Experimental Study On Treatment Of Restaurant Wastewater With UV-Oxidation-SBR System

Restaurant wastewater has been a hot point of city environmental administration. In view of restaurant wastewater's speciality, only UV-Oxidation system ,only SBR system and UV-Oxidation- SBR system were used to treat restaurant wastewater, respectively.Investigations had been performed on UV-Oxidation system firstly, and emphases had been put on experimental analysis on UV radiation time and COD concentration. As the pretreatment of restaurant wastewater, during the process of UV-Oxidation, big molecules had been divided into small molecules, and unbiodegradable substances were also converted into biodegradable substances in the wastewater, so appropriate condition was provided for subsequent aerobic treatment.Experiment results showed that ,with initial COD 2100mg/L,10min of UV radiation time. The COD,BOD and grease removal efficiencies were 47.74%,33.62% and 77.92%,mostly unbiodegradable grease in the restaurant wastewater was removed,and the ratio of BOD/COD also increased in the process of UV-Oxidation. After that the removal efficiencies were unconspicuous.Secondly investigations had been performed on only SBR system. Experiment results showed that SBR system had good effect with the restaurant wastewater. With initial COD 2100mg/L, aerated 8 hours, 30L air/(L·h) of aeration capacity, MLSS 3000mg/L, the effluent COD was about 176.56 mg/L, the COD,BOD and grease removal efficiencies were 91.81%,93.43% and 93.65%.At last investigations had been performed on UV-Oxidation- SBR system, the UV-Oxidation with SBR system experiment results showed that, in the condition of approximate influent and experiment condition, after 10min of UV radiation and aerated 8 hours, the COD and grease removal efficiencies were 93.67%, and 95.60%. Comparing to only SBR system, the removal efficiency was much higher. Under optimal experimental conditions which were 10min of UV radiation time , 30L air/(L·h) of aeration capacity, MLSS 3500mg/L and pH 7, after aerating 8 hours, the COD,BOD and grease removal efficiencies were 97.52%,98.27% and 98.53%.According to the above research results, UV-Oxidation- SBR system is recommended in treating restaurant wastewater. This system had lots of advantages including high removal efficiency, short aerated time, strong ability against shock loading and less sludge bulking. What's more, UV-Oxidation could act as an emergency measure to the SBR system in very flexible way. Under optimal experimental conditions, the system ran 10 days and the removal efficiency was very stable. The effluent come up to theⅡlevel national wastewater comprehensive discharge standard(GB8978-1996).