An effective way to select slow-growing nitrifying bacteria by providing a dynamic environment.
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.
Xia
Li-Ping
LP
School of Environmental and Biological Science and Technology, Dalian University of Technology, Dalian 116024, People's Republic of China.
Zhang
Han-Min
HM
Wang
Xin-Hua
XH
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
D000644:Quaternary Ammonium Compounds; D010100:Oxygen