Coagulation as a pretreatment of SFBW for membrane filtration

2002 ◽  
Vol 2 (5-6) ◽  
pp. 301-306 ◽  
Author(s):  
A. Nasser ◽  
Z. Huberman ◽  
L. Dean ◽  
F. Bonner ◽  
A. Adin
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Size Range ◽  
Water Source ◽  
Protozoan Parasites ◽  
Pilot Studies ◽  
Major Barrier ◽  
Particle Count ◽  
Filtration Cycle ◽  
Granular Filtration

Granular filtration has been incorporated as a major barrier to prevent the dissemination of disease-causing agents by drinking water. Particles and pathogens such as Giardia lamblia and Cryptosporidium parvum retained in the filters are then washed by utilizing clean water. This study was conducted, primarily, to evaluate coagulation as a pretreatment for the Spent Filter Backwash Water (SFBW) treatment by ultrafiltration (UF). SFBW Samples were collected from four different water treatment plants and carefully analyzed. Jar-tests and backwash pilot studies were performed in the laboratory. Depending on the water source, protozoan parasites and viruses were found to be prevalent in SFBW. The results show that turbidity cannot serve as a surrogate for the microbial load of the SFBW. Alum flocculation pretreatment of SFBW was found to be effective in reducing turbidity, particle count, viruses and parasites, consequently it may also reduce membrane fouling. Settling the SFBW prior to flocculation did not enhance the removal of turbidity and particle count as compared to the unsettled SFBW samples. This finding might imply that settling would not be required prior to UF. The largest remaining particle fraction after alum flocculation was 3-10 μm in size, both Cryptosporidium and Giardia are found in this size range. Coagulation enhanced the removal of small size particles and may result in extending the filtration cycle by reducing the SFBW fouling potential.

Particle count and size alteration for membrane fouling reduction in non-conventional water filtration

2004 ◽  
Vol 50 (12) ◽  
pp. 273-278 ◽  
Author(s):  
A. Adin
Keyword(s):  
Activated Sludge ◽  
Ferric Chloride ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Positive Impact ◽  
Iron Chloride ◽  
Particle Count ◽  
Membrane Flux ◽  
Total Particle ◽  
Stirred Cell

If coagulation is not completely successful and produces aggregates which are too small, fouling may increase. In some cases, a deep-bed filter could perhaps provide a solution. The paper examines these effects using experimental results for different waters. Activated sludge effluents, stormy seawater containing microalgae and spent filter backwash water (SFBW) were coagulated by alum or ferric chloride. Sand filtration tests were carried out. Tests were performed in a membrane filtration stirred cell, filtration pilot plant equipped with SDI analyzer (seawater) and pilot UF plant (SFBW). For activated sludge effluent, alum residual ratio curves of turbidity and total particle count (TPC) followed one another. With ferric chloride, low coagulant dosage showed negative turbidity removal. Contact granular filtration reduced membrane fouling intensity. Increasing the dose resulted in higher improvement in membrane flux. For seawater, a filter run period under storm conditions reached 35 hours with satisfactory filtrate quality. An iron chloride dose of 0.3 mg/l during normal conditions and 0.5 mg/l for stormy condition should be injected, mixed well before the filters, while maintaining 10 m/hr filtration rate and pH 6.8 value. For SFBW, alum flocculation pretreatment of SFBW was effective in reducing turbidity, TPC, viruses and protozoa. SFBW settling prior to flocculation did not enhance turbidity and TPC removal. The largest remaining particle fraction after alum flocculation was 3-10 μm in size, both Cryptosporidium and Giardia are found in this size range. Coagulation enhanced the removal of small size particles, a positive impact on reducing membrane fouling potential.

Coagulation/flocculation/ultrafiltration for natural organic matter removal in drinking water production

2004 ◽  
Vol 4 (5-6) ◽  
pp. 215-222 ◽  
Author(s):  
A.R. Costa ◽  
M.N. de Pinho
Keyword(s):  
Drinking Water ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Surface ◽  
Water Production ◽  
Cellulose Acetate Membranes ◽  
Wide Range ◽  
Drinking Water Production

Membrane fouling by natural organic matter (NOM), namely by humic substances (HS), is a major problem in water treatment for drinking water production using membrane processes. Membrane fouling is dependent on membrane morphology like pore size and on water characteristics namely NOM nature. This work addresses the evaluation of the efficiency of ultrafiltration (UF) and Coagulation/Flocculation/UF performance in terms of permeation fluxes and HS removal, of the water from Tagus River (Valada). The operation of coagulation with chitosan was evaluated as a pretreatment for minimization of membrane fouling. UF experiments were carried out in flat cells of 13.2×10−4 m2 of membrane surface area and at transmembrane pressures from 1 to 4 bar. Five cellulose acetate membranes were laboratory made to cover a wide range of molecular weight cut-off (MWCO): 2,300, 11,000, 28,000, 60,000 and 75,000 Da. Severe fouling is observed for the membranes with the highest cut-off. In the permeation experiments of raw water, coagulation prior to membrane filtration led to a significant improvement of the permeation performance of the membranes with the highest MWCO due to the particles and colloidal matter removal.

Clogging in Irrigation Systems Reusing Pond Effluents and its Prevention

1987 ◽  
Vol 19 (12) ◽  
pp. 323-328 ◽  
Author(s):  
A. Adin
Keyword(s):  
Size Range ◽  
Small Scale ◽  
Main Obstacle ◽  
Reservoir Systems ◽  
Deep Reservoir ◽  
Particulate Removal ◽  
Oxidation Ponds ◽  
Surface Filtration ◽  
Granular Filtration ◽  
Low Rate

The clogging of emitters, orifices or laterals has turned out to be the main obstacle for further use of low rate applicators in wastewater irrigation. Granular filtration and screen filtration were studied and compared for particulate removal using small-scale pilot experiments. The removal ratio of particles larger than 10 µm in direct granular filtration was relatively large while smaller particles showed little removal. Particles in the 10-60µm size range were removed by 40–50 percent in depth and by 80 percent when surface filtration prevailed. Screen filters removed only 1–2 percent of the material but this was sufficient to cause their clogging. A release of particles from the screen into the effluent was observed, resulting in greater number of larger particles and thus greater clogging potential down the irrigation line. Deep-bed granular coarse media filters may serve for the control of particle size in effluents of oxidation ponds - deep reservoir systems while the conventional strainers are less recommended for this purpose.

scholarly journals Potential Pitfalls in Membrane Fouling Evaluation: Merits of Data Representation as Resistance Instead of Flux Decline in Membrane Filtration

Membranes ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 460
Author(s):  
Bastiaan Blankert ◽  
Bart Van der Bruggen ◽  
Amy E. Childress ◽  
Noreddine Ghaffour ◽  
Johannes S. Vrouwenvelder
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Data Representation ◽  
Strong Impact ◽  
Experimental Conditions ◽  
Permeable Membrane ◽  
Dead End ◽  
Flux Decline ◽  
The Difference ◽  
Filtration Flux

The manner in which membrane-fouling experiments are conducted and how fouling performance data are represented have a strong impact on both how the data are interpreted and on the conclusions that may be drawn. We provide a couple of examples to prove that it is possible to obtain misleading conclusions from commonly used representations of fouling data. Although the illustrative example revolves around dead-end ultrafiltration, the underlying principles are applicable to a wider range of membrane processes. When choosing the experimental conditions and how to represent fouling data, there are three main factors that should be considered: (I) the foulant mass is principally related to the filtered volume; (II) the filtration flux can exacerbate fouling effects (e.g., concentration polarization and cake compression); and (III) the practice of normalization, as in dividing by an initial value, disregards the difference in driving force and divides the fouling effect by different numbers. Thus, a bias may occur that favors the experimental condition with the lower filtration flux and the less-permeable membrane. It is recommended to: (I) avoid relative fouling performance indicators, such as relative flux decline (J/J0); (II) use resistance vs. specific volume; and (III) use flux-controlled experiments for fouling performance evaluation.

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.

scholarly journals Application of Hybrid Process of Coagulation/Flocculation and Membrane Filtration for the Removal of Protozoan Parasites from Water

10.5772/51287 ◽  
2013 ◽  
Author(s):  
Leticia Nishi ◽  
Angelica Marquetotti Salcedo Vieira ◽  
Ana Lucia Falavigna Guilherme ◽  
Milene Carvalho ◽  
Gabriel Francisco da Silva ◽  
...  
Keyword(s):  
Membrane Filtration ◽  
Hybrid Process ◽  
Protozoan Parasites

scholarly journals Membrane Fouling Controlled by Adjustment of Biological Treatment Parameters in Step-Aerating MBR

Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 553
Author(s):  
Dimitra C. Banti ◽  
Manassis Mitrakas ◽  
Petros Samaras
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Municipal Wastewater ◽  
Operating Conditions ◽  
Transmembrane Pressure ◽  
Aeration Tank ◽  
Filamentous Bacteria ◽  
Membrane Performance ◽  
Low Concentrations ◽  
Fouling Reduction

A promising solution for membrane fouling reduction in membrane bioreactors (MBRs) could be the adjustment of operating parameters of the MBR, such as hydraulic retention time (HRT), food/microorganisms (F/M) loading and dissolved oxygen (DO) concentration, aiming to modify the sludge morphology to the direction of improvement of the membrane filtration. In this work, these parameters were investigated in a step-aerating pilot MBR that treated municipal wastewater, in order to control the filamentous population. When F/M loading in the first aeration tank (AT1) was ≤0.65 ± 0.2 g COD/g MLSS/d at 20 ± 3 °C, DO = 2.5 ± 0.1 mg/L and HRT = 1.6 h, the filamentous bacteria were controlled effectively at a moderate filament index of 1.5–3. The moderate population of filamentous bacteria improved the membrane performance, leading to low transmembrane pressure (TMP) at values ≤2 kPa for a great period, while at the control MBR the TMP gradually increased reaching 14 kPa. Soluble microbial products (SMP), were also maintained at low concentrations, contributing additionally to the reduction of ΤΜP. Finally, the step-aerating MBR process and the selected imposed operating conditions of HRT, F/M and DO improved the MBR performance in terms of fouling control, facilitating its future wider application.

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.

Comparative study on membrane fouling between membrane-coupled moving bed biofilm reactor and conventional membrane bioreactor for municipal wastewater treatment

2013 ◽  
Vol 69 (5) ◽  
pp. 1021-1027 ◽  
Author(s):  
W. Yang ◽  
W. Syed ◽  
H. Zhou
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Bioreactor ◽  
Municipal Wastewater ◽  
Biofilm Reactor ◽  
Municipal Wastewater Treatment ◽  
Moving Bed Biofilm Reactor ◽  
Reactor Unit ◽  
Polyaluminum Chloride ◽  
Moving Bed

This study compared the performance between membrane-coupled moving bed biofilm reactor (M-MBBR) and a conventional membrane bioreactor (MBR) in parallel. Extensive tests were conducted in three pilot-scale experimental units over 6 months. Emphasis was placed on the factors that would affect the performance of membrane filtration. The results showed that the concentrations of soluble microbial product (SMP), colloidal total organic carbon and transparent exopolymer particles in the M-MBBR systems were not significantly different from those in the control MBR system. However, the fouling rates were much higher in the M-MBBR systems as compared to the conventional MBR systems. This indicates membrane fouling potential was related not only to the concentration of SMP, but also to their sources and characteristics. The addition of polyaluminum chloride could reduce the fouling rate of the moving bed biofilm reactor unit by 56.4–84.5% at various membrane fluxes.

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