The combination of preozonation and subsequent biological granular activated carbon （O3/BAC） filtration is well known as a promising method for the removal of many pollutants. Temperature and nutrients are the domin...The combination of preozonation and subsequent biological granular activated carbon （O3/BAC） filtration is well known as a promising method for the removal of many pollutants. Temperature and nutrients are the dominant factors in external conditions to influence the biological communities. To explore the influence of preozonation under low temperature, the factors such as dissolved oxygen （DO）, dissolved organic carbon （DOC） and NH4^＋-N were analyzed from the sampling ports every week; triphenyl tetrazolium ehloride-dehydrogenase activity （TTC-DHA） and the nitrifying activity were detected along the bed height ofbiofilter at four levels （10. 40. 70 and i 10 cm） on the 90th, 110th, and 130th day; ~nicrobial community, based on 16S rRNA gene-denaturing gradient gel electrophoresis （DGGE）, was monitored on the 130th day of the operation. The observed microbial property showed that preozonation had a positive influence on bioactivity, biomass and nitrifying activity. Community analysis showed no significant difference on the biodiversity of nitrifying bacteria between the parallel filters in the inlet end based on the method employed. This result showed that biofilters＇ performance is not correlated well with microbial biodiversity. The elevated functionality in O3/BAC filters can be a result of increased microbial activity, which was promoted by preozonation.展开更多
Observational evidence suggests that mask-wearing mitigates transmission of COVID-19;at the same time high respiratory resistance leads to an unwillingness to wear masks.This paper proposed a respiratory drive structu...Observational evidence suggests that mask-wearing mitigates transmission of COVID-19;at the same time high respiratory resistance leads to an unwillingness to wear masks.This paper proposed a respiratory drive structure to reduce the air resistance of a mask.This structure provides different shapes during expiration and inspiration while focusing on filtering dust,bacteria,or viruses.Meanwhile,the assembled system on the mask can be disassembled and replaced.Then porous media simulation is used to verify the model effect.Experimental results of a new mask show that the ventilation resistance is reduced by 20%,and the bacterial filtration efficiency meets the requirements of YY 0469–2011.展开更多
文摘The combination of preozonation and subsequent biological granular activated carbon （O3/BAC） filtration is well known as a promising method for the removal of many pollutants. Temperature and nutrients are the dominant factors in external conditions to influence the biological communities. To explore the influence of preozonation under low temperature, the factors such as dissolved oxygen （DO）, dissolved organic carbon （DOC） and NH4^＋-N were analyzed from the sampling ports every week; triphenyl tetrazolium ehloride-dehydrogenase activity （TTC-DHA） and the nitrifying activity were detected along the bed height ofbiofilter at four levels （10. 40. 70 and i 10 cm） on the 90th, 110th, and 130th day; ~nicrobial community, based on 16S rRNA gene-denaturing gradient gel electrophoresis （DGGE）, was monitored on the 130th day of the operation. The observed microbial property showed that preozonation had a positive influence on bioactivity, biomass and nitrifying activity. Community analysis showed no significant difference on the biodiversity of nitrifying bacteria between the parallel filters in the inlet end based on the method employed. This result showed that biofilters＇ performance is not correlated well with microbial biodiversity. The elevated functionality in O3/BAC filters can be a result of increased microbial activity, which was promoted by preozonation.
基金the Project of Establishing a Base for Training Interdisciplinary Innovative Talents with Practice at Shanghai Jiao Tong University。
文摘Observational evidence suggests that mask-wearing mitigates transmission of COVID-19;at the same time high respiratory resistance leads to an unwillingness to wear masks.This paper proposed a respiratory drive structure to reduce the air resistance of a mask.This structure provides different shapes during expiration and inspiration while focusing on filtering dust,bacteria,or viruses.Meanwhile,the assembled system on the mask can be disassembled and replaced.Then porous media simulation is used to verify the model effect.Experimental results of a new mask show that the ventilation resistance is reduced by 20%,and the bacterial filtration efficiency meets the requirements of YY 0469–2011.
