Fate of antibiotics during membrane separation followed by physical-chemical treatment processes

Membrane separation technology has been widely utilised to obtain clean permeate and concentrated nutrients from biogas digested slurry. However, some antibiotics are frequently found in digested slurry. Antibiotic removal during the steps, including paper filtration (PF), hollow-fibremembrane ultrafiltration (HF), nanofiltration (NF) and reverse osmosis (RO), of combined membrane separation processing (CMP) remain poorly understood. Experimentswere performed on a pilot-scale CMP plant to investigate antibiotic transport and rejection efficiencies in CMP products and analyse the antibiotic removal performances of additional treatments. Results showed average relative antibiotic rejection efficiencies of 50%, 83%, 28% and 14% for PF, HF, NF and RO during CMP, respectively. Each CMP product needed additional treatment for antibiotic removal. Antibiotic removal capacity followed the order of fine halloysite > P25 > activated charcoal > coarse halloysite. The average antibiotic removal rates for different CMP products ranged from 73.3% to 99.9%. But antibiotics can only be adsorbed by fine halloysite andmust be degraded through other treatments, Thus, P25 has considerable practical importance for the removal of antibiotics, as antibiotics can be degraded during photocatalysis. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

Membrane separation technology is widely used to obtain clean permeate and concentrated nutrients from biogas digested slurry, but the removal of antibiotics during the steps of combined membrane separation processing remains poorly understood. Experimental results showed different antibiotic rejection efficiencies for different membrane processes, and additional treatments are needed for efficient antibiotic removal. Fine halloysite has good adsorption capacity for antibiotics, while P25 can effectively degrade antibiotics during photocatalysis.