Treatment of hypersaline produced water employing a moderately halophilic bacterial consortium in a membrane bioreactor: Effect of salt concentration on organic removal performance, mixed liquor characteristics and membrane fouling

The combined effect of acrylonitrile butadiene styrene (ABS) spherical beads and granular activated carbon (GAC) particles as fluidized media on the performance of anaerobic fluidized bed membrane bioreactor (AFMBR) was investigated. GAC particles and ABS beads were fluidized together in a single AFMBR to investigate membrane fouling and organic removal efficiency as well as energy consumption. The density difference between these two similarly sized media caused the stratified bed layer where ABS beads are fluidized above the GAC along the membrane. Membrane relaxation was effective to reduce the fouling and trans-membrane pressure (TMP) below 0.25 bar could be achieved at 6 h of hydraulic retention time (HRT). More than 90% of soluble chemical oxygen demand (SCOD) was removed after 80 d operation. Biogas consisting of 65% of methane was produced by AFMBR, suggesting that combined use of GAC and ABS beads did not have any adverse effect on methane production during the operational period. Scanning Electron Microscope (SEM) examinations showed the adherence of microbes to both media. However, 16S rRNA results revealed that fewer microbes attached to ABS beads than GAC. There were also compositional differences between the ABS and GAC microbial communities. The abundance of the syntrophs and exoelectrogens population on ABS beads was relatively low compared to that of GAC. Our result implied that syntrophic synergy and possible occurrence of direct interspecies electron transfer (DIET) might be facilitated in AFMBR by GAC, while traditional methanogenic pathways were dominant in ABS beads. The electrical energy required was 0.02 kWh/m3, and it was only about 13% of that produced by AFMBR.

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

Ingeniería y Ciencia ◽

10.17230/ingciencia.11.21.7 ◽

2015 ◽

Vol 11 (21) ◽

pp. 137-155 ◽

Cited By ~ 4

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).

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Effects of electrochemical processes application on the modification of mixed liquor characteristics of an electro-membrane bioreactor (e-MBR)

Water Science & Technology ◽

10.2166/wst.2018.522 ◽

2018 ◽

Vol 78 (11) ◽

pp. 2364-2373 ◽

Cited By ~ 1

Author(s):

André Aguiar Battistelli ◽

Rayra Emanuelly da Costa ◽

Leonardo Dalri-Cecato ◽

Tiago José Belli ◽

Flávio Rubens Lapolli

Keyword(s):

Electric Field ◽

Membrane Fouling ◽

Membrane Bioreactor ◽

Extracellular Polymeric Substances ◽

Municipal Wastewater ◽

Municipal Wastewater Treatment ◽

Floc Size ◽

Mixed Liquor ◽

Average Value ◽

Electrochemical Processes

Abstract This study evaluated the effects of electrochemical processes on the mixed liquor characteristics of an electro-membrane bioreactor (e-MBR) applied to municipal wastewater treatment. A laboratory-scale e-MBR was assessed under two experimental runs: without the electric field (run I) and with electric field, controlled by the application of an electric current set in 10.0 A m−2 under intermittent exposure mode of 6 minutes ON/18 minutes OFF (run II). The electric field caused approximately 55% removal of both soluble microbial products (SMP) and extracellular polymeric substances (EPS), whereas the proteins/carbohydrates ratio in EPS was increased from 1.9 in the run I to 2.9 in run II, leading to an increment of flocs' hydrophobicity. Additionally, the sludge floc size average value was reduced from 42.2 μm in run I to 24.6 μm in run II, which led to a significant enhancement in the sludge settleability. As a result, the membrane fouling rate was always less than 3.80 mbar d−1 in run II, whereas in run I these values reached up to 34.7 mbar d−1. These results demonstrated that the electrochemical processes enhanced the mixed liquor filterability. Therefore, their implementation represents a great alternative to improve the operational stability of membrane bioreactors.

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