Research on removal of nitrite by the immobilized denitrifying bacteria

The effects of three kinds of immobilization methods on the removal of nitrite by denitrifying bacteria were studied including using the sodium alginate( SA),polyvinyl alcohol( PVA),polyvinyl alcohol and sodium alginate mixture( PVA + SA) for pack material respectively. At the same time,influence factors of removal of nitrite were investigated in detail for the immobilized denitrifying bacteria balls made by polyvinyl alcohol and sodium alginate mixture. The results showed that the balls of immobilized denitrifying bacteria made by polyvinyl alcohol and sodium alginate mixture had obvious advantages compared with balls made by polyvinyl alcohol and sodium alginate single. The optimal conditions were ratio of polyvinyl alcohol to sodium alginate 10∶ 1,28 ℃,with the glucose as carbon source and ratio of carbon to nitrogen 2. 5∶ 1. Under the optimal conditions,maximum removal rate of nitrite nitrogen could reach 92% in72 h.