The COMPARISON OF MICROBIAL COMMUNITIES BETWEEN A/A/O AND A/O PROCESS IN THE SAME WASTEWATER TREATMENT PLANT BY NESTED PCR-DGGE METHOD

摘要

The differences of microbial communities in two different systems were investigated by denaturing gradient gel electrophoresis (DGGE) of nested polymcrase chain reaction (nested PCR) amplified 16S rRNA gene fragments of bacteria and 26S rRNA gene fragments of yeast in the same wastewater treatment plant of Beijing. The two different systems adopt anoxic-anaerobic-aerobic process (A2O) and anoxic-aerobic process (AO) respectively. The bacterial, actinomycetic, ammonia-oxidizing bacterial (AOB) and yeast communities of the two different processes were compared separately. The results showed that AOB communities were of higher similarity (77.5%) corresponding to similar ammonium removal, while bacterial, actinomycetic and yeast communities presented obvious differences (similarity 55.1%, 53%, 52.8% respectively). FISH results showed that the total AOB cell numbers of the A/A/O system can be accounted for 3.6±0.2%, while in the A/O system it is only 1.9±0.2%. The amount of bacterial, actinomycetic and yeast populations in the A/A/O system was higher than that of the A/O system. The existence of an anaerobic environment in the A/A/O system did seem to affect the microbial community structures significantly. Meanwhile, the redistribute of the raw sewage in the A/A/O system may also affect the microbial community structures to some extent. The higher species richness in A/A/O system may be related to the shorter HRT in aerobic compartment.