title: [Analysis of Precipitation Formation in Biofilm CANUN Reactor and its effect on Nitrogen Removal].
abstract: A CANON reactor with polymeric sponge as carrier was started by incubating sludge from another CANON reactor using synthetic inorganic ammonia-rich wastewater as raw water, and was operated at 30 degrees C +/- 1 degree C, pH 6.92-8.52. The precipitation on the surface of carriers was studied in this paper, including influence on nitrogen removal efficiency, causes for formation and composition. The results showed that: (1) the precipitation could influence the distribution of substrate to undermine the performance of CANON reactors; (2) the precipitation was calcium carbohydrate; (3) the production of precipitation may be a common result of four effects that were the regulatory effect of microorganisms on pH value, stripping effect, the role of extracellular polymers, adsorption of sponge and simultaneous chemical, biological reactions; (4) once the precipitation formed, it was difficult to recover to normal. Therefore, some measures are necessary to avoid precipitation, including: (1) raw water pretreatment to reduce the concentrations of Ca2 and Mg2. (2) ensuring short-cut nitrification stable, which could avoid increase of pH because of reduction of DO; (3) we can choose other carriers to reduce precipitation, which must ensure the optimal total nitrogen removal performance and stable short-cut nitrification.
authors.forename: Kun-ming
authors.initials: KM
authors.lastname: Fu
authors.forename: Hui-fang
authors.initials: HF
authors.lastname: Wang
authors.forename: Zao-rong
authors.initials: ZR
authors.lastname: Zuo
authors.forename: Fu-guo
authors.initials: FG
authors.lastname: Qiu
mesh_terms: D000641:Ammonia; D018441:Biofilms; D019149:Bioreactors; D011232:Chemical Precipitation; D058440:Denitrification; D058465:Nitrification; D009584:Nitrogen / Q000032:analysis*; D012722:Sewage; D062065:Wastewater / Q000737:chemistry*
chemical_list: D000641:Ammonia; D009584:Nitrogen; D012722:Sewage; D062065:Wastewater