title: Nitrogen removal via nitrite at normal temperature in A/O process.
abstract: In order to study the nitrogen removal via nitrite at normal temperature in anoxic/oxic (A/O) process for treating domestic wastewater, the influence of pH, free ammonia (FA), dissolved oxygen (DO), and hydraulic retention time (HRT) were studied. Results indicated that it was possible to remove nitrogen via nitrite in A/O process, if the temperature was between 18 and 25 degrees C and pH was below 7.5. Even if FA was as low as 0.06 mg NH3-N/L, it would inhibit the nitrobacteria. However, FA could not be the sole factor. Whether denitrification went thoroughly or not could affect the nitrification pathway. If denitrification went well, nitrite accumulation could recover in a short while. Nitritification lagged nitratification, so that short HRT would help nitrite accumulation. On the other hand, extended aeration would reduce nitrite accumulation.
authors.affiliation: College of Municipal and Environmental Engineering, Harbin Institute of Technology, P.R. China.
authors.forename: Yong-Zhen
authors.initials: YZ
authors.lastname: Peng
authors.forename: Tao
authors.initials: T
authors.lastname: Chen
authors.forename: Wen-Jun
authors.initials: WJ
authors.lastname: Tian
mesh_terms: D009573:Nitrites / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry / Q000302:isolation & purification*; D010100:Oxygen / Q000737:chemistry*; D013696:Temperature; D014865:Waste Disposal, Fluid; D018508:Water Purification / Q000379:methods*
chemical_list: D009573:Nitrites; D009584:Nitrogen; D010100:Oxygen