Influence of extracellular polysaccharides (EPS) produced by two different green unicellular algae on membrane filtration in an algae-based biofuel production process

2014 ◽  
Vol 69 (9) ◽  
pp. 1919-1925 ◽  
Author(s):  
Takaki Matsumoto ◽  
Hiroshi Yamamura ◽  
Jyunpei Hayakawa ◽  
Yoshimasa Watanabe ◽  
Shigeaki Harayama
Keyword(s):  
Green Algae ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Specific Growth ◽  
Biofuel Production ◽  
Extracellular Polysaccharides ◽  
Transmembrane Pressure ◽  
Unicellular Algae

In the present study, two strains of green algae named S1 and S2, categorized as the same species of Pseudo-coccomyxa ellipsoidea but showing 99% homology, were cultivated under the same conditions and filtrated with a microfiltration membrane. On the basis of the results of the extracellular polysaccharides (EPS) characteristics of these two green algae and the degree of fouling, the influence of these characteristics on the performance of membrane filtration was investigated. There was no difference in the specific growth rate between the S1 and S2 strains; however, large differences were seen in the amount and quality of EPS between S1 and S2. When the S1 and S2 strains were filtered with a membrane, the trend in the increase in transmembrane pressure (TMP) was quite different. The filtration of the S1 strain showed a rapid increase in TMP, whereas the TMP of the filtration of the S2 strain did not increase at all during the operation. This clearly demonstrated that the characteristics of each strain affect the development of membrane fouling. On the basis of the detailed characterization of solved-EPS (s-EPS) and bound-EPS (b-EPS), it was clarified that s-EPS mainly contributed to irreversible fouling for both operations and the biopolymer-like organic matter contained in b-EPS mainly contributed to reversible fouling.

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.

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.

scholarly journals The Use of Flat Ceramic Membranes for Purification of the Liquid Fraction of the Digestate from Municipal Waste Biogas Plants

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3947
Author(s):  
Agnieszka Urbanowska ◽  
Małgorzata Kabsch-Korbutowicz
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Liquid Fraction ◽  
Ceramic Membranes ◽  
Municipal Waste ◽  
Recycled Water ◽  
Sedimentation Process ◽  
Biogas Plants ◽  
Plant Membranes

Due to the rising water deficit in agriculture, digestate is increasingly being considered not only as an alternative fertiliser but also as a potential source of water. The use of recycled water for crop irrigation requires that it be treated in such a way that contaminants from the fermented biomass are not returned to the environment. Membrane processes can provide promising results in this regard. This study seeks to achieve membrane filtration using flat ceramic membranes for effective digestate liquid fraction treatment from a municipal waste biogas plant. Membranes of 1, 5, 15, and 50 kDa, and 0.14 and 0.45 µm are examined. The results obtained show that the application of a sedimentation process, as a preliminary step in the purification of the digestate, allows for a significant reduction in the content of contaminants in the solution. By analysing the effectiveness of the liquid fraction of the digestate purification in the sedimentation-membrane filtration process using flat ceramic membranes, it can be stated that all the membranes tested can be applied in the digestate purification. With an increase in the cut-off value, a deterioration in the quality of the digestate can be observed. The use of the sedimentation process before the membrane process not only improves the final quality of the digestate but also reduces the intensity of membrane fouling.

scholarly journals Membranes coupled with physico chemical treatment in water reuse

2010 ◽  
Vol 61 (2) ◽  
pp. 513-519 ◽  
Author(s):  
W. S. Guo ◽  
R. Zhang ◽  
S. Vigneswaran ◽  
H. H. Ngo ◽  
J. Kandasamy
Keyword(s):  
Membrane Fouling ◽  
Water Reuse ◽  
Membrane Filtration ◽  
Ion Exchange Resin ◽  
Transmembrane Pressure ◽  
Long Duration ◽  
Pre Treatment ◽  
Refractory Organic Pollutants ◽  
Treated Sewage Effluent ◽  
Magnetic Ion

In this study, short-term experiments were conducted with different configurations of membrane hybrid systems to treat biological treated sewage effluent containing refractory organic pollutants: (i) submerged hollow fiber microfiltration (SMF) alone; (ii) spiral flocculator (SF)-SMF without settling; (iii) SF-PAC-SMF without settling and (iv) SMF with magnetic ion exchange resin MIEX® pretreatment. The results indicated that the pre-flocculation of SF could improve the mitigation of membrane fouling significantly even when the system was operated at a high membrane filtration rate. The transmembrane pressure (TMP) of SF-PAC-SMF only increased marginally (0.8 kPa over 8 hours). SF-SMF without the addition of powdered activated carbon (PAC) also took a relatively long duration for the TMP to increase. The TMP only increased by 2.5 kPa over 8 hours. The SF-PAC-MF system resulted in a high dissolved organic carbon (DOC) removal of more than 96%. When used as pre-treatment to submerged membranes, the fluidized bed MIEX® contactor could remove a significant amount of organic matter in wastewater. This pre-treatment helped to reduce the membrane fouling and kept the TMP low during the membrane operation.

Dynamic modeling of fouling over multiple biofuel production cycles in a membrane reactor

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Thien An Huynh ◽  
Edwin Zondervan
Keyword(s):  
Membrane Fouling ◽  
Membrane Reactor ◽  
Membrane Filtration ◽  
Reaction System ◽  
Operating Conditions ◽  
Biodiesel Production ◽  
Biofuel Production ◽  
Cyclic Behavior ◽  
Permeate Flux ◽  
Production Cycles

Abstract In this paper, a novel mathematical model that combines a membrane filtration model, component balances and reaction kinetics models for an intensified separation-reaction process in membrane reactor producing biofuels was developed. A unique feature is that the proposed model can capture the dynamics of membrane fouling as function of both reversible and irreversible fouling; which leads to cyclic behavior. Fouling leads to the decline of the reactor productivity. With an appropriate fouling-model, the operational strategy can be optimized. In the case study of biodiesel production, the developed model was validated with experimental data. The model was in good agreement with the data, where R-squared are 0.96 for the permeate flux and 0.95 for the biodiesel yield. From a further analysis, the efficiency of membrane reaction system in term of productivity can be significantly improved by changing the backwashing frequency under specific operating conditions. As the backwashing frequency increased eight times, the biodiesel yield increased to more than two to three times before the permeate flux dropped under a predetermined limit due to the increase of irreversible membrane fouling.

scholarly journals Assessment of vibration amplitude and transmembrane pressure on vibratory shear enhanced membrane filtration for treating dairy wastewater

2021 ◽  
Vol 50 (1) ◽  
pp. 42-53
Author(s):  
Sz. Gy. Szerencsés ◽  
S. Beszédes ◽  
Zs. László ◽  
G. Veréb ◽  
D. Szalay ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Membrane Fouling ◽  
Vibration Amplitude ◽  
Membrane Filtration ◽  
Oxygen Demand ◽  
Dairy Wastewater ◽  
Transmembrane Pressure ◽  
Operational Parameters ◽  
Limit Values ◽  
Energy And Environment

AbstractIn this study, statistical analysis was performed to investigate the influence of operational parameters based on experimental results. The research aimed to know whether a long-term discontinuous module vibration operation is possible without adversely affecting filtration efficiency. Polymer membranes were compared by surface characteristics with contact angle measurements and selected for further membrane filtration experiments for dairy wastewater treatment. The effect of the main operational parameters, membrane module vibration amplitude (Avibr.) and transmembrane pressure (TMP), was investigated using a vibratory shear enhanced processing (VSEP) module with ultrafiltration (UF) and nanofiltration (NF) membranes. Components of the permeates, including chemical oxygen demand (COD), were measured, and membrane rejections were calculated to compare with threshold limit values. The results suggest that proper combination of Avibr. and TMP could mitigate membrane fouling. However, discontinuous module vibration resulted in more clogged membrane with lower fluxes, but slightly higher rejections. We conclude that investigating the significance of operational parameters is necessary for a wider, more energy and environment-friendly application in wastewater treatment.

scholarly journals Modeling of submerged membrane filtration processes using recurrent artificial neural networks

2020 ◽  
Vol 9 (1) ◽  
pp. 155
Author(s):  
Zakariah Yusof ◽  
Norhaliza Abdul Wahab ◽  
Syahira Ibrahim ◽  
Shafishuhaza Sahlan ◽  
Mashitah Che Razali
Keyword(s):  
Neural Network ◽  
Dynamic Behavior ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Dynamic Models ◽  
Transmembrane Pressure ◽  
Permeate Flux ◽  
Filtration Process ◽  
Absolute Deviation ◽  
Auto Regressive

<span lang="EN-US">The modeling of membrane filtration processes is a challenging task because it involves many interactions from both biological and physical operational behavior. Membrane fouling behaviour in filtration processes is complex and hard to understand, and to derive a robust model is almost not possible. Therefore, it is the aim of this paper to study the potential of time series neural network based dynamic model for a submerged membrane filtration process. The developed model that represent the dynamic behavior of filtration process is later used in control design of the membrane filtration processes. In order to obtain the dynamic behaviour of permeate flux and transmembrane pressure (TMP), a random step was applied to the suction pump. A recurrent neural network (RNN) structure was employed to perform as the dynamic models of a filtration process, based on nonlinear auto-regressive with exogenous input (NARX) model structure. These models are compared with the linear auto-regressive with exogenous input (ARX) model. The performance of the models were evaluated in terms of %<em>R<sup>2</sup></em>, mean square error (MSE,) and a mean absolute deviation (MAD). For filtration control performance, a proportional integral derivative (PID) controller was implemented. The results showed that the RNN-NARX structure able to model the dynamic behavior of the filtration process under normal conditions in short range of the filtration process. The developed model can also be a reliable assistant for two different control strategies development in filtration processes.</span>

Comparison of UV and chlorine pretreatment in pilot plant micro-filter membrane separation for drinking water

2001 ◽  
Vol 1 (5-6) ◽  
pp. 245-251
Author(s):  
J.Y. Huang ◽  
S. Takizawa ◽  
K. Fujita
Keyword(s):  
Uv Irradiation ◽  
Water Purification ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Separation ◽  
Pilot Scale ◽  
Transmembrane Pressure ◽  
Formation Potential ◽  
Dead End ◽  
Solids Removal

Methods to control bio-fouling, i.e. UV-irradiation and chlorination pretreatment were evaluated in dead-end membrane filtration. Pilot-scale experiments were carried out at Kosuzume Water Purification Plant, which is located at the Sagami River in Kanagawa Prefecture, Japan. As a result, both UV-irradiation and chlorination strongly suppressed the increase of transmembrane pressure and prevented bio-fouling. However, in the case of pre-chlorination, the membrane color changed from white to brown after a long use, causing irreversible membrane fouling due probably to manganese adsorption. Suspended solids removal by membrane filtration decreased the formation potential for CHCl3, but didn't affect the CHCl2Br and CHClBr2 formation potentials. Pre-chlorination, however, increased both CHCl2Br and CHClBr2 formation potentials, thus making up for the reduction in CHCl3 formation potential due to membrane filtration. UV-irradiation pretreatment combined with membrane filtration in the water purification process is regarded as an accessible method and was proved effective in controlling bio-fouling, which gave us a better water quality without increasing trihalomethanes in contrast to pre-chlorination.

scholarly journals Characterization of the Fouling Layer on the Membrane Surface in a Membrane Bioreactor: Evolution of the Foulants’ Composition and Aggregation Ability

Membranes ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 85 ◽  
Author(s):  
Linlin Yan ◽  
Ruixue Li ◽  
Yu Song ◽  
Yanping Jia ◽  
Zheng Li ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Extracellular Polymeric Substances ◽  
Membrane Surface ◽  
Extracellular Dna ◽  
Transmembrane Pressure ◽  
Average Roughness ◽  
Three Stages ◽  
Fast Rise

In this study, the characteristics of membrane foulants were analyzed with regard to morphology, composition, and aggregation ability during the three stages of transmembrane pressure (TMP) development (fast–slow–fast rise in TMP) in a steady operational membrane bioreactor (MBR). The results obtained show that the fouling layer at the slow TMP-increase stage possessed a higher average roughness (71.27 nm) and increased fractal dimension (2.33), which resulted in a low membrane fouling rate (0.87 kPa/d). A higher extracellular DNA (eDNA) proportion (26.12%) in the extracellular polymeric substances (EPS) resulted in both higher zeta potential (-23.3 mV) and higher hydrophobicity (82.3%) for initial foulants, which induced and increased the protein proportion in the subsequent fouling layer (74.11%). Furthermore, the main composition of the EPS shifted from protein toward polysaccharide dominance in the final fouling layer. The aggregation test confirmed that eDNA was essential for foulant aggregation in the initial fouling layer, whereas ion interaction significantly affected foulant aggregation in the final fouling layer.

Physicochemical and bacteriological characterization of hospital effluents and their impact on the environment

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Human Health ◽  
Fecal Coliforms ◽  
Chemical Pollution ◽  
Hospital Effluents ◽  
Biological Contaminants ◽  
Almost All ◽  
Direct Discharge ◽  
Significant Chemical

Liquid effluents discharged by hospitals may contain chemical and biological contaminants whose main source is the different substances used for the treatment of patients. This type of rejection can present a sanitary potentially dangerous risk for human health and can provoke a strong degradation of diverse environmental compartments mainly water and soils. The present study focuses on the quality of the liquid effluents of Hassani Abdelkader’s hospital of Sidi Bel-Abbes (West of Algeria). The results reveal a significant chemical pollution (COD: 879 mgO2/L, BOD5: 850 mgO2/L, NH4+ : 47.9 mg/l, NO2- : 4.2 mg/l, NO3- : 56.8 mg/l with respect to WHO standard of 90 mgO2/L, 30 mgO2/L, 0.5 mg/l, 1 mg/l and 1 mg/l respectively). However, these effluents are biodegradable since the ratio COD/BOD5 do not exceeded the value of 2 in almost all samples. The presence of pathogen germs is put into evidence such as pseudomonas, the clostridium, the staphylococcus, the fecal coliforms and fecal streptococcus. These results show that the direct discharge of these effluents constitutes a major threat to human health and the environment.

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