Mitigation of membrane fouling in a seawater-driven forward osmosis system for waste activated sludge thickening

2019 ◽  
Vol 241 ◽  
pp. 118373 ◽  
Author(s):  
Faqian Sun ◽  
Dan Lu ◽  
Jia Shin Ho ◽  
Tzyy Haur Chong ◽  
Yan Zhou
Keyword(s):  
Activated Sludge ◽  
Membrane Fouling ◽  
Forward Osmosis ◽  
Waste Activated Sludge ◽  
Sludge Thickening

Application of forward osmosis (FO) under ultrasonication on sludge thickening of waste activated sludge

2015 ◽  
Vol 72 (8) ◽  
pp. 1301-1307 ◽  
Author(s):  
Nguyen Cong Nguyen ◽  
Hau Thi Nguyen ◽  
Shiao-Shing Chen ◽  
Nhat Thien Nguyen ◽  
Chi-Wang Li
Keyword(s):  
Activated Sludge ◽  
Hybrid System ◽  
Membrane Fouling ◽  
Water Flux ◽  
Forward Osmosis ◽  
Bound Water ◽  
Feed Solution ◽  
N Removal ◽  
Sludge Thickening ◽  
Sludge Concentration

Forward osmosis (FO) is an emerging process for dewatering solid–liquid stream which has the potential to be innovative and sustainable. However, the applications have still been hindered by low water flux and membrane fouling when activated sludge is used as the feed solution due to bound water from microbial cells. Hence, a novel strategy was designed to increase sludge thickening and reduce membrane fouling in the FO process under ultrasonic condition. The results from the ultrasound/FO hybrid system showed that the sludge concentration reached up to 20,400 and 28,400 mg/L from initial sludge concentrations of 3000 and 8000 mg/L with frequency of 40 kHz after 22 hours, while the system without ultrasound had to spend 26 hours to achieve the same sludge concentration. This identifies that the presence of ultrasound strongly affected sludge structure as well as sludge thickening of the FO process. Furthermore, the ultrasound/FO hybrid system could achieve NH4+-N removal efficiency of 96%, PO43−-P of 98% and dissolved organic carbon (DOC) of 99%. The overall performance demonstrates that the proposed ultrasound/FO system using seawater as a draw solution is promising for sludge thickening application.

Membrane fouling and process performance of forward osmosis membranes on activated sludge

2008 ◽  
Vol 319 (1-2) ◽  
pp. 158-168 ◽  
Author(s):  
E CORNELISSEN ◽  
D HARMSEN ◽  
K DEKORTE ◽  
C RUIKEN ◽  
J QIN ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Membrane Fouling ◽  
Forward Osmosis ◽  
Process Performance

scholarly journals Forward osmosis membrane fouling and cleaning for wastewater reuse

2016 ◽  
Vol 7 (2) ◽  
pp. 111-120 ◽  
Author(s):  
Youngbeom Yu ◽  
Seockheon Lee ◽  
Sung Kyu Maeng
Keyword(s):  
Activated Sludge ◽  
Flow Velocity ◽  
Membrane Fouling ◽  
Suspended Solids ◽  
Wastewater Reuse ◽  
Forward Osmosis ◽  
Cross Flow ◽  
Short Period ◽  
Cross Flow Velocity ◽  
Cleaning Methods

Membrane fouling properties and different physical cleaning methods for forward osmosis (FO) and reverse osmosis (RO) laboratory-scale filtration systems were investigated. The membrane fouling, with respect to flux reduction, was lower in FO than in RO when testing an activated sludge effluent. Cross-flow velocity, air-scouring, osmotic backwashing and effect of a spacer were compared to determine the most effective cleaning method for FO. After a long period of fouling with activated sludge, the flux was fully recovered in a short period of osmotic backwashing compared with cleaning by changing cross-flow velocity and air-scouring. In this study, the osmotic backwashing was found to be the most efficient way to clean the FO membrane. The amount of RNA recovered from FO membranes was about twice that for RO membranes; biofouling could be more significant in FO than in RO. However, the membrane fouling in FO was lower than that in RO. The spacer increased the flux in FO with activated sludge liquor suspended solids of 2,500 mg/L, and there were effects of spacer on performance of FO–MBR membrane fouling. However, further studies are required to determine how the spacer geometry influences on the performance of the FO membrane.

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