Anaerobic/aerobic sequential treatment of chloramphenicole and streptomycin antibiotics using anaerobic baffled and aerobic sludge reactors

In the context of this thesis, treatability of Streptomycin and Chloramphenicole, antibiotics which are toxic and non-degradable were experienced with the increasing dosages of Streptomycin and Chloramphenicole in a sequencing anaerobic baffled reactor (ABR)/aerobic continuous stirred tank reactor (CSTR) system. Furthermore, the effects of decreasing hyraulic residence time (HRT) on the performance of sequencing ABR/CSTR reactor system was investigated. The maximum chemical oxygen demand (COD) removal efficiency was between 89% and 95% at streptomycin concentrations varying between 100 and 200 mg/L in the ABR reactor. The volatile fatty acid (VFA)/ Bicarbonate alkalinity (B. alk.) ratio varied between 0.368 and 0.005 in the ABR effluent indicating the stability of the ABR reactor as the streptomycin concentrations were increased from 0 to 400 mg/L. The maximum methane percentage of the biogas was 53% at a streptomycin concentration of 200 mg/l. For maximum COD removal efficiency (94.5%) the optimum HRT was found as 19.2 days. For the lowest VFA concentration (258 mg/L) the optimum HRT was 9.60 days. The maximum specific methanogenic activity was 0.218 g COD-CH4/ gVSS day for HRTs between 7.68 and 9.60 days. The acute toxicity test results performed with Daphnia magna showed that the EC50 values decreased from influent 400 mg/L to 132 mg/L , and to 20 mg/L in the effluents of ABR , in aerobic reactor effluent at a HRT of 38.4 days. The total acute toxicity reduction in sequential ABR CSTR reactor effluent was 95%. The total maximum streptomycin removal efficiency was 74% in the sequential reactor system at an influent streptomycine concentration of 179.57 mg/L at a HRT of 12.8 days. In this study it was found that the ?streptomycin? antibiotic was mainly degraded (179,57 mg/L) in anaerobic ABR reactor while the remaining small part of this antibiotic (47,54 mg/L) was removed in the aerobic CSTR reactor.The maximum COD removal efficiencies were around 94-96 % for a chloramphenicole concentration of 130 mg/L and around 99% at a chloramphenicole concentration of 50 mg/l. As the chloramphenicole concentration increased from 0 to 340 mg/l the VFA concentrations decreased from 2822 to 1858 mg/L while the VFA/Bİc.Alk. ratios varied between 0,005 and 0,014 in the effluent of ABR. The COD removal efficiency increased from 77,37% to 97% until a chloramphenicole concentration of 130 mg/L. The methane percentages of biogas increased from 27% up to 58% until a chloramphenicole concentration of 130 mg/L. 95,13% COD removal efficiency was obtained at a HRT of 19,2 days in ABR reactor at a chloramphenicole concentration of 130 mg/L. The VFA concentrations were zero as the HRTs was decreased from 38.4 days from 7.68 days throughout continuous operation of ABR reactor. The Maximum methane gas production rate (489,6L/day) was obtained at 19,2 days of HRT The maximum methane percentage varied between 60 and 68% at a HRT of 19.2 days. For maximum COD removal efficiency the optimum HRT was found to be 19,2 days. For maximum COD removal efficiency (E=98,12%) the optimum HRT was found as 19,2 days in aerobic reactor. The maximum total chloramphenicol removal efficiency was 100% in the sequential reactor system at an influent chloramphenicol concentration of 128.60 mg/L and a HRT of 38.4 days. In this study it was found that the ?chloramphenicole? antibiotic was mainly degraded (126.49 mg/L) in anaerobic ABR reactor while the remaining small part of this antibiotic (1.93 mg/L) was removed in the aerobic CSTR reactor.The kinetic constants found in the Monod and Grau kinetic models were found to be meaningfull for anaerobic degradation of streptomycin and chloramphenicol antibiotics.