| The physical properties and microbiological characteristics of aerobic short-cut granular sludge, which was cultivated in a lab-scale aerated upflow sludge bed (AUSB) reactor, were investigated. When the short-cut nitrification process was performed stably, the ratios of VSS/SS of short-cut granules were kept at about 80%, the amount of granules with diameter larger than 1.0 mm was about 70% of the total, and the wet density of granules with diameter larger than 0.8mm was about 1?022 kg/m3.The fluorescence in situ hybridization (FISH) results indicated the ammonia oxidation bacteria (AOB) were mainly located in the surface layer of the granules, and the nitrite oxidation bacteria (NOB) were in the inner layer. The results of most probable number (MPN) showed that, as the short-cut process was operated stably, the amount of AOB was much more than that of NOB, and sometimes the AOB amount was even 10 thousands times more than that of NOB. All these results indicated that, using the seed granules or their debris as the support media, AOB and NOB were attached and grown on the surface of the media, and finally the aerobic short-cut nitrification granules were formed. |
