Effect of components in activated sludge liquor on membrane fouling in a submerged membrane bioreactor.
By a membrane bioreactor with a settle tank in long-term operation and batch experiments, the effects of flocs, soluble microorganism products (SMPs) and metal ions in activated sludge liquor on membrane fouling were investigated. The results showed that foulants absorbed each other and formed a fouling layer as a "second membrane" influencing the permeability of the membrane. The "gel layer" caused by SMPs and "cake layer" by flocs showed great differences in morphology by analysis of scanning electron microscope and atomic force microscope. The "gel layer" was more compact and of poor permeability. When the membrane flux was 40 L/(m(2) x h), the rate of membrane fouling caused by supernatant (0.011 MPa/h) was greater than that by sludge liquor (0.0063 MPa/h). SMPs played very important roles on membrane fouling. In the bulking sludge, with SMPs increasing, the rate of membrane fouling (0.0132 MPa/h) was faster. While after flocculation of the SMPs, the rate of fouling decreased to 0.0034 MPa/h. Flocs could keep holes in their overlaps. They could alleviate membrane fouling by preventing the SMPs directly attaching on membrane surface.
Yu
Shui-li
SL
School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China.
Zhao
Fang-bo
FB
Zhang
Xiao-hui
XH
Jing
Guo-lin
GL
Zhen
Xiang-hua
XH
D019149:Bioreactors; D005374:Filtration; D008567:Membranes, Artificial; D008855:Microscopy, Electron, Scanning; D008970:Molecular Weight; D012722:Sewage
D008567:Membranes, Artificial; D012722:Sewage