城市污水培养好氧颗粒污泥的中试研究

Cultivation of Aerobic Granules in a Large Pilot SBR with Domestic Sewage

以城市污水为处理对象,在中试SBR反应器中接种厌氧消化污泥,经过210 d运行,培养出了平均粒径在330μm的好氧颗粒污泥.实验表明,经过前3个月较低的进水有机负荷,反应器对污染物的去除效果逐步提高并达到稳定,活性污泥中与脱氮除磷相关的微生物大量富集.运行周期缩短为6 h,污泥的沉降性能和污染物去除特性保持良好,同时污泥平均粒径开始增大.好氧颗粒污泥完全形成以后,SVI值为30 mL.g-1,污泥浓度MLSS达到8.8 g.L-1,MLVSS/MLSS增至82%,氧利用速率OUR达到5.32 mg.(min.L)-1.颗粒外层以杆状菌为主,内层主要是球菌.单个周期内颗粒污泥对COD和总磷的去除率保持在90%,氨氮几乎完全去除,出水中无硝氮和亚硝氮累积,总氮的去除率达到80%,实现了良好的同步硝化反硝化和同步脱氮除磷效果.

The cultivation of aerobic granules in a large pilot-scale SBR was investigated using domestic wastewater.After operation of 210 days,the granules with a diameter of 330 μm were successfully formed by seeding anaerobic digested sludge.Results showed that,during the first three months of operation under low organic load of influent,removal efficiencies of pollutants increased steadily including COD,NH 4＋-N,total nitrogen（TN） and total phosphorous（TP）.Meanwhile,microorganisms related to nitrogen and phosphorous were enriched.The organic load was enhanced since cycle time was shortened to 6 h,and the operational performance of the reactor still remained stable.Moreover,the average particle size of the sludge started to increase,along with excellent settling ability and high bioactivity.After the formation of aerobic granules,Sludge volume index（SVI） was maintained at 30 mL.g-1 and the mixed liquor suspended solid（MLSS） concentration in the SBR reached 8.8 g.L-1.MLVSS /MLSS ratio of the sludge increased to 82% with a high oxygen uptake rate（OUR） of 5.32 mg.（min.L）-1.Bacillus was dominant on the outer layer of granules,while cocci were mainly located inside.The average COD and TP removal efficiencies kept at 90% and NH 4＋-N was almost completely depleted,NO 3--N and NO 2--N were not accumulated in the effluent.The aerobic granules were also capable of achieving simultaneous nitrification and denitrification（SND） in a single SBR cycle,which resulted in a high TN removal efficiency of 80%.