Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha 410082, China.
Hubei Key Laboratory of Water System Science for Sponge City Construction, Wuhan University, Wuhan, 430072, China.
Sci Total Environ. 2022 Aug 15;834:155369. doi: 10.1016/j.scitotenv.2022.155369. Epub 2022 Apr 21.
The nutrients availability determines efficiency of biological treatment systems, along with the structure and metabolism of microbiota. Herein nutrients deficiencies on aerobic granular sludge were comparatively evaluated, treating wastewater with mass ratios of chemical oxygen demand : nitrogen : phosphorus being 200:20:4, 200:2:4, and 200:20:0.4 (deemed as nutrient-balanced, nitrogen-deficient, and phosphorus-deficient), respectively. Results revealed that both nitrogen and phosphorus deficiencies significantly raised the effluent qualities especially nitrogen removal. However, nitrogen deficiency aroused considerable growth of filamentous bacteria, while granules kept compact structure under phosphorus deficient condition. Extracellular polymeric substances (EPS) also varied in contents and structures in response to different wastewaters. Microbial community structure analysis demonstrated that nitrogen deficiency led to lower richness and higher diversity, while the reverse was observed under phosphorus deficient condition. Nitrogen deficiency mainly induced decrease of nitrifying bacteria, while similarly phosphorus deficiency led to loss of phosphorus accumulating organisms. Dramatic enrichment Candidatus_Competibacter and filamentous Thiothrix were found under nutrients deficiencies, in which the latter explained and indicated filamentous bulking potential especially under nitrogen limited condition. Bacterial metabolism patterns verified the functions of microbial community responding to nutrients via PICRUSt2 prediction mainly by up-regulating cell motility, and cellular processes and signaling. This study could aid understanding of long-term stability of aerobic granular sludge for low-strength wastewater treatment.
营养物质的可利用性决定了生物处理系统的效率，以及微生物群落的结构和代谢。在此，比较评估了好氧颗粒污泥中的营养物质缺乏情况，分别以化学需氧量：氮：磷的质量比为 200:20:4、200:2:4 和 200:20:0.4（分别为营养平衡、氮缺乏和磷缺乏）来处理废水。结果表明，氮和磷的缺乏都会显著提高出水质量，尤其是脱氮效果。然而，氮缺乏会引起丝状菌的大量生长，而在磷缺乏的条件下，颗粒保持紧凑的结构。胞外聚合物物质（EPS）的含量和结构也会因不同的废水而变化。微生物群落结构分析表明，氮缺乏会降低丰富度和增加多样性，而磷缺乏则相反。氮缺乏主要导致硝化细菌减少，而类似地，磷缺乏会导致聚磷菌的丧失。在营养物质缺乏的情况下，发现了 Candidatus_Competibacter 和丝状的硫丝菌的显著富集，其中后者解释并表明了丝状膨胀的潜力，特别是在氮限制条件下。细菌代谢模式通过 PICRUSt2 预测验证了微生物群落通过上调细胞运动、细胞过程和信号转导来响应营养物质的功能。本研究有助于理解好氧颗粒污泥在低强度废水处理中的长期稳定性。
