Membrane filtration characteristics in membrane-coupled activated sludge system — the effect of physiological states of activated sludge on membrane fouling

Desalination ◽  
1998 ◽  
Vol 120 (3) ◽  
pp. 221-233 ◽  
Author(s):  
In-Soung Chang ◽  
Chung-Hak Lee
Keyword(s):  
Activated Sludge ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Activated Sludge System

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.

Occurrence of EPS in activated sludge from a membrane bioreactor treating municipal wastewater

2004 ◽  
Vol 50 (12) ◽  
pp. 293-300 ◽  
Author(s):  
H. Evenblij ◽  
J.H.J.M. van der Graaf
Keyword(s):  
Activated Sludge ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Municipal Wastewater ◽  
Water Phase ◽  
Simple Filtration ◽  
Paper Filter ◽  
Influence Of Substrate ◽  
Set Up ◽  
Substrate Addition

EPS are supposed to be among the causes of membrane fouling in membrane bioreactors (MBR). In this work they are measured as total proteins and total polysaccharides. Theoretical and empirical considerations of biomass membrane filtration lead to the conclusion that EPS in the water phase is decisive for the filterability of activated sludge. In this study therefore different ways of separating the water phase from the biomass are investigated, where a simple filtration over a paper filter turned out to be sufficient. Subsequently, a simple batch test set up was used to investigate the influence of substrate conditions on the amount of EPS in the water phase. Dilution of the biomass does not result in changes. Dilution together with substrate addition leads to an increase both in proteins and polysaccharides. Replacement of the water phase leads to no significant changes in protein concentration, but polysaccharide concentration may vary considerably. This phenomenon is more pronounced after replacement of the water phase and substrate addition.

Effects of membrane fouling on solute rejection during membrane filtration of activated sludge

2001 ◽  
Vol 36 (8-9) ◽  
pp. 855-860 ◽  
Author(s):  
In-Soung Chang ◽  
Soon-Ouk Bag ◽  
Chung-Hak Lee
Keyword(s):  
Activated Sludge ◽  
Membrane Fouling ◽  
Membrane Filtration

scholarly journals Effect of Current Density and Contact Time of Electro-Coagulation on the Characteristics of Activated Sludge and Membrane Filtration

2021 ◽  
Vol 43 (6) ◽  
pp. 428-438
Author(s):  
Kyeong-Rae Kim ◽  
In-Soung Chang
Keyword(s):  
Activated Sludge ◽  
Current Density ◽  
Membrane Fouling ◽  
Contact Time ◽  
Membrane Filtration ◽  
Extracellular Polymeric Substances ◽  
Similar Reduction ◽  
Dynamic Membrane ◽  
Before And After ◽  
Electro Coagulation

Objectives : The effect of current density and contact time of electro-coagulation on membrane fouling was investigated. In order to elucidate the reason why the membrane fouling was reduced by electro-coagulation, the changes in the characteristics of activated sludge were examined before and after electro-coagulation.Methods : A series of electro-coagulation of activated sludge suspensions was carried out with current density of 2.5, 6, 12, 24 A/m2 for 0, 2, 6, 12 hours. After membrane filtrations of the activated sludge suspensions, the membrane fouling was compared before and after the electro-coagulation. Characteristic changes in the activated sludge were also analyzed quantitatively.Results and Discussion : Total fouling resistances (Rt) of the electro-coagulated activated sludge decreased as current density and contact time increased. For example, Rt decreased 15%, 63% and 86% under the condition of current density of 24 A/m2 and 2, 6, 12 hours of contact time. Particularly, three activated sludge suspensions having very different initial MLSS concentrations showed a similar reduction of Rt, indicating that the membrane fouling was reduced not dominantly by particulates but by soluble foulants. The MLSS increased as current density increased, but MLVSS had not changed accordingly, which means that inorganic solids such as Al(OH)3 and AlPO4 produced during electro-coagulation were the main reasons for the increased MLSS concentration. These solids could play a key role in the reduction of membrane fouling by means of a dynamic membrane. As current density increased, the EPS (extracellular polymeric substances) and soluble COD concentration were reduced, which led to the reduction of membrane fouling. Soluble TN and TP were not significantly changed after electro-coagulation.Conclusions : The fouling materials, particularly, EPS and soluble COD decreased as current density and contact time increased, which played a key role in the reduction of membrane fouling. In addition, the insoluble solids produced during the electro-coagulation would act as a dynamic membrane, which led to fouling reduction.

Oxidation Ditch

2018 ◽  
Author(s):  
Gede H Cahyana
Keyword(s):  
Activated Sludge ◽  
Special Form ◽  
Oxidation Ditch ◽  
End Point ◽  
Activated Sludge System

As a part of activated sludge system, oxidation ditch has a special form like a canal without end point. Rotor is used to diffuse oxygen from air to the water.

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.

Parameters for Measuring the Activity and Viability of Activated Sludge

1974 ◽  
Vol 9 (1) ◽  
pp. 235-249 ◽  
Author(s):  
S.G. Nutt ◽  
K.L. Murphy
Keyword(s):  
Organic Carbon ◽  
Activated Sludge ◽  
Biological System ◽  
Analytical Methods ◽  
Heterogeneous System ◽  
Removal Rate ◽  
Bacterial Species ◽  
Atp Content ◽  
Culture Studies ◽  
Activated Sludge System

Abstract Conventional wastewater parameters are accepted as inadequate estimates of the condition of activated sludge but numerous other indices have been suggested as specific measurements of the activity and viability of the biomass. Literature in the related fields of microbiology and biochemistry were reviewed in order to select the most appropriate activity parameters for application to a heterogeneous biological material. Modified analytical methods were applied to a well-controlled biological system containing a single predominant bacterial species to evaluate the relative merit of each as an indicator of viability and activity. The potential of each parameter in a complex heterogeneous system was determined by monitoring each index in a bench activated sludge system. The predominant culture studies indicated that the ATP content of the biomass and the dehydrogenase activity were potential indicators of cell viability in a simple system. However, in the complex activated sludge system, only the ATP content showed significant correlation to the organic carbon removal rate.

TREATABILITY OF 2,4-D PRODUCTION WASTEWATERS

1994 ◽  
Vol 30 (3) ◽  
pp. 73-78 ◽  
Author(s):  
O. Tünay ◽  
S. Erden ◽  
D. Orhon ◽  
I. Kabdasli
Keyword(s):  
Hydrogen Peroxide ◽  
Activated Sludge ◽  
Partial Oxidation ◽  
Chloride Concentration ◽  
Chemical Oxidation ◽  
Cod Removal ◽  
Optimum Conditions ◽  
Organic Loading ◽  
Activated Sludge System ◽  
Biological Treatability

This study evaluates the characterization and treatability of 2,4-D production wastewaters. Wastewaters contain 20000-40000 mg/l COD, 17000-30000 mg/l chloride and pH is around 1.0. Chemical oxidation with hydrogen peroxide provided almost complete COD removal. The optimum conditions are 3:1 H2O2/COD oxidant dosage, 3000 mg/l Fe3+ as catalyst and pH 3. Partial oxidation at 0.5:1 H2O2//COD ratio is also effective providing 67% COD removal. A batch activated sludge system is used for biological treatability. Dilution is needed to maintain a tolerable chloride concentration which increases through COD removal. pH also increased during COD removal. 85% COD removal is obtained for the 50% dilution at an organic loading of 0.3 day‒1 on a COD basis. Completely and partially oxidized wastewaters are also treated in the activated sludge down to 30 mg/l BOD5.

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