Changes in mixed liquor and organic foulant properties affect membrane fouling for non-nitrifying and nitrifying biological conditions.
A submerged membrane bioreactor treated settled municipal wastewater at a non-nitrifying solids retention time (SRT) condition (2 days) and a nitrifying SRT condition (10 days), to determine the effect of nitrification on mixed liquor properties and membrane fouling. Membrane fouling rates were almost 10 times greater at the 2-day SRT compared with the 10-day SRT, and results showed increased concentrations of high-molecular-weight organic molecules at the 2-day SRT. The Fourier transform infrared spectroscopy (FTIR) results of the fouled membrane from the 2-day SRT exhibited strong peaks for carbohydrates, while the fouled membrane from the 10-day SRT did not. This is consistent with the fact that, although the total carbohydrate soluble microbial product concentration was highest at the 10-day SRT, the carbohydrate consisted of mostly low-molecular-weight (< 1 kDa) molecules, and 97% of this carbohydrate passed through the membrane at the 10-day SRT.
Trussel
R Shane
RS
Trussell Technologies, Inc., 232 North Lake Ave., Suite 300, Pasadena, CA 91101, USA. shane@trusselltech.com
Jang
Namjung
N
Merlo
Rion P
RP
Kim
In S
IS
Hermanowicz
Slawomir W
SW
Jenkins
David
D
D008567:Membranes, Artificial; D008970:Molecular Weight; D009573:Nitrites / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
D008567:Membranes, Artificial; D009573:Nitrites