Based on the achievement of local ecological geochemical survey,the selenium in surface layer soil of Zhangqiu green Chinese onion within production area is systematically studied in this study.And the ecological geoc...Based on the achievement of local ecological geochemical survey,the selenium in surface layer soil of Zhangqiu green Chinese onion within production area is systematically studied in this study.And the ecological geochemical characters of selenium both in surface layer soil and in green Chinese onions are analyzed,and the relationship between the selenium in plant and soil is discussed.The results show that soil in Zhangqiu is rich in selenium,and it is suitable to develop the selenium-rich green Chinese onion products.展开更多
Bionitrification is considered to be a potential source of nitrous oxide （N2O） emissions, which are produced as a by-product during the nitrogen removal process. To investigate the production of N2O during the proce...Bionitrification is considered to be a potential source of nitrous oxide （N2O） emissions, which are produced as a by-product during the nitrogen removal process. To investigate the production of N2O during the process of nitrogen removal via nitrite, a granular sludge was studied using a labscale sequence batch reactor operated with real-time control. The total production of N2O generated during the nitrification and denitrification processes were 1.724 mg/L and 0.125 mg/L, respectively, demonstrating that N2O is produced during both processes, with the nitrification phase generating larger amount. In addition, due to the NEO-N mass/oxidized ammonia mass ratio, it can be concluded that nitrite accumulation has a positive influence on N2O emissions. Results obtained from PCRDGGE analysis demonstrate that a specific Nitrosomonas microorganism is related to N2O emission.展开更多
Nitrous oxide（N_2O） is a potent greenhouse gas that can be emitted during biological nitrogen removal. N_2O emission was examined in a multiple anoxic and aerobic process at the aeration rates of 600 m L/min sequenc...Nitrous oxide（N_2O） is a potent greenhouse gas that can be emitted during biological nitrogen removal. N_2O emission was examined in a multiple anoxic and aerobic process at the aeration rates of 600 m L/min sequencing batch reactor（SBRL） and 1200 m L/min（SBRH）.The nitrogen removal percentage was 89% in SBRLand 71% in SBRH, respectively. N_2O emission mainly occurred during the aerobic phase, and the N_2O emission factor was 10.1%in SBRLand 2.3% in SBRH, respectively. In all batch experiments, the N_2O emission potential was high in SBRLcompared with SBRH. In SBRL, with increasing aeration rates, the N_2O emission factor decreased during nitrification, while it increased during denitrification and simultaneous nitrification and denitrification（SND）. By contrast, in SBRHthe N_2O emission factor during nitrification, denitrification and SND was relatively low and changed little with increasing aeration rates. The microbial competition affected the N_2O emission during biological nitrogen removal.展开更多
基金Supported by China Geological Survey Bureau Project(1212010310306)~~
文摘Based on the achievement of local ecological geochemical survey,the selenium in surface layer soil of Zhangqiu green Chinese onion within production area is systematically studied in this study.And the ecological geochemical characters of selenium both in surface layer soil and in green Chinese onions are analyzed,and the relationship between the selenium in plant and soil is discussed.The results show that soil in Zhangqiu is rich in selenium,and it is suitable to develop the selenium-rich green Chinese onion products.
基金supported by the National Natural Science Foundation of China(No.21177033)the Research Fund for the Doctoral Program of Higher Education,Ministry of Education of China(No.20092302110059)the Program for Famous Teachers of Northeast Forestry University(No.PFT-1213-22)
文摘Bionitrification is considered to be a potential source of nitrous oxide （N2O） emissions, which are produced as a by-product during the nitrogen removal process. To investigate the production of N2O during the process of nitrogen removal via nitrite, a granular sludge was studied using a labscale sequence batch reactor operated with real-time control. The total production of N2O generated during the nitrification and denitrification processes were 1.724 mg/L and 0.125 mg/L, respectively, demonstrating that N2O is produced during both processes, with the nitrification phase generating larger amount. In addition, due to the NEO-N mass/oxidized ammonia mass ratio, it can be concluded that nitrite accumulation has a positive influence on N2O emissions. Results obtained from PCRDGGE analysis demonstrate that a specific Nitrosomonas microorganism is related to N2O emission.
基金supported by the Shenzhen Overseas High-Level Talents Innovation Funds Peacock Plan Project (No. KQCX20120814155347053)the National Natural Science Foundation of China (No. 51108242)
文摘Nitrous oxide（N_2O） is a potent greenhouse gas that can be emitted during biological nitrogen removal. N_2O emission was examined in a multiple anoxic and aerobic process at the aeration rates of 600 m L/min sequencing batch reactor（SBRL） and 1200 m L/min（SBRH）.The nitrogen removal percentage was 89% in SBRLand 71% in SBRH, respectively. N_2O emission mainly occurred during the aerobic phase, and the N_2O emission factor was 10.1%in SBRLand 2.3% in SBRH, respectively. In all batch experiments, the N_2O emission potential was high in SBRLcompared with SBRH. In SBRL, with increasing aeration rates, the N_2O emission factor decreased during nitrification, while it increased during denitrification and simultaneous nitrification and denitrification（SND）. By contrast, in SBRHthe N_2O emission factor during nitrification, denitrification and SND was relatively low and changed little with increasing aeration rates. The microbial competition affected the N_2O emission during biological nitrogen removal.
