scholarly journals SMP Production in an Anaerobic Submerged Membrane Bioreactor (AnMBR) at Different Organic Loading Rates

Membranes ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 317
Author(s):  
Sandra C. Medina ◽  
Nataly Zamora-Vacca ◽  
Hector J. Luna ◽  
Nicolas Ratkovich ◽  
Manuel Rodríguez Susa
Keyword(s):  
Membrane Fouling ◽  
Energy Demand ◽  
Membrane Surface ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Term Operation ◽  
Submerged Membrane Bioreactor ◽  
Anaerobic Membrane Bioreactors ◽  
Microbial Products

Anaerobic membrane bioreactors (AnMBRs) have demonstrated an excellent capability to treat domestic wastewater. However, biofouling reduces membrane permeability, increasing operational costs and overall energy demand. Soluble microbial products (SMPs) that build up on the membrane surface play a significant role in the biofouling. In this study, the production of SMPs in a 32 L submerged AnMBR operated at three different organic loads (3.0, 4.1 and 1.2 kg chemical oxygen demand (COD)/m3d for phases 1, 2 and 3, respectively) during long-term operation of the reactor (144, 83 and 94 days) were evaluated. The samples were taken from both the permeate and the sludge at three different heights (0.14, 0.44 and 0.75 m). Higher production of SMPs was obtained in phase 2, which was proportional to the membrane fouling. There were no statistically significant differences (p > 0.05) in the SMPs extracted from sludge at different heights among the three phases. In the permeate of phases 1, 2 and 3, the membrane allowed the removal of 56%, 70% and 64% of the SMP concentration in the sludge. SMPs were characterized by molecular weight (MW). A bimodal behavior was obtained, where fractions prevailed with an MW < 1 kDa, associated with SMPs as utilization-associated products (UAPs) caused fouling by the pore-blocking mechanism. The chemical analysis found that, in the SMPs, the unknown COD predominated over the known COD, such as carbohydrates and proteins. These results suggest that further studies in SMP characterization should focus on the unknown COD fraction to understand the membrane fouling in AnMBR systems better.

scholarly journals Effect of applied voltage on membrane fouling in the amplifying anaerobic electrochemical membrane bioreactor for long-term operation

RSC Advances ◽  
2021 ◽  
Vol 11 (50) ◽  
pp. 31364-31372
Author(s):  
Mengjing Cao ◽  
Yongxiang Zhang ◽  
Yan Zhang
Keyword(s):  
Chemical Oxygen Demand ◽  
Applied Voltage ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Glucose Solution ◽  
Oxygen Demand ◽  
Term Operation ◽  
Long Time

A novel and amplifying anaerobic electrochemical membrane bioreactor was constructed and operated for a long time (204 days) with synthetic glucose solution having an average chemical oxygen demand (COD) of 315 mg L−1, at different applied voltages and room temperatures.

scholarly journals Effect of Mixed Liquor Volatile Suspended Solids on Membrane Fouling During Short and long-term Operation of Membrane Bioreactor

2015 ◽  
Vol 11 (21) ◽  
pp. 137-155 ◽  
Author(s):  
Edson Baltazar Estrada-Arriaga ◽  
Petia Mijaylova Nacheva ◽  
Liliana García-Sánchez
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Suspended Solids ◽  
Membrane Surface ◽  
Waste Water Treatment ◽  
Critical Flux ◽  
Term Operation ◽  
Mixed Liquor ◽  
Submerged Membrane Bioreactor ◽  
The Impact

The aim of this study was to examine the impact of different Mixed Liquor Volatile Suspended Solids (MLVSS) concentrations on membrane fouling,in a submerged Membrane Bioreactor (MBR) at short and longterm MBRoperation for waste water treatment. Three laboratory-scale in a submerged MBR system were operated under critical flux, subcritical flux,and an intermittent suction time and backwashing conditions. At short-term MBR operation with mixed liquors of 4,200 and 6,150 mg MLVSSL−1, the hydraulic resistance of membranes followed a same trajectory with averages of 5.0E+12m−1, whereas for 7,940 mg MLVSSL−1, a highresistance of up to 1.7E+13m−1was obtained. The result showed thathigh biomass concentrations decreased to permeability due to a bio-layer formed in the membrane surface and high Extracellular Polymeric Substance (EPS).

Fouling and long-term durability of an integrated forward osmosis and membrane distillation system

2015 ◽  
Vol 72 (11) ◽  
pp. 2000-2005 ◽  
Author(s):  
T. Husnain ◽  
B. Mi ◽  
R. Riffat
Keyword(s):  
Membrane Fouling ◽  
Tap Water ◽  
Membrane Surface ◽  
Wastewater Reuse ◽  
Forward Osmosis ◽  
Cross Flow ◽  
Domestic Wastewater ◽  
Membrane Distillation ◽  
Hydrophobic Membrane

An integrated forward osmosis (FO) and membrane distillation (MD) system has great potential for sustainable wastewater reuse. However, the fouling and long-term durability of the system remains largely unknown. This study investigates the fouling behaviour and efficiency of cleaning procedures of FO and MD membranes used for treating domestic wastewater. Results showed that a significant decline in flux of both FO and MD membranes were observed during treatment of wastewater with organic foulants. However, shear force generated by the increased cross-flow physically removed the loosely attached foulants from the FO membrane surface and resulted in 86–88% recovery of flux by cleaning with tap water. For the MD membrane, almost no flux recovery was achieved due to adsorption of organic foulants on the hydrophobic membrane surface, thus indicating significant irreversible fouling/wetting, which may not be effectively cleaned even with chemical reagents. Long-term (10 d) tests showed consistent performance of the FO membrane by rejecting the contaminants. However, organic foulants reduced the hydrophobicity of the MD membrane, caused wetting problems and allowed contaminants to pass through. The results demonstrate that combination of the FO and MD processes can effectively reduce irreversible membrane fouling and solve the wetting problem of the MD membrane.

scholarly journals Multivariate Chemometric Analysis of Membrane Fouling Patterns in Biofilm Ceramic Membrane Bioreactor

Water ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 982 ◽  
Author(s):  
Olga Kulesha ◽  
Zakhar Maletskyi ◽  
Harsha Ratnaweera
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Ceramic Membrane ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Operating Conditions ◽  
Volume Index ◽  
Least Squares Regression ◽  
Effective Lifetime ◽  
Term Operation

Membrane fouling highly limits the development of Membrane bioreactor technology (MBR), which is among the key solutions to water scarcity. The current study deals with the determination of the fouling propensity of filtered biomass in a pilot-scale biofilm membrane bioreactor to enable the prediction of fouling intensity. The system was designed to treat domestic wastewater with the application of ceramic microfiltration membranes. Partial least squares regression analysis of the data obtained during the long-term operation of the biofilm-MBR (BF-MBR) system demonstrated that Mixed liquor suspended solids (MLSS), diluted sludge volume index (DSVI), chemical oxygen demand (COD), and their slopes are the most significant for the estimation and prediction of fouling intensity, while normalized permeability and its slope were found to be the most reliable fouling indicators. Three models were derived depending on the applied operating conditions, which enabled an accurate prediction of the fouling intensities in the system. The results will help to prevent severe membrane fouling via the change of operating conditions to prolong the effective lifetime of the membrane modules and to save energy and resources for the maintenance of the system.

Investigation of long-term operation and biomass activity in a membrane bioreactor system

2011 ◽  
Vol 63 (9) ◽  
pp. 1906-1912 ◽  
Author(s):  
Simos Malamis ◽  
Andreas Andreadakis ◽  
Daniel Mamais ◽  
Constantinos Noutsopoulos
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Extracellular Polymeric Substances ◽  
Operating Conditions ◽  
Term Operation ◽  
Solids Retention ◽  
Biomass Activity ◽  
Long Term Performance ◽  
Term Performance

The aim of this work was to evaluate the long-term performance of a Membrane Bioreactor (MBR) that operated continuously for 2.5 years and to assess membrane fouling and biomass activity under various operating conditions. Furthermore, a method for the characterisation of influent wastewater was developed based on its separation into various fractions. The MBR system operated at the solids retention times (SRT) of 10, 15, 20 and 33 days. The increase of SRT resulted in a decrease of the fouling rate associated with the reduction of extracellular polymeric substances. Moreover, the SRT increase resulted in a significant reduction of the Oxygen Uptake Rate (OUR) due to the lower availability of substrate and in a notable decrease of the maximum OUR since high SRT allowed the development of slower growing microorganisms. Biomass consisted of small flocs due to extensive deflocculation caused by intense aeration. Finally, the method developed for wastewater characterisation is straightforward and less time consuming than the usual method that is employed.

Fouling cake layer in a submerged anaerobic membrane bioreactor treating saline wastewaters: curse or a blessing?

2011 ◽  
Vol 63 (12) ◽  
pp. 2902-2908 ◽  
Author(s):  
I. Vyrides ◽  
D. C. Stuckey
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Large Fraction ◽  
Membrane Bioreactors ◽  
Extracellular Polysaccharides ◽  
Cake Layer ◽  
Anaerobic Membrane Bioreactors ◽  
Suspended Biomass ◽  
Microbial Products

The treatment of inhibitory (saline) wastewaters is known to produce considerable amounts of soluble microbial products (SMPs), and this has been implicated in membrane fouling; the fate of these SMPs was of considerable interest in this work. This study also investigated the contribution of SMPs to membrane fouling of the; (a) cake layer/biofilm layer, (b) the compounds below the biofilm/cake layer and strongly attached to the surface of the membrane, (c) the compounds in the inner pores of the membrane, and (d) the membrane. It was found that the cake/biofilm layer was the main reason for fouling of the membrane. Interestingly, the bacteria attached to the cake/biofilm layer showed higher biodegradation rates compared with the bacteria in suspension. Moreover, the bacteria attached to the cake layer showed higher amounts of attached extracellular polysaccharides (EPS) compared with the bacteria in suspension, possibly due to accumulation of the released EPS from suspended biomass in the cake/biofilm layer. Molecular weight (MW) analysis of the effluent and reactor bulk showed that the cake layer can retain a large fraction of the SMPs in the reactor and prevent them from being released into the effluent. Hence, while cake layers lead to lower fluxes in submerged anaerobic membrane bioreactors (SAMBRs), and hence higher costs, they can improve the quality of the reactor effluent.

Influence of humic acid on the long-term performance of direct contact membrane distillation

2018 ◽  
Vol 30 (1) ◽  
pp. 109-120 ◽  
Author(s):  
Dong-Wan Cho ◽  
Gihoon Kwon ◽  
Jeongmin Han ◽  
Hocheol Song
Keyword(s):  
Humic Acid ◽  
Membrane Fouling ◽  
Coalbed Methane ◽  
Direct Contact ◽  
Membrane Surface ◽  
Membrane Distillation ◽  
Permeate Flux ◽  
Direct Contact Membrane Distillation ◽  
High Level

In this study, the influence of humic acid on the treatment of coalbed methane water by direct contact membrane distillation was examined with bench-scale test unit. During short-term distillation (1000 min), high level of humic acid above 50 ppm resulted in significant decrease in permeate flux, while low level of humic acid (∼2 ppm) had little influence on the flux. For the long-term distillation (5000 min), the flux decline began at 3400 min in the presence of 5 ppm humic acid and 5 mM Ca2+, and decreased to ∼40% of initial flux at 5000 min. The spectroscopic analysis of the membrane used revealed that the surface was covered by hydrophilic layers mainly composed of calcite. The membrane fouling effect of humic acid became more significant in the presence of Ca2+ due to more facile calcite formation on the membrane surface. It was demonstrated that humic acid enhanced CaCO3 deposition on the membrane surfaces, thereby expediting the scaling phenomenon.

scholarly journals Biomass Characteristics and Their Effect on Membrane Bioreactor Fouling

Molecules ◽  
2019 ◽  
Vol 24 (16) ◽  
pp. 2867 ◽  
Author(s):  
Petros K. Gkotsis ◽  
Anastasios I. Zouboulis
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Suspended Solids ◽  
Extracellular Polymeric Substances ◽  
Membrane Surface ◽  
Membrane Resistance ◽  
Soluble Microbial Products ◽  
Gelling Properties ◽  
Microbial Products ◽  
Soluble Part

Biomass characteristics are regarded as particularly influential for fouling in Membrane Bio-Reactors (MBRs). They primarily include the Mixed Liquor Suspended Solids (MLSS), the colloids and the Extracellular Polymeric Substances (EPS). Among them, the soluble part of EPS, which is also known as Soluble Microbial Products (SMP), is the most significant foulant, i.e., it is principally responsible for membrane fouling and affects all fundamental fouling indices, such as the Trans-Membrane Pressure (TMP) and the membrane resistance and permeability. Recent research in the field of MBRs, tends to consider the carbohydrate fraction of SMP (SMPc) the most important characteristic for fouling, mainly due to the hydrophilic and gelling properties, which are exhibited by polysaccharides and allow them to be easily attached on the membrane surface. Other wastewater and biomass characteristics, which affect indirectly membrane fouling, include temperature, viscosity, dissolved oxygen (DO), foaming, hydrophobicity and surface charge. The main methods employed for the characterization and assessment of biomass quality, in terms of filterability and fouling potential, can be divided into direct (such as FDT, SFI, TTF100, MFI, DFCM) or indirect (such as CST, TOC, PSA, RH) methods, and they are shortly presented in this review.

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