LAUSR

Considering the two unique factors of the plateau environment (i.e. water temperature and oxygen partial pressure), this paper explores the nitrogen and phosphorous removal of pilot-scale anaerobic-anoxic-aerobic (A2O) process. The experimental results show that none of the total phosphorous (TP), total nitrogen (TN) or NH4-N of the outlet water satisfied the Chinese national standard GB18918-2002, while COD only fulfilled the standard requirements under a few working parameters. The optimal values of the four working parameters were determined as: the optimal HRT=26.25 h, the optimal DO=3.0 mg/L, the optimal temperature=15°C. All these optimal values deviated greatly from the existing studies. The microbial densities corresponded poorly to the three working parameters, and were smaller than those under non-plateau environment; the number of indicator microorganisms had good correspondence with the optimal values of our experimental parameters.