The microbial diversity and performance in an anoxic aerobic membrane bioreactor

摘要

A submerged membrane bioreactor (single stage MBR) is usually used as a substitute for sedimentation tank in the traditional activated sludge process. An additional anoxic tank (2 stage MBR) was added to enhance the total nitrogen (TN) and total phosphate (TP) removal rates with the recycling ratio (r) controlled at 0.5,1.5 and 2.5 for testing the optimal substrate removal rates in this study. While r from the aeration tank to the anoxic tank was controlled at 1.5 with the sludge and hydraulic retention time (SRT and HRT) were kept at 10 days and 15 hours respectively in the treatment of domestic wastewater, the TN and TP removal rates went as high as 76.3% and 28.3%. In the 2 stage MBR, using the clone-DGGE (denaturing gradient gel electrophoresis) method, it was found Acidovorax temperans functioned as the denitrifier, Propionibacter pelophilus like the polyphosphate-accumulating organisms (PAO), enhanced the phosphate removal, and Haliscomenobacter hydrossis as a filamentous bacterium without interfering with subsequent low suspended solids concentration.