TY - JOUR
T1 - Removal of inorganic charged micropollutants in an ion-exchange membrane bioreactor
AU - Velizarov, Svetlozar
AU - Matos, Cristina
AU - Reis, Maria A. M.
AU - Crespo, João
N1 - The authors acknowledge the financial support from the Fundaggo para a Ci~ncia e Tecnologia (FCT), Lisbon, Portugal, to this study through research projects POCTI/BIO/43625/2000 and POCTI/EQU/39482/2001. C. Matos is a PhD student with a grant SFRH/BD/9087/2002 from FCT. The authors would like to acknowledge the careful experimental assistance of G. Meyen, B. Orzechowska and Dr. R. Viegas in the transport characterization of the ion-exchange membranes.
PY - 2005/7/10
Y1 - 2005/7/10
N2 - The transport of anionic drinking water micropollutants-perchlorate, nitrate and arsenate as well as that of a cationic micropollutant ionic mercury-through selected commercial ion-exchange membranes was studied under Donnan dialysis conditions in order to evaluate the possibility of using these membranes for pollutant removal in an ion-exchange membrane bioreactor (IEMB). The anion-exchange membrane, Neosepta ACS, proved to be a good choice for perchlorate and nitrate but was not suitable for arsenate, for which the Ionac MA-3475 allowed more than a three-order magnitude increase in flux. The cation-exchange membrane, Nafion-112, showed promising results for the transport of mercuric ions, while the Neosepta CMX was almost impermeable to this micropollutant. Tap water from the Lisbon public distribution network was supplemented with 100 ppb of perchlorate and 60 ppm of nitrate and was continuously treated in the IEMB incorporating a Neosepta ACS membrane for a period of about 2 months. Highly selective simultaneous removal of both pollutants was observed, in spite of their very different concentrations in the contaminated water. Secondary pollution of the treated water by microbial cells and residual organics was not found. Since the nitrate concentration in the treated water stream (<1 ppm) was always much lower than the EU recommended one of 25 ppm, the amount of water that can be treated in the system was dependent of the desired degree of removal of perchlorate, for which the US EPA suggests an acceptable concentration range from 4 to 18 ppb. The water treatment rate was about 3 L/(m2h) when the objective was to achieve 4 ppb in the treated effluent (96% removal) but increased to 18 L/(m2h) when the treated water contained the upper suggested limit of 18 ppb of perchlorate (82% removal).
AB - The transport of anionic drinking water micropollutants-perchlorate, nitrate and arsenate as well as that of a cationic micropollutant ionic mercury-through selected commercial ion-exchange membranes was studied under Donnan dialysis conditions in order to evaluate the possibility of using these membranes for pollutant removal in an ion-exchange membrane bioreactor (IEMB). The anion-exchange membrane, Neosepta ACS, proved to be a good choice for perchlorate and nitrate but was not suitable for arsenate, for which the Ionac MA-3475 allowed more than a three-order magnitude increase in flux. The cation-exchange membrane, Nafion-112, showed promising results for the transport of mercuric ions, while the Neosepta CMX was almost impermeable to this micropollutant. Tap water from the Lisbon public distribution network was supplemented with 100 ppb of perchlorate and 60 ppm of nitrate and was continuously treated in the IEMB incorporating a Neosepta ACS membrane for a period of about 2 months. Highly selective simultaneous removal of both pollutants was observed, in spite of their very different concentrations in the contaminated water. Secondary pollution of the treated water by microbial cells and residual organics was not found. Since the nitrate concentration in the treated water stream (<1 ppm) was always much lower than the EU recommended one of 25 ppm, the amount of water that can be treated in the system was dependent of the desired degree of removal of perchlorate, for which the US EPA suggests an acceptable concentration range from 4 to 18 ppb. The water treatment rate was about 3 L/(m2h) when the objective was to achieve 4 ppb in the treated effluent (96% removal) but increased to 18 L/(m2h) when the treated water contained the upper suggested limit of 18 ppb of perchlorate (82% removal).
KW - Donnan dialysis
KW - Drinking water
KW - Ion-exchange membrane bioreactor
KW - Ionic micropollutants
UR - http://www.scopus.com/inward/record.url?scp=27644538942&partnerID=8YFLogxK
U2 - 10.1016/j.desal.2004.11.037
DO - 10.1016/j.desal.2004.11.037
M3 - Article
AN - SCOPUS:27644538942
VL - 178
SP - 203
EP - 210
JO - Desalination
JF - Desalination
SN - 0011-9164
IS - 1-3(SI)
T2 - Conference on Membranes in Drinking and Industrial Water Production
Y2 - 15 November 2004 through 17 November 2004
ER -