A B S T R A C TAerobic granular sludge (AGS) was imbedded in agar and stored at 4 C for 30 days, and then the stored granules were recovered in a sequencing batch reactor fed real wastewater within 11 days. Variations in microbial community compositions were investigated during dry storage and recovery of AGS, aiming to elucidate the mechanism of granular stability loss and recovery. The storage and recovery of AGS involved microbial community evolution. The dominant bacterial genera of the mature AGS were Zoogloea (relative abundance of 22.39%), Thauera (16.03%) and Clostridium_sensu_stricto (11.17%), and those of the stored granules were Acidovorax (26.79%), Macellibacteroides (12.83%) and Pseudoxanthomonas (5.69%), respectively. However, the dominant genera were Streptococcus (43.64%), Clostridium_sensu_stricto (12.3.6%) and Lactococcus (11.47%) in the recovered AGS. Methanogens were always the dominant archaeal species in mature AGS (93.01%), stored granules (99.99%) and the recovered AGS (94.84%). Facultative anaerobes and anaerobes proliferated and dominated in the stored granules, and their metabolic activities gradually led to granular structure destruction and property deterioration. However, the stored granules served as carriers for the microbes originated from the real septic tank wastewater during recovery. They proliferated rapidly and secreted a large number of extracellular polymeric substances which helped to recover the granular structure in 11 days.

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The highest level of epidemic prevention and control is precise prevention and control. That is to say, through rapid flow adjustment, we can track down all the close contacts and sub-close contacts, and only isolate them without affecting the work and life of others. Of course, it is difficult to achieve absolute precision prevention and control, so how to measure the degree of precision prevention and control in a region with a quantitative method. How to achieve the balance between security, efficiency, and economy under the abnormal background. From the perspective of safety, the prevention and control of the COVID-19 epidemic are still in a critical period. Once it is not carefully controlled, it may still cause secondary transmission, which will bring huge losses to the city's epidemic prevention work and the safety of residents' lives and property. Therefore, in order to immediately feedback on potential infectious sources, we created the fusion of FFR and SWF algorithms to expand the frequency capacity. The supervisors of large business districts can ensure that the frequency is distributed among as many groups as possible through the greater capacity to improve the information inspection mechanism.

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