为探究生物絮团适宜的保存温度，通过单因素实验设计，将絮团在常温(25 °C)、冷藏(4 °C)和冷冻(–20 °C)条件下分别密封保存了7、14、21和28 d。结果显示，随着保存时间的延长，絮团的硝化性能在3种温度保存条件下较初始硝化性能均有不同程度的下降。在4 °C保存28天的絮团中，氨氧化速率为(0.16±0.10) mg/(L·h)，显著高于25 °C条件下的(0.08±0.09) mg/(L·h)和-20 °C条件下的(0.01±0.09) mg/(L·h)，其中，-20 °C保存条件下的絮团在第7 天几乎丧失氨氧化活性，较初始氨氧化速率下降了99.52%。在第28 天，4 °C下保存的絮团亚硝态氮氧化速率为(0.19±0.03) mg/(L·h)，显著高于25 °C保存条件下的(0.10±0.05) mg/(L·h)和-20 °C保存条件下的(0.14±0.02) mg/(L·h)。显微观察的结果显示，25 °C保存条件下絮团结构松散，絮团的体积平均粒径由初始的(245.92±21.51) μm减小到第28天的(148.50±9.90) μm；在-20 °C保存条件下，絮团的体积平均粒径由(245.92±21.51) μm增大到(310.82±29.67) μm；4 °C保存条件下，絮团的形态结构和粒径均未受到显著变化。研究表明，4 °C的保存条件可作为生物絮团的保存温度。本研究为生物絮团适宜的保存温度和保存时间提供了参考依据，有利于生物絮团在实际生产中的保存和再使用。

This study aimed to determine the optimal storage temperature for bioflocs. A One-Way experimental design was employed, where bioflocs were stored at room temperature (25 °C), refrigerated (4 °C) and frozen (-20 °C) for periods of 7, 14, 21 and 28 d. The nitrification performance of bioflocs declined under all three conditions as storage time increased. After 28 d, the ammonia oxidation rate at 4 °C was (0.16±0.10) mg/(L·h), significantly higher than the rates at 25 °C (0.08±0.09) mg/(L·h) and -20 °C (0.01±0.09) mg/(L·h). Bioflocs stored at -20 °C had almost no ammonia oxidation activity by day 7, with a 99.52% reduction from the initial rate. The nitrite oxidation rate at 4 °C after 28 d was (0.19±0.03) mg/(L·h), which was significantly higher than that of bioflocs stored at 25 °C (0.10±0.05) mg/(L·h) and -20 °C (0.14±0.02) mg/(L·h). Microscopic observation revealed that of bioflocs stored at 25 °C became looser, with a decrease in volume average size from (245.92±21.51) μm to (148.50±9.90) μm by day 28. Conversely, bioflocs stored at -20 °C increased in size from (245.92±21.51) μm to (310.82±29.67) μm. No significant changes in structure or particle size were observed for bioflocs stored at 4 °C. In conclusion, a storage temperature of 4 °C is recommended for bioflocs. This study provides insights into appropriate storage conditions and duration, which can inform the storage and reuse of bioflocs in practical applications.

S 959

上海市科学技术委员会扬帆人才计划 (22YF1416400)；上海水产养殖工程技术研究中心能力提升项目 (19DZ2284300)