TY - JOUR
T1 - A novel forward osmosis reactor assisted with microfiltration for deep thickening waste activated sludge
T2 - performance and implication
AU - Yi, Xiawen
AU - Zhong, Huihui
AU - Xie, Ming
AU - Wang, Xinhua
N1 - Funding Information:
This work was supported by the National Natural Science Foundation of China [grant numbers 51978312]; the Six Major Talent Peaks of Jiangsu Province [grant number 2018-JNHB-014]; and Jiangsu Cooperative Innovation Center of Technology and Material of Water Treatment.
Publisher Copyright:
© 2021 Elsevier Ltd
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2021/5/1
Y1 - 2021/5/1
N2 - Waste activated sludge (WAS) treatment has gained growing interests for its increasingly capacity and high process cost. Sludge thickening is generally the first process of the WAS treatment. However, traditional sludge thickening approach was restrained by large footprint, low thickening efficiency, and tendency of releasing phosphorus. Here, we reported a novel microfiltration (MF) membrane assisting forward osmosis (FO) process (MF-FO) for sludge thickening. The MF-FO reactor achieved a sludge thickening of the mixed liquor suspended solids (MLSS) concentration from approximately 7 to 50 g/L after 10-day operation. More importantly, the effluent quality after FO filtration was superior with total organic carbon (TOC), ammonia nitrogen (NH4+-N), nitrate nitrogen (NO3−-N) and total phosphorus (TP) of 1.94 ± 0.46, 0.02 ± 0.07, 4.55 ± 1.59 and 0.24 ± 0.26 mg/L, respectively. Additionally, the integration of MF membrane successfully controlled the salinity of the MF-FO reactor in a low range of 1.6-3.1 mS/cm, which mitigated the flux decline of FO membrane and thus prolonged the operating time. In this case, the flux decline of FO membrane in the MF-FO reactor was mainly due to the membrane fouling. Furthermore, the fouling layer on the FO membrane surface was a gel layer mainly composed of biofoulants and organic foulants when the MLSS concentration was less than 30 g/L, while it turned to a cake layer when the MLSS concentration exceeded 30 g/L. Results reported here demonstrated that the MF-FO reactor is a promising WAS thickening technology for its excellent thickening performance and high effluent quality of FO membrane.
AB - Waste activated sludge (WAS) treatment has gained growing interests for its increasingly capacity and high process cost. Sludge thickening is generally the first process of the WAS treatment. However, traditional sludge thickening approach was restrained by large footprint, low thickening efficiency, and tendency of releasing phosphorus. Here, we reported a novel microfiltration (MF) membrane assisting forward osmosis (FO) process (MF-FO) for sludge thickening. The MF-FO reactor achieved a sludge thickening of the mixed liquor suspended solids (MLSS) concentration from approximately 7 to 50 g/L after 10-day operation. More importantly, the effluent quality after FO filtration was superior with total organic carbon (TOC), ammonia nitrogen (NH4+-N), nitrate nitrogen (NO3−-N) and total phosphorus (TP) of 1.94 ± 0.46, 0.02 ± 0.07, 4.55 ± 1.59 and 0.24 ± 0.26 mg/L, respectively. Additionally, the integration of MF membrane successfully controlled the salinity of the MF-FO reactor in a low range of 1.6-3.1 mS/cm, which mitigated the flux decline of FO membrane and thus prolonged the operating time. In this case, the flux decline of FO membrane in the MF-FO reactor was mainly due to the membrane fouling. Furthermore, the fouling layer on the FO membrane surface was a gel layer mainly composed of biofoulants and organic foulants when the MLSS concentration was less than 30 g/L, while it turned to a cake layer when the MLSS concentration exceeded 30 g/L. Results reported here demonstrated that the MF-FO reactor is a promising WAS thickening technology for its excellent thickening performance and high effluent quality of FO membrane.
KW - forward osmosis
KW - membrane fouling
KW - microfiltration
KW - sludge thickening
KW - waste activated sludge
UR - http://www.scopus.com/inward/record.url?scp=85102258215&partnerID=8YFLogxK
U2 - 10.1016/j.watres.2021.116998
DO - 10.1016/j.watres.2021.116998
M3 - Article
AN - SCOPUS:85102258215
SN - 0043-1354
VL - 195
JO - Water Research
JF - Water Research
M1 - 116998
ER -