[Microecology of the anaerobic ammonium oxidation reactor]

The microbial community structure and biodiversity in the ANAMMOX system were studied by applying the methods of microtechnic, separation and purification technology of microorganisms, and molecular biotechnology. The ANAMMOX microbial population in an upflow anaerobic sludge blanket (UASB) bioreactor and a UASB-biofilm bioreactor was successfully enriched in the laboratory with inorganic and dark condition. The removal efficiencies of NH4+-N and NO2(-)-N in UASB reactor were 99.99% and 99.9% respectively. For the UASB- biofilm, they were 99.3% and 97.4% respectively in an optimal condition in which the temperature was 30-34 degrees C and the pH was 7-8. In traditional methods of identifying microorganism, the population of bacteria, actinomycete and fungi were researched and the species in the two reactors were basically identical. Most of the microorganisms were anaerobic and anoxic bacteria. The size of the preponderant bacteria was (0.6-0.8) microm x (0.9-1.2) microm from the scanning electron micrographs of sludge cultivated in the two reactors, and the shape was oval. The rate of this preponderant bacteria was above 90%. The result of the denaturing gradient gel electrophoresis(DGGE) and 16S rDNA digested reveals that there was one predominant species and the biodiversity was not high.