The removal of 15 organic micro-pollutants (OMPs) in synthetic municipal wastewater was investigated in a lab-scale mesophilic anaerobic membrane bioreactor (AnMBR) using ultrafiltration and AnMBR followed by nanofiltration (NF), where powdered activated carbon (PAC) was added to enhance OMPs' removal. No significant effects of OMPs spiking and NF connection on bulk organics removal and biogas production were observed. Amitriptyline, diphenhydramine, fluoxetine, sulfamethoxazole, TDCPP and trimethoprim showed readily biodegradable characteristics with consistent biological removal over 80%. Atrazine, carbamazepine, DEET, Dilantin, primidone and TCEP showed refractory characteristics with biological removal below 40%. Acetaminophen, atenolol and caffeine showed a prolonged adaption time around 45 d, initially biological removal below 40% and up to 50–80% after this period. Most readily biodegradable OMPs contained strong electron donating group. Most refractory OMPs contained strong electron withdrawing group or halogen substitute. NF showed consistent high rejection of 80–92% with average of 87% for all OMPs, which resulted in higher OMPs' removal in AnMBR-NF than in AnMBR alone, especially for refractory OMPs. Limited sorption performance of PAC for OMPs' removal was mainly due to low and batch dosage (100 mg/L) as well as the competitive sorption caused by bulk organics.
- anaerobic membrane bioreactor
- electron donating/withdrawing group
- municipal wastewater
- organic micro-pollutants
- First received 26 August 2015.
- Accepted in revised form 14 October 2015.
- © IWA Publishing 2015