TY - JOUR ID - TI - Nitrogen and phosphorus removal in pilot-scale anaerobic-anoxic oxidation ditch system AU - PENG Yongzhen AU - HOU Hongxun AU - WANG Shuying AU - CUI Youwei and Zhiguo Yuan VL - 20 IS - 4 PB - SP - 398 EP - 403 PY - JF - Journal of Environmental Sciences JA - J. Environ. Sci. UR - http://www.jesc.ac.cn/jesc_en/ch/reader/view_abstract.aspx?file_no=2008200403&flag=1 KW - oxidation ditch; biological nitrogen removal; biological phosphorus removal; simultaneous nitrification and denitrification (SND); pilot scale; municipal wastewater AB - To achieve high e ciency of nitrogen and phosphorus removal and to investigate the rule of simultaneous nitrification and denitrification phosphorus removal (SNDPR), a whole course of SNDPR damage and recovery was studied in a pilot-scale, anaerobicanoxic oxidation ditch (OD), where the volumes of anaerobic zone, anoxic zone, and ditches zone of the OD system were 7, 21, and 280 L, respectively. The reactor was fed with municipal wastewater with a flow rate of 336 L/d. The concept of simultaneous nitrification and denitrification (SND) rate (rSND) was put forward to quantify SND. The results indicate that: (1) high nitrogen and phosphorus removal e ciencies were achieved during the stable SND phase, total nitrogen (TN) and total phosphate (TP) removal rates were 80% and 85%, respectively; (2) when the system was aerated excessively, the stability of SND was damaged, and rSND dropped from 80% to 20% or less; (3) the natural logarithm of the ratio of NOx to NH4 + in the e uent had a linear correlation to oxidation-reduction potential (ORP); (4) when NO3?? was less than 6 mg/L, high phosphorus removal e ciency could be achieved; (5) denitrifying phosphorus removal (DNPR) could take place in the anaerobic-anoxic OD system. The major innovation was that the SND rate was devised and quantified. ER -