Effects of mixed liquor pH on membrane fouling and micro-pollutant removals in membrane bioreactors for municipal landfill leachate treatment.
This research investigated the membrane fouling and micro-pollutant removals in treatment of municipal landfill leachate at various pH levels (i.e. 5.5, 6.5, 7.5, and 8.5) using membrane bioreactors. The findings revealed that membrane fouling was influenced by the pH level of mixed liquor, with pH 5.5 exhibiting the most severe membrane fouling. At pH 5.5, proteins and carbohydrates were predominant in the membrane foulants, while at pH 8.5 humic-like and inorganic substances constituted the largest proportion of the foulants on the membrane surface. The removal efficiencies of micro-pollutants (bisphenol-A; 2,6-di-tert-butylphenol and 2,6-di-tert-butyl-4-methylbutylphenol) were nevertheless insignificantly influenced by the pH levels of mixed liquor. In addition, the removal rates of the compounds at pH 5.5 were slightly lower vis-à-vis at the higher pH levels. The micro-pollutant retention on the fouled membranes was also significant and highest under the mixed liquor pH of 8.5. Furthermore, the experiments demonstrated that the varying degrees of rejection by the fouled membranes could be attributed to the alteration of foulant characteristics as a result of the pH variations.
Department of Environmental Engineering, Faculty of Engineering, Kasetsart University, Bangkok 10900 and MTEC, National Science and Technology Development Agency (NSTDA), Pathumthani 12120, Thailand.
Samunya
S
Sanguanpak
Department of Environmental Engineering, Faculty of Engineering, Kasetsart University, Bangkok 10900, Thailand E-mail: fengccc@ku.ac.th.
Chart
C
Chiemchaisri
Department of Environmental Engineering, Faculty of Engineering, Kasetsart University, Bangkok 10900, Thailand E-mail: fengccc@ku.ac.th.
Wilai
W
Chiemchaisri
Environmental Science Center, University of Tokyo, Tokyo 113, Japan.
Kazuo
K
Yamamoto
D001559:Benzhydryl Compounds / Q000302:isolation & purification; D019149:Bioreactors; D006863:Hydrogen-Ion Concentration; D008567:Membranes, Artificial; D010636:Phenols / Q000302:isolation & purification; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification; D000098826:Bisphenol A Compounds
D001559:Benzhydryl Compounds; D008567:Membranes, Artificial; D010636:Phenols; D062065:Wastewater; D014874:Water Pollutants, Chemical; C035407:2,6-di-tert-butylphenol; C006780:bisphenol A; D000098826:Bisphenol A Compounds