不同运行策略对反硝化颗粒污泥培养的影响

Effect of different operation strategies on denitrifying granular sludge cultivation

反应器运行环境对反硝化颗粒污泥培养具有重要影响,在上流厌氧污泥床反应器内研究了不同运行策略培养颗粒污泥的脱氮效率、污泥性能和菌群结构,同时对比分析了快速和慢速提升氮负荷策略培养反硝化颗粒污泥的性能。结果表明:耦合提升策略培养反硝化颗粒污泥的脱氮效率达到93.29%以上,悬浮挥发性固体质量浓度为46.29 g/L,粒径主要分布在2.36~3.35 mm,胞外聚合物为119.03 mg/g VSS,反硝化优势菌Proteobacteria在颗粒污泥菌群中所占比例为61.92%;相较于慢速提升氮负荷策略,快速提升氮负荷策略促使污泥脱氮效率增加了5.48%,挥发性悬浮固体质量浓度增加了20.11 g/L,粒径为2.36~3.35 mm的污泥占比增加了10%左右,胞外聚合物增加了7.27 mg/g VSS,Proteobacteria所占比例增加了5.11%。研究表明,耦合提升策略能够培养出脱氮效率高且性能良好的反硝化颗粒污泥,快速提升氮负荷能够促进颗粒污泥脱氮效率增加、性能更好。

To explore the effect of culturing denitrifying granular sludge by nitrogen load and up-flow velocity coupled lifting strategies, nitrogen removal rate, sludge performance, and microbial community structure were studied during culturing process. Besides, the effects of rapidly and slowly increasing nitrogen load on the performance of denitrifying granular sludge were compared and analyzed. The results show that the nitrogen removal efficiency of denitrifying granular sludge cultured by coupled lifting strategies was more than 93.29%. Mixed liquid suspended solid, mixed liquid volatile suspended solid and their ratio was 78.25 g/L, 46.29 g/L and 0.59. Particle size was mainly in the range of 2.36 to 3.35 mm, and the ratio of those to all granular sludge was about 40%. Extracellular polymer substance was 119.03 mg/g VSS, the contents of protein and polysaccharide in the extracellular polymer were respectively 33.50 mg/g VSSand 26.00 mg/g VSS, and the ratio of them was 1.29. It should be noted that extracellular polymer substance was mainly tryptophan-like substances. The dominant denitrifying phyla Proteobacteria accounted for 61.92%, and the dominant denitrifying genera Hyphomicrobium, Bosea, Phreatobacter and Acetoanaerobium accounted for 28.00%, 0.92%, 3.66%, and 2.09%, respectively. Compared with the nitrogen slowly lifting strategy, the nitrogen removal efficiency increased by 5.48% by the nitrogen load rapidly lifting strategy. Mixed liquid suspended solid, mixed liquid volatile suspended solid and their ratio respectively increased by 20.97 g/L, 20.11 g/L, and 0.08. The proportion of sludge with a particle size of 2.36-3.35 mm increased by about 10%. Extracellular polymer substance increased by 7.27 mg/g VSS, the contents protein and polysaccharide in extracellular polymer respectively increased by 9.36 mg/g VSS and 7.35 mg/g VSS, and the ratio of them increased by 0.01. The proportion of Phreatobacter increased by 5.11%, Hyphomicrobium, Bosea, Phreatobacter and Acetoanaerobium respectively increased by 2.08%, 1.77%, 2.38%, and 4.13%. The results indicated that the coupled lifting strategies could culture the denitrifying granular sludge with high nitrogen removal efficiency and good performance. In the microbial community, the dominant denitrifying bacteria promoted sludge granulation and rapid and efficient denitrification by the excessive secretion of extracellular polymer substances, the metabolism of methanol and the neutralization with alkali substances produced by denitrification. In the microbial community cultured by the nitrogen load rapidly lifting strategy, the dominant denitrifying bacteria increase, which improves the denitrification efficiency and performance of granular sludge. In the microbial community cultured by the nitrogen load rapidly lifting strategy, the proportion of all dominant bacteria increased, so the nitrogen removal efficiency of granular sludge increased and the performance was better than that of the nitrogen load slowly lifting strategy.