title: An effective way to select slow-growing nitrifying bacteria by providing a dynamic environment.
abstract: In this study, two laboratory scale sequencing batch reactors (SBRs) were conducted to study the stability of aerobic granules. The strategy was involved in stepwise increase in ammonium (NH4+-N) concentration in the influent. Results showed that the activity of nitrifying bacteria and diameter of the aerobic granules significantly increased with gradually increasing NH4+-N, which reached persistently new balances by homeostasis. As a result, the stability of aerobic granules was remarkably enhanced. The value of sludge volume index (SVI) was below 25 ml/g, the mean settling velocity was excellent up to 107 m/h. The NH4+-N removal efficiency averaged above 99% and total nitrogen (TN) removal was greatly enhanced and could reach 68%. Besides dissolved oxygen, the granules size was also a dominant factor to influence denitrification, which could gradually increase in variable conditions through homeostasis. Stable, dense and well-settling nitrifying granules can be developed for simultaneous nitrification and denitrification removal.
authors: School of Environmental and Biological Science and Technology, Dalian University of Technology, Dalian 116024, People's Republic of China.
authors: Li-Ping
authors: LP
authors: Xia
authors: Han-Min
authors: HM
authors: Zhang
authors: Xin-Hua
authors: XH
authors: Wang
mesh_terms: D000332:Aerobiosis; D001419:Bacteria / Q000254:growth & development / Q000302:isolation & purification* / Q000378:metabolism*; D019149:Bioreactors; D006706:Homeostasis; D010100:Oxygen / Q000378:metabolism; D010316:Particle Size; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D049490:Systems Biology; D014865:Waste Disposal, Fluid
chemical_list: D000644:Quaternary Ammonium Compounds; D010100:Oxygen