College of Marine and Environmental Sciences, Tianjin University of Science & Technology, Tianjin, 300457, China.
College of Engineering and Technology, Tianjin Agricultural University, Tianjin, 300384, China.
Environ Sci Pollut Res Int. 2018 Mar;25(7):6240-6250. doi: 10.1007/s11356-017-0935-9. Epub 2017 Dec 14.
Purifying tank as a compact biofilm reactor has been widely used to remove organic matter in rural sewage, but its potential for nitrogen removal is rare to be discussed. This study developed a lab-scale compact biofilm reactor to realize an efficient nitrogen removal performance by step-feed, intermittent aeration, and immobilization technique. The results show that an efficient simultaneous nitrification and denitrification (SND) process took place by feeding with synthetic wastewater under high C/N ratio of 2 and with real sewage as well, mainly due to the step-feed. The average removal efficiency of total inorganic nitrogen arrived at 72.7 and 63.3% for synthetic wastewater and real sewage, respectively. Besides the step-feed operation, the intermittent aeration was adopted to enhance SND, which allowed hydraulic behavior of compact biofilm reactor following the model of completely stirred tank reactor. The high-throughput sequencing analysis indicates that Sphaerotilus became the dominant genera with relative abundance of 30.29% under high C/N ratio, and the nitrifiers were not greatly inhibited. Moreover, the immobilization technique helped restore microbial activity under low temperature, promoting the satisfactory nitrogen removal performance of recovered microorganism to be rebuilt by feeding nutrient solution. Overall, the long-term SND process and maintaining effective biofilm activity can be established in the compact biofilm reactor through several improving alternatives.
净化槽作为一种紧凑型生物膜反应器已被广泛应用于去除农村污水中的有机物，但它在脱氮方面的潜力却很少被讨论。本研究开发了一种实验室规模的紧凑型生物膜反应器，通过分步进料、间歇曝气和固定化技术实现高效的氮去除性能。结果表明，通过在高 C/N 比为 2 的合成废水中以及实际污水中进料，可以实现高效的同步硝化反硝化（SND）过程，主要归因于分步进料。对于合成废水和实际污水，总无机氮的平均去除效率分别达到了 72.7%和 63.3%。除了分步进料操作外，还采用间歇曝气来增强 SND，这使得紧凑型生物膜反应器的水力行为遵循完全搅拌罐反应器的模型。高通量测序分析表明，在高 C/N 比下，Sphaerotilus 成为优势属，相对丰度为 30.29%，硝化菌没有受到很大抑制。此外，固定化技术有助于在低温下恢复微生物活性，通过添加营养液促进恢复微生物的令人满意的氮去除性能得以重建。总的来说，通过几种改进的方法，可以在紧凑型生物膜反应器中建立长期的 SND 过程并保持有效的生物膜活性。
