TY - JOUR
T1 - Membrane Concentrate Recirculation to Activated Sludge
T2 - Balancing Organic Micropollutant Removal and Salt Retention
AU - Wendt, Hans David
AU - Jonkers, Wendy A.
AU - Kemperman, Antoine J.B.
AU - Langenhoff, Alette A.M.
AU - Lammertink, Rob G.H.
AU - van der Meer, Walter G.J.
AU - de Vos, Wiebe M.
PY - 2025/1/10
Y1 - 2025/1/10
N2 - Current wastewater treatment plants have not been designed to remove organic micropollutants (OMPs) that are now prevalent in surface waters. This desktop study investigates the Membrane Concentrate Recirculation to Activated Sludge (MCRAS) process, which enhances the removal of the OMP by combining conventional activated sludge treatment with membrane filtration and recirculation of the concentrate back to the activated sludge. The process limits the release of the OMP to the environment and offers an integrated approach for treating the concentrate. Four model OMPs (diclofenac, carbamazepine, ibuprofen, and triclosan) were studied using a mass balance model and literature data, comparing the performance of five membrane types (XLE, NF90, NF270, TFC-SR2, and dNF40). Four removal scenarios were identified based on biodegradation and membrane retention. Notably, with low biodegradation and high membrane retention, OMP removal can be significantly enhanced: diclofenac removal increased from 29 to 72% with an NF270 membrane and up to 97% with XLE or NF90 membranes. However, membrane use also leads to the accumulation of salts, as salts are not biodegradable. This highlights the need for a balance between the OMP and salt retention. Therefore, future membrane development should focus on improving the retention of the OMP while minimizing salt retention.
AB - Current wastewater treatment plants have not been designed to remove organic micropollutants (OMPs) that are now prevalent in surface waters. This desktop study investigates the Membrane Concentrate Recirculation to Activated Sludge (MCRAS) process, which enhances the removal of the OMP by combining conventional activated sludge treatment with membrane filtration and recirculation of the concentrate back to the activated sludge. The process limits the release of the OMP to the environment and offers an integrated approach for treating the concentrate. Four model OMPs (diclofenac, carbamazepine, ibuprofen, and triclosan) were studied using a mass balance model and literature data, comparing the performance of five membrane types (XLE, NF90, NF270, TFC-SR2, and dNF40). Four removal scenarios were identified based on biodegradation and membrane retention. Notably, with low biodegradation and high membrane retention, OMP removal can be significantly enhanced: diclofenac removal increased from 29 to 72% with an NF270 membrane and up to 97% with XLE or NF90 membranes. However, membrane use also leads to the accumulation of salts, as salts are not biodegradable. This highlights the need for a balance between the OMP and salt retention. Therefore, future membrane development should focus on improving the retention of the OMP while minimizing salt retention.
KW - integrated membrane process
KW - membranes
KW - organic micropollutants
KW - wastewater treatment
U2 - 10.1021/acsestwater.4c00841
DO - 10.1021/acsestwater.4c00841
M3 - Article
AN - SCOPUS:85214567384
SN - 2690-0637
VL - 5
SP - 284
EP - 299
JO - ACS ES and T Water
JF - ACS ES and T Water
IS - 1
ER -