scholarly journals Correlation Between Fouling Propensity of Soluble Extracellular Polymeric Substances, Removal Efficiencies and Sludge Metabolic Activity Altered by Different Stress Conditions. Influence of Sludge Retention Time

2012 ◽  
Vol 44 ◽  
pp. 1127-1131
Author(s):  
M. Villain ◽  
B. Marrot
Keyword(s):  
Metabolic Activity ◽  
Retention Time ◽  
Extracellular Polymeric Substances ◽  
Stress Conditions ◽  
Sludge Retention Time ◽  
Removal Efficiencies

Effect of sludge retention time on membrane bio-fouling using different type and pore size of membranes in a submerged membrane bioreactor

2013 ◽  
Vol 67 (3) ◽  
pp. 604-611 ◽  
Author(s):  
Nadir Dizge ◽  
Derya Y. Koseoglu-Imer ◽  
Ahmet Karagunduz ◽  
Bulent Keskinler
Keyword(s):  
Steady State ◽  
Retention Time ◽  
Membrane Fouling ◽  
Extracellular Polymeric Substances ◽  
Organic Loading Rate ◽  
Submerged Membrane Bioreactor ◽  
Sludge Retention Time ◽  
Carbohydrate Concentration ◽  
Activated Sludge Reactor ◽  
Microfiltration Membranes

The objective of this study was to investigate the influence of sludge retention time (SRT) on membrane bio-fouling. An activated sludge reactor was operated at three different SRTs (10, 30, and 50 days). Submerged membrane experiments were performed when the mixed liquor suspended solids (MLSS) concentration reached the steady state conditions. MLSS concentrations reached the steady state at 3,109 ± 194, 6,209 ± 123 and 6,609 ± 280 mg/L for SRTs of 10, 30 and 50 days, respectively. The total soluble microbial products (SMP) were 20.1 ± 3.7, 16.2 ± 7.2 and 28.2 ± 8.4 mg/L at SRTs of 10, 30, and 50 days, respectively. The carbohydrate concentration in the supernatant was about two times more for SRT of 10 days than that for 50 days. The total amount of extracellular polymeric substances (EPS) extracted from the flocs were approximately 74.9 ± 11.9, 67.8 ± 15.0 and 67.5 ± 17.4 mg/g MLSS at three SRTs (10, 30, and 50 days) under the same organic loading rate. The viscosity of the biomass increased with the increasing SRT. The results of flux stepping tests showed that the membrane fouling at SRT 10 days was always higher than that of 30 and 50 days. Four different microfiltration membranes (cellulose acetate, polyethersulfone, mixed ester, and polycarbonate) with three different pore sizes (0.45, 0.22, 0.10 μm) were tested. Filtration resistances were determined for each membrane. Cake resistance was observed to be the most significant fouling mechanism for all membranes.

Effects of Sludge Retention Time on the Characteristics of Mixed Liquor and Membrane Fouling in Membrane Bioreactor

2010 ◽  
Vol 113-116 ◽  
pp. 2057-2061 ◽  
Author(s):  
Zhan Ping Cao ◽  
Jing Li Zhang ◽  
Hong Wei Zhang
Keyword(s):  
Zeta Potential ◽  
Retention Time ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Extracellular Polymeric Substances ◽  
Municipal Wastewater ◽  
Volume Index ◽  
Bacterial Surface ◽  
Sludge Retention Time ◽  
Dominant Bacteria

In the membrane bioreactor (MBR) treating municipal wastewater, the effect of sludge retention time (SRT) on the contents of the extracellular polymeric substances (EPS), tightly bound EPS (TB) and loosely bound EPS (LB) and the ratios of protein and polysaccharide in TB and LB was studied. With the extension of SRT the EPS increased and the ratios of protein and polysaccharide in TB and LB changed. The above changes influenced the charge distribution of bacterial surface, increased the proportion of hydrophilicity and hydrophobicity on the bacterial surface, changed the bacteria from the instable (R-type) to the stable (S-type), decreased the Zeta potential and increased the values of sludge volume index (SVI). The correlation analysis for the main parameters of fouling resistance was performed by SPSS software, and it was found that the correlation coefficient (rp) was -0.818 for Zeta potential, 0.853 for the content of suspended solids in supernatant and 0.832 for relative hydrophobicity, respectively. SRT of the MBR should be controlled below 120 times of the minimum generation-time of dominant bacteria considering the membrane fouling and sludge characteristics.

Impact of sludge retention time on MBR fouling: role of extracellular polymeric substances determined through membrane autopsy

Biofouling ◽  
2017 ◽  
Vol 33 (7) ◽  
pp. 556-566 ◽  
Author(s):  
Ana F. Silva ◽  
Silvia Antunes ◽  
Filomena Freitas ◽  
Gilda Carvalho ◽  
Maria A. M. Reis ◽  
...  
Keyword(s):  
Retention Time ◽  
Extracellular Polymeric Substances ◽  
Sludge Retention Time

scholarly journals Sludge retention time impacts on polyhydroxyalkanoate productivity in uncoupled storage/growth processes

2021 ◽  
pp. 149363
Author(s):  
Mariana Matos ◽  
Rafaela A.P. Cruz ◽  
Pedro Cardoso ◽  
Fernando Silva ◽  
Elisabete B. Freitas ◽  
...  
Keyword(s):  
Retention Time ◽  
Growth Processes ◽  
Sludge Retention Time

Effect of 200 days' sludge retention time on performance of a pilot scale submerged membrane bioreactor for high strength industrial wastewater treatment

2006 ◽  
Vol 53 (11) ◽  
pp. 269-276 ◽  
Author(s):  
C.T. Hay ◽  
D.D. Sun ◽  
S.L. Khor ◽  
J.O. Leckie
Keyword(s):  
Retention Time ◽  
Industrial Wastewater ◽  
Membrane Bioreactor ◽  
Hydraulic Retention Time ◽  
High Strength ◽  
Pilot Scale ◽  
Submerged Membrane Bioreactor ◽  
Sludge Retention Time ◽  
Organic Removal ◽  
Sludge Concentration

A high strength industrial wastewater was treated using a pilot scale submerged membrane bioreactor (MBR) at a sludge retention time (SRT) of 200 d. The MBR was operated at a high sludge concentration of 20 g/L and a low F/M ratio of 0.11 during 300 d of operation. It was found that the MBR could achieve COD and TOC overall removal efficiencies at more than 99 and 98% TN removal. The turbidity of the permeate was consistently in the range of 0.123 to 0.136 NTU and colour254 absorbance readings varied from 0.0912 to 0.0962 a.u. cm−1. The sludge concentration was inversely proportional to the hydraulic retention time (HRT), yielded excellent organic removal and extremely low sludge production (0.0016 kgVSS/day).

Effects of sulfate concentration and sludge retention time on the interaction between methane production and sulfate reduction for butyrate

1994 ◽  
Vol 30 (8) ◽  
pp. 45-54 ◽  
Author(s):  
O. Mizuno ◽  
Y. Y. Li ◽  
T. Noike
Keyword(s):  
Sulfate Reduction ◽  
Retention Time ◽  
Methane Production ◽  
Electron Flow ◽  
Degradation Pathway ◽  
Sulfate Concentration ◽  
High Concentration ◽  
Total Electron ◽  
Sludge Retention Time ◽  
Wide Range

The effects of sulfate concentration and COD/S ratio on the anaerobic degradation of butyrate were investigated by using 2.0 L anaerobic chemostat-type reactor at 35°C. The study was conducted over a wide range of the COD/S ratio (1.5 to 148) by varying COD concentrations (2500–10000 mg/L) and sulfate concentrations (68–1667 mg-S/L) in the substrate. The sludge retention time at each COD/S ratio was changed from 5 to 20 days. The interaction between methane producing bacteria (MPB) and sulfate-reducing bacteria (SRB) was evidently influenced by COD/S ratio in the substrate. When COD/S ratio was 6.0 or more, methane production was the predominate reaction and over 80% of the total electron flow was used by MPB. At the COD/S ratio of 1.5, SRB utilzed over 50% of the total electron flow. A large amount of sulfate reduction resulted in not only the decrease of methane production, but also the rapid increase of the bacterial growth. The degradation pathway of butyrate and the composition of bacterial populations in the reactor were also dominated by COD/S ratio. In sulfate depleted condition, butyrate was degraded to methane via acetate and hydrogen by MPB. On the other hand, butyrate was firstly degraded into sulfide and acetate in sulfate rich conditions by SRB, and the produced acetate was then degraded by acetate consuming MPB and SRB. The methanogenesis from acetate was inhibited by the high concentration of sulfide.

scholarly journals The effect of sludge retention time (SRT) on the Nitrifier typical kinetics at ambient temperature under the low ammonia density

2021 ◽  
Author(s):  
Yifan Li ◽  
Jinzhu Wu ◽  
Yongjie Liu ◽  
Feiyong Chen ◽  
Jie Guan ◽  
...  
Keyword(s):  
Growth Rate ◽  
Ambient Temperature ◽  
Retention Time ◽  
Stable State ◽  
Species Structure ◽  
Maximum Reaction Rate ◽  
Sludge Retention Time ◽  
Structure Changes ◽  
Nitrification Process ◽  
D 20

Abstract Sludge retention time (SRT) regulation is one of the essential management techniques for refined control of the main-sidestream treatment process under the low ammonia density. It is indispensable to understand the effect of SRTs changes on the Nitrifier kinetics to obtain the functional separation of the Nitrifier and the refined control of the nitrification process. In this study, Nitrifier was cultured with conditions of 35 ± 0.5 °C, pH 7.5 ± 0.2, DO 5.0 ± 0.5 mg-O/L, and SRTs was controlled for 40 d, 20 d, 10 d, and 5 d. The net growth rate (), decay rate (), specific growth rate (), the yield of the Nitrifier (), temperature parameter (), and inhibition coefficient () have been measured and extended with the SRT decreases. Instead, the half-saturation coefficient () decreased. In addition, the limited value of pH inhibition occurs (), and the pH of keeping 5% maximum reaction rate () was in a relatively stable state. The trade of kinetics may be induced by the species structure of Nitrifier changed. The Nitrosomonas proportion was increased, and the Nitrospira used to be contrary with the SRT decreasing. It is a match for the functional separation of Nitrifier when SRTs was 20 d at ambient temperature under the low ammonia density. The kinetics of ammonia-oxidizing organism (AOO) and nitrite-oxidizing organism (NOO) in Nitrifier under different SRT conditions should be measured respectively to the refined control of the partial nitrification process in the future study. HIGHLIGHT The Nitrifier typical kinetics used to be affected notably by way of SRTs changes. The species structure of the Nitrifier was recognized beneath distinctive SRTs. The change of Nitrifier kinetics with SRTs used to be estimated by the species structure changes.

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