By combining sequencing batch reactor (SBR) activated sludge process and constructed wetland (CW), this study is to achieve the domestic wastewater treatment. Our purpose was to determine the optimum operating paramet...By combining sequencing batch reactor (SBR) activated sludge process and constructed wetland (CW), this study is to achieve the domestic wastewater treatment. Our purpose was to determine the optimum operating parameters of the combined process. The process involved advantages and shortages of SBR and CW. Under normal temperature, the 3rd cycle (SBR’s operation cycle is 8 h: inflow for 1 h, limited aeration for 3 h, sediment for 1 h, outflow for 1 h, and idling for 2 h; CW’s hydraulic retention time (HRT) is 24.8 h and hydraulic loading is 24.5 m3/m2 d) was the best cyclic mode. The effluents can meet the standard GB/T18921-2002: "The reuse of urban recycling water: water quality standard for scenic environment use". In the 3rd cycle, the efficiency of CW was the maximum, and energy consumption of SBR was the minimum. Under the condition of low dissolved oxygen, the removing efficiency of chemical oxygen demand (COD) and ammonia was not affected obviously. Simultaneously, nitrification and denitrification phenomena occured and phosphorus was absorbed obviously.展开更多
Soil microbes are one of the most important determinants of allelopathic effects in the field. However, most studies testing the role of allelopathy in biological invasions did not consider the roles of soil microbes....Soil microbes are one of the most important determinants of allelopathic effects in the field. However, most studies testing the role of allelopathy in biological invasions did not consider the roles of soil microbes. Here we tested the hypothesis that soil microbes which can degrade allelochemicals may accumulate in soils over time by adaptation and therefore increase the degradation of allelochemicals and alleviate the allelopathic effects in biological invasions. As expected, soil microbes signifi- cantly decreased the allelopathic effects of leaf leachates of eight in the nine invasive plant species studied. In addition, Ageratina adenophora showed lower allelopathic effects in soil with long or intermediately invasion history than those in soil with short invasion history. The two main allelo- chemicals of the invader were degraded more rapidly with increasing invasion history in the soil. Correspondingly,biomass and activity of the soil microbes were higher in the soils with long invasion history than in that with short invasion history. Our results indicate that soil microbes may graduaUy adapt to the allelochemicals of Ageratina and alleviate its allelopathic effects and thus support the above hypothesis. It is necessary to consider the effects of soil microbes when testing the roles of allelopathy or the novel weapons hypothesis in biological invasions.展开更多
基金Funded by Sustainable Water Management Improves Tomorrow’s City’s Health (SWITCH018530)
文摘By combining sequencing batch reactor (SBR) activated sludge process and constructed wetland (CW), this study is to achieve the domestic wastewater treatment. Our purpose was to determine the optimum operating parameters of the combined process. The process involved advantages and shortages of SBR and CW. Under normal temperature, the 3rd cycle (SBR’s operation cycle is 8 h: inflow for 1 h, limited aeration for 3 h, sediment for 1 h, outflow for 1 h, and idling for 2 h; CW’s hydraulic retention time (HRT) is 24.8 h and hydraulic loading is 24.5 m3/m2 d) was the best cyclic mode. The effluents can meet the standard GB/T18921-2002: "The reuse of urban recycling water: water quality standard for scenic environment use". In the 3rd cycle, the efficiency of CW was the maximum, and energy consumption of SBR was the minimum. Under the condition of low dissolved oxygen, the removing efficiency of chemical oxygen demand (COD) and ammonia was not affected obviously. Simultaneously, nitrification and denitrification phenomena occured and phosphorus was absorbed obviously.
基金We are grateful to Da-Wen Li and Ailaoshan Station for Subtropical Forest Ecosystem Studies, Chinese Academy of Sciences for field assistance. This work was supported by the National Natural Science Foundation of China （31100410, 31470575 and 30830027）, the National Key Technology R＆D Program of China （2011BAD30B00）, and Chinese Academy Science 135 Program （XTBG-T01, F01）.
文摘Soil microbes are one of the most important determinants of allelopathic effects in the field. However, most studies testing the role of allelopathy in biological invasions did not consider the roles of soil microbes. Here we tested the hypothesis that soil microbes which can degrade allelochemicals may accumulate in soils over time by adaptation and therefore increase the degradation of allelochemicals and alleviate the allelopathic effects in biological invasions. As expected, soil microbes signifi- cantly decreased the allelopathic effects of leaf leachates of eight in the nine invasive plant species studied. In addition, Ageratina adenophora showed lower allelopathic effects in soil with long or intermediately invasion history than those in soil with short invasion history. The two main allelo- chemicals of the invader were degraded more rapidly with increasing invasion history in the soil. Correspondingly,biomass and activity of the soil microbes were higher in the soils with long invasion history than in that with short invasion history. Our results indicate that soil microbes may graduaUy adapt to the allelochemicals of Ageratina and alleviate its allelopathic effects and thus support the above hypothesis. It is necessary to consider the effects of soil microbes when testing the roles of allelopathy or the novel weapons hypothesis in biological invasions.
