers was observed (1.4 log). However, combined treatment was less effective in removing EPS compared with chemical cleaning. These results suggest that the combination of UV-C and bacteriophage have an additive effect in biofouling reduction, representing a potential chemical-free method to remove reversible biofoulants on membrane fitted in an anaerobic membrane bioreactor.SIGNIFICANCEAnaerobic membrane bioreactors can achieve high quality effluent with a reduced energy consumption. However, biofouling represents the main bottleneck for membrane filtration efficiency. Biofouling is commonly reduced through chemical treatment. These agents are often detrimental for the environment and health safety due to the formation of toxic byproducts. Therefore, we present a new approach, based on the additive antifouling action of bacteriophages infection and UV-C irradiation, to reduce anaerobic membrane biofouling. This new strategy could potentially delay the occurrence of membrane fouling by removing the reversible fouling layers on membranes, in turn reducing the frequencies and amount of chemicals needed throughout the course of wastewater treatment.

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