Performance of a hybrid system for antibiotic wastewater treatment

Abstract

A hybrid anaerobic/aerobic moving bed biofilm reactor (A/O MBBR) system was established for wastewater treatment which contained tetracycline (TC) at the "mu g/L" level. The pilot-scale system was contained an 11.87 L anaerobic unit, a 32.29 L aerobic unit and a 21.53 L secondary sedimentation tank. Results for the single-factor experiment showed that the optimal temperature for this A/O MBBR was 25 degrees C with chemical oxygen demand (COD) and NH4+-N removal rate at 85.71% +/- 0.94% and 90.46% +/- 1.45%, respectively. Otherwise, the A/O MBBR system showed a high organic load that when the influent COD concentration was about 450 mg/L, the removal efficiency of COD and NH4+-N was 84.51% +/- 1.23% and 81.24% +/- 1.35% respectively, with effluent concentration of 71.94 +/- 5.18 and 7.24 +/- 0.63 mg/L respectively. The highest TC removal efficiency occurred at an influent concentration of 50 mu g/L under 8 h of hydraulic retention time, and the average degradation rate during this phase was 50.03% +/- 1.67%. In addition, the highest TC removal amount was 73.40 mu g/L occurred at a fourth phase when the initial concentration of TC was 206.46 mu g/L, showing the desired performance than many existed municipal sewage treatment plants. Moreover, this research provides a case study of a pilot-scale model for TC wastewater biodegradation and practical application.