title: [Monitoring the stoichiometric relation of ammonium oxidation with the titrimetry of hydrogen ion variation].
abstract: A set of automatically titrimetric system to monitor the hydrogen ion variation during biological wastewater treatment process in a batch bioreactor was developed, which consists of a batch bioreactor, data auto-acquisition and preservation unit, and titrant autodosing unit. The accuracy of measurement for the system was evaluated by measuring the stoichiometric ratio of hydrogen ion production amount to ammonium consumption amount of ammonium oxidation in an activated sludge system. The ratios measured in a 1L bioreactor with NH4+ -N concentrations of 1.67, 3.33, 8.33, 16. 66 and 30.00 mg/L as N respectively were very close to the theoretical value, and the relative errors were among 2.09%-6.34%. However, the relative errors in bioreactors of 1, 2, 3 and 4 L with NH4+ -N concentration of 16.66 mg/L as N were among 2.09%- -18.57%, and increased significantly with accretion of the volume of bioreactor. The buffers of bicarbonate and the ammonium, especially the titrimetric dynamic effects in a larger bioreactor are the primarily factors resulting in errors. This study provides an important approach for monitoring hydrogen ion variation in the process of biological wastewater treatment by titrimetry.
authors.affiliation: Department of Environmental Science, Chongqing University, Chongqing 400030, China. zhxin_512@163.com
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.forename: Dai-jun
authors.initials: DJ
authors.lastname: Zhang
authors.forename: Wen-ge
authors.initials: WG
authors.lastname: Zhang
authors.forename: Pei-li
authors.initials: PL
authors.lastname: Lu
mesh_terms: D057205:Automation, Laboratory; D019149:Bioreactors; D009576:Nitrobacter / Q000378:metabolism; D010084:Oxidation-Reduction; D011522:Protons; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012722:Sewage / Q000737:chemistry; D017186:Titrimetry / Q000379:methods; D014865:Waste Disposal, Fluid / Q000295:instrumentation* / Q000379:methods
chemical_list: D011522:Protons; D000644:Quaternary Ammonium Compounds; D012722:Sewage