Treatment Of High Salinity Wastewater By Using Ozone Catalytic Oxidation And Microbial Technology

The processing process of the high salinity organic wastewater is difficult, because of the salinity will corrosion the pipeline in the ordinary technology. And the high salinity will inhibit the growth of microbes. Ozone catalytic oxidation technologies can oxidize organics effectively. And other ingredients in the water could not influence the result of the treatment, so this technology has been used widely. In recent years, the study of halophilic bacteria technology becomes more and more. Experiments show that, halophilic bacteria in the activated sludge system can survive well under salinity surroundings through the domestication, and the COD has been removed efficiently.In this study, the high salinity wastewater was treated by using catalytic ozonation and microbial technology. Through optimizing the catalyst preparation conditions and operating conditions of process to achieve better result. The Fe, Mn and Cu were selected as the active component, and the activated carbon as the carrier, then the catalyst was made in the conditions that the impregnation time was 8h, the maturing temperature was 600℃, and the maturing time was 4h. The catalyst was used to catalytic ozonation on high salinity wastewater treatment. The COD removal efficiency of the Fe-carbon-O3 system, Mn-activated carbon -O3 system and Cu-activated carbon -O3 system was 53.5%, 42.4%and39.9%. The catalytic oxidation effect of the catalyst made of iron as the active component was significantly higher than the catalyst made of manganese and copper. Therefore, iron was identified as the best active component. Selected iron as the active component, then made catalyst at the condition that the maturing temperature was 600℃,the maturing time was 4h,and the impregnation time was different. The catalyst was used to catalytic ozonation on high salinity wastewater treatment. The COD removal efficiency of the Fe-carbon-O3 system was 49.6% when the soaking time was 6h. It was 15.5% higher than 4h. So the best impregnation time was 6h. Made catalyst at the condition that impregnation time was 6h, the maturing time was 4h and the maturing temperature was different. The COD removal efficiency of the catalytic ozonation was 71.6% when the maturing temperature was 700℃. The COD removal efficiency was 46.5% when the maturing temperature was 900℃. So the best maturing temperature was 700℃. Made catalyst at the condition that impregnation time was 6h, the maturing temperature was 700℃and the maturing time was different. The result of catalytic ozonation was that, the COD removal efficiency was 71.7% when the maturing time was 4h. And the COD removal efficiency reduced when the maturing time added. So the best maturing time was 4h.Under the different ozone flow conditions, 40g/L of the previous prepared catalysts were filled to the reactor, and oxidatated the high salinity organic wastewater. When the ozone into the air was 90mg/h, the reaction time was 50min, the COD removal efficiency was 52.7%. When the ozone into the air was 180mg/h, the COD removal efficiency increased to 75.9%, but into the air was continued to increase, the COD removal efficiency did not change significantly. So the best ozone into the air was 180mg/L. In the best ozone flow conditions, changing the amount of catalyst, the high salinity organic wastewater was oxidatated by ozone. When the amount of catalyst was 40g/L, the effect of the COD removal efficiency was best. Under the optimum conditions, compared the effect of ozone oxidation and catalytic oxidation, when the reaction time was 50 min, the COD removal efficiency of the ozone catalytic oxidation was 40.1%, more than ozone oxidation alone, and achieved a good treatment effect. After consecutive experiments 58h, the catalyst had remained a good catalytic effect, the COD removal efficiency was more than 70%, so the catalyst could be prolonged used.The activated sludge was inoculated in the SBR reactor, intermittent aeration, the concentration of NaCl was gradually increasing from 1000mg/L,2000g/L to 3000mg/L. And the activated sludge was domesticated, the COD removal efficiency were 84.7%, 78.4%, 72.0%. So the degradation of the activated sludge could be recovered by domestication, and the final COD removal efficiency could be maintained above 70%. When the concentration of NaCl increased from 4000mg/L to 5000mg/L, the COD removal efficiency could be restored to more than 70% after domesticated 10d. But when the NaCl concentration was 6000mg/L, the COD removal efficiency was only 65%. So under the experimental conditions, influent NaCl concentration could not too large. Finally, the ozone oxidation runned in series with the SBR, after a period of time, the system stability was better, and had a good treatment effect for the high salinity organic wastewater.