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Mechanism of charged pollutants removal in an ion exchange membrane bioreactor: Drinking water denitrification
Author(s) -
Velizarov Svetlozar,
Rodrigues Carla M.,
Reis Maria A.,
Crespo João G.
Publication year - 2000
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/1097-0290(2000)71:4<245::aid-bit1014>3.0.co;2-f
Subject(s) - membrane bioreactor , pollutant , denitrification , bioreactor , mechanism (biology) , chemistry , environmental chemistry , ion exchange , membrane , environmental science , environmental engineering , ion , nitrogen , biochemistry , organic chemistry , philosophy , epistemology
The mechanism of anionic pollutant removal in an ion exchange membrane bioreactor (IEMB) was studied for drinking water denitrification. This hybrid process combines continuous ion exchange transport (Donnan dialysis) of nitrate and its simultaneous bioreduction to gaseous nitrogen. A nonporous mono‐anion permselective membrane precludes direct contact between the polluted water and the denitrifying culture and prevents secondary pollution of the treated water with dissolved nutrients and metabolic products. Complete denitrification may be achieved without accumulation of NO 3 − and NO 2 − ions in the biocompartment. Focus was given to the effect of the concentration of co‐ions, counterions, and ethanol on the IEMB performance. The nitrate overall mass transfer coefficient in this hybrid process was found to be 2.8 times higher compared to that in a pure Donnan dialysis process without denitrification. Furthermore, by adjusting the ratio of co‐ions between the biocompartment and the polluted water compartment, the magnitude and direction of each individual anion flux can be easily regulated, allowing for flexible process operation and control. Synthetic groundwater containing 135–350 mg NO 3 − L −1 was treated in the IEMB system. A surface denitrification rate of 33 g NO 3 − per square meter of membrane per day was obtained at a nitrate loading rate of 360 g NO 3 − m −3 d −1 , resulting in a nitrate removal efficiency of 85%. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 71: 245–254, 2000/2001.