Fouling potential of lipopolysaccharides released at low temperatures in MBRs

2020 ◽  
Vol 81 (3) ◽  
pp. 529-534
Author(s):  
T. Kakuda ◽  
H. Iwasaki ◽  
K. Kimura
Keyword(s):  
Membrane Fouling ◽  
Low Temperatures ◽  
Municipal Wastewater ◽  
Pilot Scale ◽  
Synthetic Wastewater ◽  
Efficient Operation ◽  
Term Operation ◽  
Key Factor ◽  
The Impact

Abstract Sludge filterability in membrane bioreactors (MBRs) fluctuates and affects membrane fouling. Therefore, understanding the reasons for the fluctuations of sludge filterability is important for the efficient operation of MBRs. In this study, a pilot-scale MBR treating municipal wastewater was operated for about 600 days and the variations in sludge filterability were continuously monitored by batch-filtration experiments using the same membranes as in the MBR. To investigate the reasons for the deterioration of sludge filterability, constituents in sludge supernatant were intensively monitored, and the correlations with sludge filterability were determined. The concentration of lipopolysaccharides (LPS) in sludge supernatant exhibited significantly higher correlation with sludge filterability than did conventional indexes (i.e. polysaccharides and proteins). Size fractions affecting MBR sludge filterability were also investigated, and it was suggested that colloidal LPS deteriorated MBR sludge filterability. Based on the long-term operation of the MBR, increase in colloidal LPS under low temperatures of the mixed liquor suspension was a key factor in the deterioration of sludge filterability. The impact of LPS increasing under low temperatures should be investigated by operating bench-scale MBRs fed with synthetic wastewater in controlled conditions.

Performance of membrane bioreactor combined with pre-coagulation/sedimentation

2004 ◽  
Vol 4 (1) ◽  
pp. 143-149 ◽  
Author(s):  
T. Itonaga ◽  
Y. Watanabe
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Suspended Solids ◽  
Extracellular Polymeric Substances ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Municipal Wastewater Treatment ◽  
Term Operation ◽  
Made In

This paper deals with the performance of a hybrid membrane bioreactor (MBR) combined with pre-coagulation/sedimentation. Primary clarifier effluent in a municipal wastewater treatment plant was fed into the hybrid MBR to investigate its performance during long-term operation. Pre-coagulation/sedimentation process efficiently removed the suspended solids including organic matter and phosphorus. Comparison of the hybrid MBR and conventional MBR was made in terms of the permeate quality and membrane fouling. As the organic loading to the MBR was significantly reduced by the pre-coagulation/sedimentation, production and accumulation of extracellular polymeric substances (EPS) may be limited. Therefore, the mixed liquor viscosity in the hybrid MBR was much lower than that in the conventional MBR. These effect caused by pre-coagulation/sedimentation brought a remarkable improvement in both permeate quality and membrane permeability.

scholarly journals Reactor performance and membrane fouling of a novel submerged aerobic granular sludge membrane bioreactor during long-term operation

2017 ◽  
Vol 9 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Jianfeng Li ◽  
Yanjun Liu ◽  
Xiaoning Li ◽  
Fangqin Cheng
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Sewage Treatment ◽  
Granular Sludge ◽  
Synthetic Wastewater ◽  
Aerobic Granular Sludge ◽  
Municipal Sewage ◽  
Reactor Performance ◽  
Term Operation

Abstract The aerobic granular sludge membrane bioreactor (AGS-MBR) has the potential for simultaneous carbon/nitrogen removal and membrane fouling mitigation. Most studies have focused on comparison of granular sludge MBR and flocculent sludge MBR in short-term tests using synthetic wastewater. In this study, two identical AGS-MBRs were developed, and the reactor performance and membrane fouling were examined systemically over 120 days for synthetic wastewater and municipal sewage treatment, respectively. Results showed that regular granules with good settling ability were developed and maintained throughout the experimental period. Regardless of the substrate type, AGS-MBR demonstrated a stable removal of carbon (85–95%) and nitrogen (50–55%) in long-term operation. In addition, the membrane fouling propensity is apparently lower in AGS-MBRs with no membrane cleaning for 4 months at a flux of 20 L m−2h−1. The filtration resistance analysis indicates that the main membrane resistance was caused by irreversible fouling in both of the reactors. Membrane foulant analysis indicates that proteins in extracellular polymeric substances are more prone to be attached by the membrane of AGS-MBRs because of their hydrophobic nature. This study shows that AGS-MBR is effective and stable for municipal sewage treatment and reuse during long-term operation.

Long term operation of pilot-scale biological nutrient removal process in treating municipal wastewater

2009 ◽  
Vol 100 (13) ◽  
pp. 3180-3184 ◽  
Author(s):  
Daekeun Kim ◽  
Keum-Yong Kim ◽  
Hong-Duck Ryu ◽  
Kyung-Kook Min ◽  
Sang-Ill Lee
Keyword(s):  
Nutrient Removal ◽  
Municipal Wastewater ◽  
Pilot Scale ◽  
Biological Nutrient Removal ◽  
Term Operation ◽  
Removal Process

Designing a CRM Framework for online & offline sports footwear retailers

2015 ◽  
Vol 3 (1) ◽  
Author(s):  
Rodrigo Cueva ◽  
Guillem Rufian ◽  
Maria Gabriela Valdes
Keyword(s):  
Environmental Changes ◽  
Customer Relationship ◽  
Business Strategies ◽  
Economic Sectors ◽  
Running Shoes ◽  
Brick And Mortar ◽  
Key Factor ◽  
On Line ◽  
The Impact

The use of Customer Relationship Managers to foster customers loyalty has become one of the most common business strategies in the past years.  However, CRM solutions do not fill the abundance of happily ever-after relationships that business needs, and each client’s perception is different in the buying process.  Therefore, the experience must be precise, in order to extend the loyalty period of a customer as much as possible. One of the economic sectors in which CRM’s have improved this experience is retailing, where the personalized attention to the customer is a key factor.  However, brick and mortar experiences are not enough to be aware in how environmental changes could affect the industry trends in the long term.  A base unified theoretical framework must be taken into consideration, in order to develop an adaptable model for constructing or implementing CRMs into companies. Thanks to this approximation, the information is complemented, and the outcome will increment the quality in any Marketing/Sales initiative. The goal of this article is to explore the different factors grouped by three main domains within the impact of service quality, from a consumer’s perspective, in both on-line and off-line retailing sector.  Secondly, we plan to go a step further and extract base guidelines about previous analysis for designing CRM’s solutions focused on the loyalty of the customers for a specific retailing sector and its product: Sports Running Shoes.

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