The Influence of Modified Membrane Bio-reactor System on Ultra-filtration Membrane Fouling
Date Issued
2010
Date
2010
Author(s)
You, Li-Yuan
Abstract
Membrane bio-reactor (MBR) is the most popular biological treatment process because of its high mixed liquid suspended solid (MLSS), low production of sludge, stable and good effluent water, and a smaller footprint. However, membrane fouling has been the major problem that limiting the wide applications of MBR.
High sludge concentration of conventional MBR is referred as one of the major reason of membrane fouling. The fixed carrier biological system (FCBS) with longer sludge retention time (SRT) and low suspended solid (SS) believed to enable less membrane fouling. Thus, the influence of modified MBR system by combining FCBS with ultra-filtration membrane module on membrane fouling at various operating parameters such as HRT (18, 12 and 6h), continuous and interrupted aeration (1h aeration-1h non-aeration and 1h aeration-2h non-aeration) at room temperature was investigated and industrial wastewater was used throughout the experiment.
The result shows that HRT and aeration significantly influence the MBR performance. The shorter HRT (6h) with interrupted aeration results the lower COD (initial: 458~1007 mg/L) and NH+4-N (initial 6.3~12.8 mg/L) removal with higher membrane fouling. Whereas with continuous aeration at higher HRT (18h) higher removals of COD, NH+4-N and low effluent SS of 92.5 %, 93.7 % and 30.6 mg/L was achieved respectively and also results in less membrane fouling. The membrane fouling experiments at constant flux of 20 LMH, HRT of 12 h with continuous aeration shows that a maximum trans-membrane pressure (TMP) of 55 kpa was reached in 215 min which is 3.8 times delayed than the conventional MBR. From the results the best performance of the reactor operating conditions were found to be in the order of 18h>12h>6h HRTs and continuous aeration > interrupted aeration.
The conclusion it can be confidently stated that the modified MBR system really improve the MBR performance by decreasing fouling in comparison with conventional MBR system. Therefore, modified MBR have the potential for improvement or replacement of the existing conventional activated sludge process with regard to improving the effluent qualities by decreasing membrane fouling.
Subjects
modified MBR
fixed carrier biological system (FCBS)
membrane fouling
Type
thesis
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