处理实际生活污水短程硝化好氧颗粒污泥的快速培养

以普通序批反应器(Sequencing Batch Reactor,SBR)和气提式序批反应器(Sequencing Batch Airlift Reactor,SBAR)处理低COD/TN的实际生活污水,考察了不同沉淀时间以及反应器类型对快速培养短程硝化好氧颗粒污泥(Aerobic Granular Sludge,AGS)的影响.试验结果表明,沉淀时间为15min时,SBR和SBAR系统中均为全程硝化,当将沉淀时间分别改为5min、8min后的第17d和第16d时,两个反应器中均形成AGS,并且AGS与絮状污泥共存;此时两系统均由全程硝化转化为短程硝化,出水NO2-/(NO2- NO3-)平均值分别长期维持在98.7%和85.6%左右.本试验中以沉淀时间作为选择压,快速启动了具有短程硝化功能的序批式AGS反应器.由于AGS固有结构对氧传质的限制,使亚硝酸氮氧化受阻即抑制了亚硝酸氮氧化细菌的活性,从而产生了亚硝酸氮积累现象.DO是造成本研究中出现短程硝化的主要原因,而pH值、游离氨、温度、污泥龄等因素都不是导致短程硝化的关键因素.污泥颗粒化后,两个系统中NH4 -N降解速率分别提高了2.6倍和2.4倍.

Rapid cultivation of aerobic granular sludge for shortcut nitrification of domestic wastewater

In order to investigate the effects of settling time and reactor type on aerobic granulation of nitrifying bacteria,low COD/TN ratio domestic wastewater was treated in a sequencing batch reactor(SBR) and a sequencing batch airlift reactor(SBAR).When the settling time was 15 min in both the SBR and SBAR,the type of nitrification was complete nitrification.When the settling time was decreased from 15 min to 5 min in the SBR,aerobic granular sludge appeared and coexisted with the floc-like sludge after 17 days.The same phenomena occurred after 16 days in the SBAR when the settling time was decreased to 8 min.At the same time,the complete nitrification changed to short-cut nitrification and the average effluent NO-2/(NO-2 NO-3) was 98.7% in the SBR and 85.6% in the SBAR.The short-cut nitrifying organisms were rapidly cultivated in both SBR and SBAR by using settling time as selection pressure.Due to the limitations of dissolved oxygen diffusion in the aerobic granular sludge and the different affinities for oxygen between nitrite oxidizing bacteria and ammonia oxidizing bacteria,nitrite accumulation occurred in both SBR and SBAR.Of the factors tested,(i.e.pH,free ammonia concentration,temperature and sludge retention time) dissolved oxygen was the main stress which promoted short-cut nitrification.The rate of ammonia oxidation by the aerobic granular sludge was 3.6 and 3.4 times as fast as that of the activated sludge in the SBR and SBAR,respectively.