Reduction of emerging micropollutants, organic matter, nutrients and salinity from real wastewater by combined MBR–NF/RO treatment

• MBRs (FS and HF) achieved removals of TN >80%, TP >50%, COD >98% and total removal of SS.
• MBR–NF/RO treatment showed removal efficiencies >90% for conductivity, TOC, NO3- and TP.
• ACE, IBP, CAF, NIC, 4-t-OP and BPA were almost completely removed by MBR treatment.
• NF/RO post-treatment improved carbamazepine and diclofenac rejection in particular.
• The main mechanism of EMPs removal in both membranes (NF and RO) was steric hindrance.

To study the possibility of producing better water quality from municipal wastewater, a membrane bioreactor (MBR) pilot plant with flat sheet (FS) and hollow fiber (HF) membranes coupled with another pilot plant equipped with nanofiltration (NF)/reverse osmosis (RO) membranes were operated to treat municipal wastewater from the wastewater treatment plant (WWTP) Rincón de León, Alicante (Spain). This study was focused on improving the quality of the permeate obtained from the MBR process when complemented by NF or RO stages with respect to salinity, organic matter and nutrients. Furthermore, the removal efficiencies of 10 EMPs were evaluated, comparing the reductions achieved between the wastewater treatment by MBR (adsorption to sludge and biodegradation) and the later treatment using NF or RO (mainly size exclusion). The results showed that the high quality of water was obtained which is appropriate for reuse with salinity removal efficiencies higher than 97%, 96% for total organic carbon (TOC), 91% for nitrates NO3- and 99% for total phosphorous (TP). High removal efficiencies were obtained for the majority of the analyzed EMP compounds.