TY - JOUR
T1 - Perspectives of coagulation/flocculation for the removal of pharmaceuticals from domestic wastewater
T2 - A critical view at experimental procedures
AU - Kooijman, G.
AU - de Kreuk, M. K.
AU - Houtman, C.
AU - van Lier, J. B.
N1 - Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.
PY - 2020
Y1 - 2020
N2 - Literature frequently reports that colloids in aqueous matrices sorb a large fraction of pharmaceuticals. Since coagulation/flocculation removes colloids, it is expected that coagulation/flocculation in principle should be useful in concentrating pharmaceuticals in wastewater treatment, which would facilitate the treatment of these refractory compounds. In our present work, we researched the potential of coagulation/flocculation for removing pharmaceuticals from raw sewage. Results from jar tests showed that pharmaceuticals are hardly removed from sewage with coagulation/flocculation. To investigate the discrepancy between reported colloidal sorption and the lack of removal when removing colloids, we tested a commonly applied experimental setup, which makes use of ultra-filtration (UF), for determining the colloidal sorption of pharmaceuticals. The UF method under research was compared with an assessment making use of flocculation. Both methods, UF and flocculation, showed similar removal of colloids. However, during UF, the retention of pharmaceuticals reached values up to 93 ± 4 %. In contrast, when removing the colloids with flocculation, no pharmaceutical removal was observed. These results confirm that it is very likely to introduce an analysis bias in using UF membranes in the determination of colloidal sorption of pharmaceuticals. In fact, results predict an over-estimation caused by a direct retention of pharmaceuticals without any binding to colloidal matter. Overall results of the current work show that pharmaceuticals hardly sorb to colloids and herewith the absence of removal of pharmaceuticals during coagulation/flocculation is explained.
AB - Literature frequently reports that colloids in aqueous matrices sorb a large fraction of pharmaceuticals. Since coagulation/flocculation removes colloids, it is expected that coagulation/flocculation in principle should be useful in concentrating pharmaceuticals in wastewater treatment, which would facilitate the treatment of these refractory compounds. In our present work, we researched the potential of coagulation/flocculation for removing pharmaceuticals from raw sewage. Results from jar tests showed that pharmaceuticals are hardly removed from sewage with coagulation/flocculation. To investigate the discrepancy between reported colloidal sorption and the lack of removal when removing colloids, we tested a commonly applied experimental setup, which makes use of ultra-filtration (UF), for determining the colloidal sorption of pharmaceuticals. The UF method under research was compared with an assessment making use of flocculation. Both methods, UF and flocculation, showed similar removal of colloids. However, during UF, the retention of pharmaceuticals reached values up to 93 ± 4 %. In contrast, when removing the colloids with flocculation, no pharmaceutical removal was observed. These results confirm that it is very likely to introduce an analysis bias in using UF membranes in the determination of colloidal sorption of pharmaceuticals. In fact, results predict an over-estimation caused by a direct retention of pharmaceuticals without any binding to colloidal matter. Overall results of the current work show that pharmaceuticals hardly sorb to colloids and herewith the absence of removal of pharmaceuticals during coagulation/flocculation is explained.
KW - Colloids
KW - Filtration
KW - Pharmaceutical
KW - Sorption
KW - Wastewater
UR - http://www.scopus.com/inward/record.url?scp=85078842340&partnerID=8YFLogxK
U2 - 10.1016/j.jwpe.2020.101161
DO - 10.1016/j.jwpe.2020.101161
M3 - Article
AN - SCOPUS:85078842340
SN - 2214-7144
VL - 34
JO - Journal of Water Process Engineering
JF - Journal of Water Process Engineering
M1 - 101161
ER -