| With the features of high COD, high ammonia concentration, poor wastewater biodegradability and bio-toxicants, the biological treatment of tetracycline antibiotics wastewater is difficult. It was necessary to study on the enhanced treatment process in the tetracycline antibiotics wastewater after biological treatment in order to meet the new discharge limits.This paper, basised on the characteristics of tetracycline antibiotics wastewater, research the effects of anaerobic biological toxicity under the pure tetracycline-HC l and oxytetracycline surroundings. UASB-A/O-Fenton combined process was used to treat tetracycline antibiotics wastewater. This paper study the feasibility and quick start method for using aerobic sludge as seed sludge to start UASB reactor, optimize running parameters of the combined process,and come up with discharge standards of tetracycline antibiotics wastewater. The main results were shown as following:(1)Pure materials as tetracycline-HCl and oxytetracycline effect anaerobic biological activity. They all have inhibition to methane bacteria. Slight inhibition was caused when tetracycline-HC l and oxytetracycline in concentration of 50 mg/L. It will produce metabolic toxicity for anaerobic microorganism when tetracycline-HC l and oxytetracycline at low concentrations, and they show bactericidal effect under the high concentrations. Furthermore, two antibiotics affect the anaerobic biological activity by inhibiting the activity of propionate-degrading bacteria and butyrate-degrading bacteria.(2)The test investigates the feasibility of aerobic sludge inoculation starting UASB reactor. Finally, inoculated with aerobic sludge of UASB reactor was started up successfully by using glucose substrate under low load, multiple stages to improve concentration of tetracyclines wastewater and influent load, the volume loading reached 3.60 kg COD/(m3·d) and the removal rate of COD was 60%. By compared anaerobic sludge inoculated to aerobic sludge inoculated, the control conditions with aerobic sludge inoculated is maintaining the alkalinity at above 1500mg/L, p H keeping 6.50~7.50, ALK/VFA being greater than 4 and MLSS holding 30g/L.(3)UASB-A/O biological combined processes were used to treat tetracycline antibiotics wastewater. After start- up and load enhance stage, tetracycline wastewater enhancement stage and stabilization stage, the biological combined process treated tetracycline wastewater successfully by gradually increase the tetracycline antibiotics wastewater methods. The removal rate of COD was higher than 90%, the removal rate of ammonia nitrogen and TN was also above 60%. The HRT was 24 h in UASB, the volume loading reached 6.90 kg COD/(m3·d), the removal rate of COD was 75% and gas production rate reached 0.32L/g COD. A/O reactor was ran under the HRT for 32 h, the reflux ratio of 300%, maintaining the sludge concentration in 3500~4000 mg/L, the removal rate of COD, ammonia nitrogen and total nitrogen were 70%, 60% and 60%, respectively.(4)Fenton process was used to decolorize the secondary effluent. The optimal conditions were molar ratio of Fe2+/H2O2 of 1:20, H2O2 of 0.05mol·L-1, reaction time of 120 min and initial p H of 4. Under the optimal conditions, the chroma and COD removal rates were above 90% and 65%.By comparing the organic substances of raw water and treated water using LC-MS,it is speculated that the carboxyl and hydroxyl group substances such as pyridine, aniline, amides and ketones resulted in chroma of secondary biochemical effluent.(5)UASB-A/O-Fenton combined process were used to treat the tetracycline antibiotics wastewater, The result of the operation indicates that the monitoring system works well and removal efficiency of the COD, ammonia nitrogen, TN and chrominance were 97%, 80%, 77% and 90%. Effluent quality can meet the “Discharge Standards of Water Pollutants for Pharmaceutical Industry Fermentation Products Category”(GB21903-2008). By combined process, tetracycline antibiotics wastewater is processed in keeping with the standards. |
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