低碳氮比废水好氧颗粒污泥系统稳定性及微生物种群多样性研究

低碳氮比(C/N)废水处理是含氮废水处理中的难题之一.本实验在C/N为4:1和2:1(COD和NH₄⁺-N浓度分别为400 mg·L^-1和100 mg·L^-1,400 mg·L^-1和200 mg·L^-1)条件下,考察好氧颗粒污泥系统对低碳氮比废水的处理效果、长期运行稳定性,研究C/N对好氧颗粒微生物结构变化的影响.研究结果表明,在C/N为4:1的废水中接种活性污泥培养好氧颗粒污泥,形成的颗粒沉降性能良好,MLSS为4.94 g·L^-1,SVI30为40 mL·g^-1,COD去除率90%以上,氨氮去除率接近100%.降低碳氮比,即C/N为2:1后,好氧颗粒的物理及硝化性能无明显变化,MLSS为11.38 g·L^-1,SVI₃₀/SVI₅维持在1左右,COD去除率大于85%,氨氮去除率98%.碳氮比降低使颗粒微生物多样性减少,其中陶厄氏菌受影响较小,而硝化功能菌出现更替:噬氢菌、食酸菌、里德拜特氏菌消失,鞘氨醇单胞菌、束缚杆菌等成为优势菌种.实验表明,该低碳氮比条件下好氧颗粒污泥系统能够稳定运行,且具有优良的处理性能.

Stability and microbial diversity of the aerobic granular sludge under low carbon to nitrogen ratio

Wastewater with low carbon to nitrogen ratio(C/N)is one of the difficulties in the treatment of nitrogen containing wastewaters at present.This study investigated the system performance,long-term stability and microbial structure of the aerobic granular sludge system,of which the aerobic granules were cultivated with C/N of 4:1 and 2:1(COD and ammonia nitrogen concentrations of 400 mg·L^-1and 100 mg·L^-1,and 400 mg·L^-1and 200 mg·L^-1),respectively.Results showed that the formed aerobic granules have good settling performance when the aerobic granules was cultured by inoculating activated sludge in the wastewater with C/N of 4:1.The mixed liquid suspended solids(MLSS)was found to be 4.94 g·L^-1,the sludge volume index(SVI₃₀)was 40 mL·g^-1,and the removal efficiency for COD was over 90%,for ammonia was close to 100%.Reducing C/N to 2:1,physical properties and nitrifying ability of the aerobic granules were barely affected.MLSS increased to 11.38 g·L^-1while the ratio of SVI30 to SVI5(SVI₃₀/SVI₅)maintained at around 1.Removal efficiency of COD and ammonia are above 85%and 98%,respectively.The reduction of C/N from 4:1 to 2:1 decreased the diversity of microbials in the aerobic granules.Thauera was slightly affected,while functional nitrifying species showed alternations.Sphingomonas,Haliscomenobacter and Ohtaekwangia became dominant species,whereas Hydrogenophaga,Acidovorax and Leadbetterella disappeared.These findings suggested that the aerobic granular sludge has good performance and long-term stability under the low C/N of 4:1 and 2:1.