Study On Degradation And Salt Tolerance Of Activated Sludge Organics Under Pure Oxygen Aeration

In recent years, the use of industrial wastewater treated by pure oxygen aeration has become one of research hotspots in the field of environment, and it is widely used to treat high concentration of refractory industrial wastewater. Pure oxygen aeration system has the characteristic of high oxygen transfer rate, good load to impact, less residual sludge, low energy consumption and the problem of sludge bulking and foam appeared less, the system can effectively remove pollutants in contaminated water,reduce the load of pollutants in water and has good ecological and environmental effects.At the same time, compared to ordinary air aeration, pure oxygen aeration can treat high concentrations of industrial wastewater efficiently, and can fully use oxygen to remove impurities in water. This subject, using activated sludge as the research object,investigates the characteristics and salt-resistant property of activated sludge with pure oxygen aeration. The conclusions of the article are summarized as follows:Studies about the characteristics of activated sludge with pure oxygen aeration show that: pure oxygen has high oxygen transfer rate, which allow more oxygen to participate in biodegradation in the same aeration quantity. Pure oxygen aeration system has a significant advantage in degrading organics rapidly, whose organic degradation rate is 1.7 times of air aeration when the initial TOC is about 100mg/L and the sludge concentration is 2000mg/L. When treats the ordinary wastewater, the contents of EPS and SMP in pure oxygen aeration was lower than that of air aeration, which have an important effect on the wastewater treatment up to standard. There is a significant positive correlation between the EPS and the SMP (r=0.947). When the high-concentration wastewater which initial TOC is 500mg/L, is treated by activated sludge with pure oxygen aeration, the sludge concentration of 8000 mg/L can obtain higher removal rate of organic substance at three typical sludge concentrations.Studies about using activated sludge process with pure oxygen aeration to treat the salty wastewater show that: In the range of 0-1.5% salinity, pure oxygen aeration can not only promote microorganism degradation of organics, but also make more EPS to be consumed. When treating the high salinity wastewater(2-5%), EPS in pure oxygen aeration is more than in air aeration in the end of reaction, because the response of cells against salinity is bigger in the pure oxygen aeration, and then secrete more EPS. Part of the microorganism will dead when facing the stress of the salinity environment, cells death will release SMP so that the SMP in the end of the reaction increase in air and pure oxygen aeration.When treating high salinity wastewater by sequencing batch reactor activated sludge with pure oxygen aeration, the content of extracellular protein is higher than the extracellular polysaccharide in activated sludge, which is the main component of EPS in activated sludge. Whether in high salinity or low salinity environments, SVI has a significant linear correlation with EPS,the extracellular protein and extracellular polysaccharide affect the sedimentation of activated sludge.