Themulti-soil-layering(MSL)systems is an emerging solution for environmentally-friendly and cost-effective treatment of decentralized rural domestic wastewater.However,the role of the seemingly simple permeable layer ...Themulti-soil-layering(MSL)systems is an emerging solution for environmentally-friendly and cost-effective treatment of decentralized rural domestic wastewater.However,the role of the seemingly simple permeable layer has been overlooked,potentially holding the breakthroughs or directions to addressing suboptimal nitrogen removal performance in MSL systems.In this paper,the mechanism among diverse substrates(zeolite,green zeolite and biological ceramsite)coupled microorganisms in different systems(activated bacterial powder and activated sludge)for rural domestic wastewater purification was investigated.The removal efficiencies performed by zeolite coupled with microorganisms within 3 days were 93.8%for COD,97.1%for TP,and 98.8%for NH_(4)^(+)-N.Notably,activated sludge showed better nitrification and comprehensive performance than specialized nitrifying bacteria powder.Zeolite attained an impressive 89.4%NH4+-N desorption efficiency,with a substantive fraction of NH_(4)^(+)-N manifesting as exchanged ammonium.High-throughput 16S rRNA gene sequencing revealed that aerobic and parthenogenetic anaerobic bacteria dominated the reactor,with anaerobic bacteria conspicuously absent.And the heterotrophic nitrificationaerobic denitrification(HN-AD)process was significant,with the presence of denitrifying phosphorus-accumulating organisms(DPAOs)for simultaneous nitrogen and phosphorus removal.This study not only raises awareness about the importance of the permeable layer and enhances comprehension of the HN-AD mechanism in MSL systems,but also provides valuable insights for optimizing MSL system construction,operation,and rural domestic wastewater treatment.展开更多
Concentrated turtle aquaculture effluent poses an environmental threat to water bodies, and therefore needs to be treated prior to disposal. This study was conducted to assess the effect of multi-soil-layer（MSL） sys...Concentrated turtle aquaculture effluent poses an environmental threat to water bodies, and therefore needs to be treated prior to disposal. This study was conducted to assess the effect of multi-soil-layer（MSL） systems treating turtle aquaculture effluent with adding different amounts of sludge. Four MSL systems were constructed with dry weight ratios of sludge with 0%, 5%, 10%, and 20%（MSL 1, MSL 2, MSL 3, and MSL 4, respectively）. The turtle aquaculture effluent had an average chemical oxygen demand（COD）, ammonia nitrogen（NH4^＋-N） and total nitrogen（TN） concentration of 288.4, 213.4, and 252.0 mg/L, respectively. The COD/TN（C/N） ratio was 1.2. The results showed that the four MSL systems could effectively treat the COD, NH4^＋-N, and TN, and MSL 4 showed significantly improved NH4^＋-N removal efficiency, suggesting the potential of sludge addition to improve the turtle aquaculture effluent treatment. The average COD, TN, and NH4^＋-N removal efficiencies of MSL 4 were 70.3%, 66.5%, and 72.7%, respectively. To further interpret the contribution of microorganisms to the removal, the microbial community compositions and diversities of the four MSL systems were measured. Comparisons of the denaturing gradient gel electrophoresis（DGGE） profiles revealed that the amount of nitrifying bacteria and diversity in MSL 4 were higher than those in the other three systems. We concluded that adding 20% of sludge improved the NH4^＋-N removal and stability of the system for nitrification, due to the enrichment of the nitrifying bacteria in MSL 4.展开更多
The long-term time series analysis of the SST (sea surface temperature) in the Eastern Equatorial Pacific Ocean and the monthly MSL (mean sea level) in the tropical Pacific Ocean is conducted. Their quasiperiodic and ...The long-term time series analysis of the SST (sea surface temperature) in the Eastern Equatorial Pacific Ocean and the monthly MSL (mean sea level) in the tropical Pacific Ocean is conducted. Their quasiperiodic and low-frequency oscillation features are revealed. The significant periods of low-frequency fluctuations for monthly MSL in the area of 20°N-20° S are between 43. 5 months and 50. 0 months, approximating closely to 47. 6 months which is the significant period of SST in the Eastern Equatorial Pacific Ocean. From the results of space-spectral analysis, the low-frequency fluctations of monthly MSL in the tropical Pacific Ocean appear to have a anticlockwise circularly-propagating pattern, which is, the Eastern Pacific Ocean (off-shore of Mexico) →the area of NEC (North Equatorial Current) →the Western Equatorial Pacific Ocean→the area of NECC (North Equatorial Counter-Current)→the Eastern Equatorial Pacific Ocean. The phases of the pattern correspond to those of El Nino cycle. On the basis of the above results,a basic model is established with stepwise-regression method, which can forecast El Nino events by the variations of monthly MSL at a few stations in the tropical Pacific Ocean 4 months ahead. The correlation coefficient between the forecasted series and the observed one is 0. 89.展开更多
MSL(male specific lethal)复合体作为调节果蝇剂量补偿的关键元件,在非整倍体基因表达调控过程中发挥了重要作用.为深入探究非整倍体胚胎发育过程的分子调控机制,运用TSA-FISH(tyramide signal amplificationfluorescence in situ hybr...MSL(male specific lethal)复合体作为调节果蝇剂量补偿的关键元件,在非整倍体基因表达调控过程中发挥了重要作用.为深入探究非整倍体胚胎发育过程的分子调控机制,运用TSA-FISH(tyramide signal amplificationfluorescence in situ hybridization)技术比较分析正常二倍体胚胎与常染色体三体胚胎中的MSL复合体组分基因表达模式,探究复合体重要组分在果蝇非整倍体胚胎不同时期的表达水平,以及亚细胞定位的变化.研究结果表明,在MSL复合体尚未组装的非整倍体胚胎发育早期,即母体表达阶段,多数复合体组分基因就已存在转录本水平上的差异,而这种表达差异主要源自于母体的非单倍体配子.随着发育的进行,染色体片段的增加导致基因组内剂量平衡发生变化,由此产生的反式剂量效应将引发MSL复合体各组分表达水平的差异变化,而这种差异将持续作用于后续非整倍体胚胎发育的各个时期.展开更多
基金supported by the National Natural Science Foundation of China(No.42077163).
文摘Themulti-soil-layering(MSL)systems is an emerging solution for environmentally-friendly and cost-effective treatment of decentralized rural domestic wastewater.However,the role of the seemingly simple permeable layer has been overlooked,potentially holding the breakthroughs or directions to addressing suboptimal nitrogen removal performance in MSL systems.In this paper,the mechanism among diverse substrates(zeolite,green zeolite and biological ceramsite)coupled microorganisms in different systems(activated bacterial powder and activated sludge)for rural domestic wastewater purification was investigated.The removal efficiencies performed by zeolite coupled with microorganisms within 3 days were 93.8%for COD,97.1%for TP,and 98.8%for NH_(4)^(+)-N.Notably,activated sludge showed better nitrification and comprehensive performance than specialized nitrifying bacteria powder.Zeolite attained an impressive 89.4%NH4+-N desorption efficiency,with a substantive fraction of NH_(4)^(+)-N manifesting as exchanged ammonium.High-throughput 16S rRNA gene sequencing revealed that aerobic and parthenogenetic anaerobic bacteria dominated the reactor,with anaerobic bacteria conspicuously absent.And the heterotrophic nitrificationaerobic denitrification(HN-AD)process was significant,with the presence of denitrifying phosphorus-accumulating organisms(DPAOs)for simultaneous nitrogen and phosphorus removal.This study not only raises awareness about the importance of the permeable layer and enhances comprehension of the HN-AD mechanism in MSL systems,but also provides valuable insights for optimizing MSL system construction,operation,and rural domestic wastewater treatment.
基金supported by the Ministry of Environmental Protection of China(No.2010467014)the Science and Technology Key Plan of Huzhou(No.2011GN19),China
文摘Concentrated turtle aquaculture effluent poses an environmental threat to water bodies, and therefore needs to be treated prior to disposal. This study was conducted to assess the effect of multi-soil-layer（MSL） systems treating turtle aquaculture effluent with adding different amounts of sludge. Four MSL systems were constructed with dry weight ratios of sludge with 0%, 5%, 10%, and 20%（MSL 1, MSL 2, MSL 3, and MSL 4, respectively）. The turtle aquaculture effluent had an average chemical oxygen demand（COD）, ammonia nitrogen（NH4^＋-N） and total nitrogen（TN） concentration of 288.4, 213.4, and 252.0 mg/L, respectively. The COD/TN（C/N） ratio was 1.2. The results showed that the four MSL systems could effectively treat the COD, NH4^＋-N, and TN, and MSL 4 showed significantly improved NH4^＋-N removal efficiency, suggesting the potential of sludge addition to improve the turtle aquaculture effluent treatment. The average COD, TN, and NH4^＋-N removal efficiencies of MSL 4 were 70.3%, 66.5%, and 72.7%, respectively. To further interpret the contribution of microorganisms to the removal, the microbial community compositions and diversities of the four MSL systems were measured. Comparisons of the denaturing gradient gel electrophoresis（DGGE） profiles revealed that the amount of nitrifying bacteria and diversity in MSL 4 were higher than those in the other three systems. We concluded that adding 20% of sludge improved the NH4^＋-N removal and stability of the system for nitrification, due to the enrichment of the nitrifying bacteria in MSL 4.
文摘The long-term time series analysis of the SST (sea surface temperature) in the Eastern Equatorial Pacific Ocean and the monthly MSL (mean sea level) in the tropical Pacific Ocean is conducted. Their quasiperiodic and low-frequency oscillation features are revealed. The significant periods of low-frequency fluctuations for monthly MSL in the area of 20°N-20° S are between 43. 5 months and 50. 0 months, approximating closely to 47. 6 months which is the significant period of SST in the Eastern Equatorial Pacific Ocean. From the results of space-spectral analysis, the low-frequency fluctations of monthly MSL in the tropical Pacific Ocean appear to have a anticlockwise circularly-propagating pattern, which is, the Eastern Pacific Ocean (off-shore of Mexico) →the area of NEC (North Equatorial Current) →the Western Equatorial Pacific Ocean→the area of NECC (North Equatorial Counter-Current)→the Eastern Equatorial Pacific Ocean. The phases of the pattern correspond to those of El Nino cycle. On the basis of the above results,a basic model is established with stepwise-regression method, which can forecast El Nino events by the variations of monthly MSL at a few stations in the tropical Pacific Ocean 4 months ahead. The correlation coefficient between the forecasted series and the observed one is 0. 89.
文摘MSL(male specific lethal)复合体作为调节果蝇剂量补偿的关键元件,在非整倍体基因表达调控过程中发挥了重要作用.为深入探究非整倍体胚胎发育过程的分子调控机制,运用TSA-FISH(tyramide signal amplificationfluorescence in situ hybridization)技术比较分析正常二倍体胚胎与常染色体三体胚胎中的MSL复合体组分基因表达模式,探究复合体重要组分在果蝇非整倍体胚胎不同时期的表达水平,以及亚细胞定位的变化.研究结果表明,在MSL复合体尚未组装的非整倍体胚胎发育早期,即母体表达阶段,多数复合体组分基因就已存在转录本水平上的差异,而这种表达差异主要源自于母体的非单倍体配子.随着发育的进行,染色体片段的增加导致基因组内剂量平衡发生变化,由此产生的反式剂量效应将引发MSL复合体各组分表达水平的差异变化,而这种差异将持续作用于后续非整倍体胚胎发育的各个时期.
