A Study On The Microbial Characteristics And Mechanism Of Pollutants Degradation In Biological Activated Carbon Bed

With the help of financial assistance of the national science fund, this research used the techniques of ozone-biological activated carbon to carry out the experiment of depth treatment of sewage in Beishi Qiao sewage purification center, Xi'an, which aimed at the recycling of sewage in the city. Simultaneously, the characteristics of microorganism and mechanism of pollutants degradation in biological activated carbon bed were systematically studied, and a preliminary kinetic model of biodegradation was established.Using the microbial method of PCR-DGGE, Lipid-P, bacterial cultivation and et al, we studied the changing tendency and influencing factors of the biomass and biology community in the carbon layers of different heights within the biological activated carbon bed. The results show that there are 16 kinds of primary microorganisms in the biological activated carbon bed, within them, the aerobic bacteria is in the ascendant. In the steady ecosystem, there are also protozoa and metazoa existing. All of the above results suggest that the microorganisms in the biological activated carbon bed are very abundant, and the ecosystem of it is very steady. Meanwhile it can also be found that the biomass is decreasing along the biological activated carbon bed from the top to the bottom, and the primary influencing factors are temperature and dissolved oxygen.In the long term experiment, we analyzed and calculated the changing characteristic of NH₃-N, NO₃-N and NO₂-N in the biological activated carbon bed. A regularity how the index of "NH₃-N, NO₃-N, NO₂-N" change in the biological activated carbon bed is educed. Through both the adsorption of activated carbon and degradation of microbes, the index of NH₃-N is reducing, NO₃-N is rising, and NO₂-N maintained at a rather low level. Within the value of the variations, the part which is consumed by microbial metabolism is less and less as the depth of bed increasing. Meanwhile, the DO consumed by microbial respiration is less and less. As a result, when the depth of activated carbon bed increases, the rate of microbial metabolism is decreasing, and microbes are reducing.Used for comparison with the biological activated carbon, we tested a biological ceramic filter bed, and got its organism biodegradation rule. Then based on the basic equations of microbial growth dynamics—the Monod equation, we deduce the biodegradation dynamic equation of biological activated carbon bed. To sum up the above arguments, we draw the conclusion that the biodegradation kinetic model of the zone-biological activated carbon bed coincides with high matrix density organic matter degeneration model, which is a first order reaction. According to this equation, we have studied the adsorption performance of biological activated carbon bed, and found that as the microbe deducing in the bed, its adsorption is advanced.