YANG Ying-ming,WANG Xu-dong,LIU Xuan-ning,et al.Effect of EDTA-2Na Draw Solute on Operating Performance of Forward Osmosis MBR[J].China Water & Wastewater,2021,37(11 11):9-16.
Effect of EDTA-2Na Draw Solute on Operating Performance of Forward Osmosis MBR
China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU]
volume:
第37卷
Number:
11 11
Page:
9-16
Column:
Date of publication:
2021-06-01
- Keywords:
- forward osmosis; membrane bioreactor; EDTA-2Na; membrane fouling
- Abstract:
- A forward osmosis (FO) membrane bioreactor (MBR) was operated by using ethylene-diamine-tetra acetic acid disodium salt (EDTA-2Na) as the draw solute, and its operating performance and membrane fouling were investigated and compared with another MBR with NaCl as the draw solute. Compared with NaCl, EDTA-2Na serving as the draw solute could effectively reduce the salt accumulation in the bioreactor and obtain a higher water flux. When the MBR was operated with two kinds of draw solute (EDTA-2Na and NaCl), the removal efficiency of pollutants was similar, which was independent of the type of draw solute. The removal rates of TOC, TN, ammonia nitrogen and TP by the forward osmosis MBR were 94.6%, 71.7%, 96.8% and 99.2%, respectively. The decrease of water flux would lead to the decrease of MLSS and MLVSS. When EDTA-2Na was used as the draw solute in the forward osmosis MBR, the increase of EDTA concentration in the bioreactor led to the increase of extracellular polymer (EPS) concentration, which aggravated the fouling of FO membrane. The results of FTIR, SEM and EDS showed that the active layer of the FO membranes was covered by a cake layer when the forward osmosis MBR was operated with two kinds of draw solute (EDTA-2Na and NaCl). There were more organic foulants and less inorganic precipitation on the polluted membrane surfaces of the forward osmosis MBR with EDTA-2Na as the draw solute.
Last Update:
2021-06-01