Microbial Diversity And Their Main Function In Gravel Contact Oxidation Reactor

The disposal of excess sludge is a difficult problem in biological treatment for sewage and industry wastewater. Gravel contact oxidation reactor (GCOR) is one of excess sludge reduction techniques. This article researched the mechanism of excess sludge reduction by analyzing the community structure of the microbes in the reactor, and the function of the dominant microbes.After biomass cultivating and treatment running in GCOR for 5 months, the qualities of treated water were better than sewage discharge standards (Integrated wastewater discharge standard level I, GB 8978-1996) and without excess sludge disposal.In the reactor s running period, we observed the biomass extracted from biofilm and sediment sludge with microscope. We found that there were abundant kinds of protozoa and metazoa. These mini animals made the food chains longer and more complex, which increased the energy losing and reduced the energy used to synthesize new organism. Moreover, these mini animals preyed a great deal of bacterium and solid organism, and contributed to the reducing of excess sludge.Phylogenetic diversity of procaryotae and their function to excess sludge demineralization in gravel contact oxidation reactor (GCOR) were studied by constructed 16SrRNA library, PCR-based molecular surveys of environmental 16SrRNA genes. The sequence analysis of 16SrRNA genes indicated that reactor bacterial communities were composed of aerobic bacteria group and anaerobic bacteria group. The dominant members were respiratory metabolize microbe Pseudomonas and fermentative metabolize microbe Bacteroidetes bacterium/Cytophaga, and their 16SrRNA sequences accounted for 17%, respectively. Non-dominant members in aerobic group included α-, β -, and Y Proteobacterium, Nitrosospira, Chlamydia, Gluconoba cter and Agrobacterium. Anaerobic members are Spirochaeta sp., delta preobacterium, Denitrifying bacterium, Geothrix and Eubacterium. Such a diversity of microbes contributed to both organic wastewater degraded and least emission of excess sludge mainly.