Study On Technology Of Removing Nitrogen From Wastewater Using Immobilized Microorganisms By Circulatory Freezing And Thawing Method

The nitrifying activated sludge nitrifying and denitrifying activated sludge and traditional activated sludge were immobilized with polyvinyl alcohol(PVA) and the immobilized pellets were prepared by circulatory freezing and thawing method. After cultivated the pellets were used to treat Composed NH4+-N Wastewater in fluidized bed reactor. The experiment results were as follows: The nitrifying activated sludge pellets have good capability of nitrification and NO2--N taked up more percentage in ammonium-N transfer reactant. Co-immobilized pellets can realize simultaneous nitrification and denitrification(SND). The best technical parameters were established through experiments. The traditional activated sludge pellets had nitrification to some extent. When used to treat wastewater composed NH4+-N and organic carbon source, the nitrifying activated sludge pellets and the activated sludge pellets can also produce SND phenomenon in a certain extent. The experiment results also indicated that the immobilized pellet' s life was more than 3 months.