Biological nitrogen and phosphorus removal using anoxic-anaerobic oxidation ditch under low temperature condition

A pilot-scale anoxic-anaerobic oxidation ditch process was used to investigate the influence of varying temperature on organic substance, nitrogen and phosphorus removal, and the efficiency of these pollutions removal in about 15 ˚C.The results indicated that when the temperature was dropped from about 25 ˚C to about 20 ˚C and about 15 ˚C, the efficiency of TN and NH 4 + -N removal was obviouly affected, although the operational parameters was optimized immediately, while COD and TP was almost not affected.When the temperature was about 15 ˚C, in the steady phase, the DO, MLSS, SRT and RSR were 1.5~2 mg/L, 3722~4085 mg/L, 18 day and 76 %, respectively, the concentration of COD, NH 4 + -N, TN and TP in effluent was 26.2 mg/L, 12.1 mg/L, 3.9 mg/L and 0.34 mg/L, respectively, and the removal rate of these pollutions was 90.7 %, 90.4 %, 73.2 % and 93.2 %, respectively.