Removal of multiple tetracyclines mixture in hydrogen and oxygen based membrane biofilm reactors

Removal of Multiple Tetracyclines Mixture in Hydrogen and Oxygen Based Membrane Biofilm Reactors Tetracycline antibiotics are broad spectrum antimicrobial compounds used commonly in human and animal treatment and agriculture. In this study, it has been studied the simultaneous removal of trible antibiotic mixture including tetracycline, oxytetracycline and chlortetracycline by using either H2- based MBfR or O2-based MBfR. While H2- MBfR was to remove NO3- and TCs mixture under denitrification conditions, O2-MBfR was to oxidize NH4+ and to degrade TCs mixture under nitrification conditions. Both MBfRs were opereted at gas pressure of 4 psi and HRTs between 1 and 10 hr. From experimental results, removal rates, contaminant' s fluxes and hydrogen and oxygen equivalent fluxes have been computed. After H2-MBfR achieved to the adaptation of microbial activities, while removal rates were obtained to be 93 % for TC, 91 % for OTC and 99 % for CTC at 10 hr, it decreased with decreasing of HRT, 66 % for TC, 69 % for OTC and 91 % for CTC at 5 hr. At HRT of 1 hr, antibiotic removals decreased dramatically to 14 %, 24 %, and 42 %, respectively. On the other hand, the fluxes of TC, OTC and CTC were respectively computed to be 2.23 mg/ m2.d, 2.52 mg/ m2.d and 2.87 mg/ m2.d at 10 hr, respectively. At HRT of 1 hr, antibiotic fluxes were on average 4.08 mg TC/ m2.d for TC, 6.72 mg OTC/ m2.d for OTC and 12.12 mg CTC/ m2.d for CTC. When O2-MBfR was operated at 10 hr, the removal rates were found as 53 % of TC, 55 % of OTC and 71 % of CTC. With decreasing HRT three TCs removal decreased dramatically to 21 %, 37 % and 45 % at 5 hr, and 7 %, 24 % and 32 % at 1 hr, respectively. The fluxes of TC, OTC and CTC were respectively 1.57 mg TC/ m2.d, 1.61 mg OTC/ m2.d and 2.08 mg CTC/ m2.d at 10 hr. The fluxes increased with a decrease in HRT due to increasing the loading rates although the performance deteriorated dramatically. At 1 hr HRT fluxes were on average 1.92 mg TC/ m2.d, 7.08 mg OTC/ m2.d and 9.36 mg CTC / m2.d, respectively. Key words: Membrane Biofilm Reactor, Tetracycline, Oxytetracycline, Chlortetracycline, Removal Flux, Equivalent Flux