In this article,a steady-state mathematical model was developed and experimentally evaluated to inves- tigate the effect of influent flow distribution and volume ratios of anoxic and aerobic zones in each stage on the...In this article,a steady-state mathematical model was developed and experimentally evaluated to inves- tigate the effect of influent flow distribution and volume ratios of anoxic and aerobic zones in each stage on the to- tal nitrogen concentration of the effluent in the step-feed biological nitrogen removal process.Unlike the previous modeling methods,this model can be used to calculate the removal rates of ammonia and nitrate in each stage and thereby predict the concentrations of ammonia,nitrate,and total nitrogen in the effluent.To verify the simulation results,pilot-scale experimental studies were carried out in a four-stage step feed process.Good correlations were achieved between the measured data and the simulation results,which proved the validity of the developed model. The sensitivity of the model predictions was analyzed.After verification of the validity,the step feed process was optimally operated for five months using the model and the criteria developed for the design and operation.During the pilot-scale experimental period,the effluent total nitrogen concentrations were all below 5mg·L -1 ,with more than 90%removal efficiency.展开更多
Some Tibetan villages in Shenzha county, Tibet were chosen as typical Tibetan communities in China. Attitudes and perceptions towards Tibetan community participation in ecotourism were analyzed using face to face inte...Some Tibetan villages in Shenzha county, Tibet were chosen as typical Tibetan communities in China. Attitudes and perceptions towards Tibetan community participation in ecotourism were analyzed using face to face interviews. Most residents supported the development of ecotourism. They are willing to engage in ecotourism projects and accept ecotourism education and training, and expect that the government provides opportunities for them to participate in making ecotourism decisions. Most residents believed that ecotourism promotes local economies and social development, and enhances the ability and quality of local residents while improving their environmental consciousness. However, some residents were concerned that ecotourism may destroy local natural environments and Tibetan folk customs and culture. The level of community participation in ecotourism development is only in its infancy in Shenzha, but there is strong potential. The chief participatory approaches of ecotourism development for most residents were providing labor and catering services and commodities for tourism, and Tibetan performance singing and dancing. Limiting factors include language, a shortage of knowledge and skills, and poor ecotourism infrastructure. Most residents had little confidence that the government was willing to support them to participate in ecotourism. We put forward some mechanisms to enhance the level of community participation in ecotourism in this important region.展开更多
基金Supported by the National Natural Science Foundation Key International Cooperation Project of China （No.50521140075）, the 863 Attached Financial Supporting Item of Beijing Municipal Science and Technology Commission （No.Z0005186040421） and the Doctor Subject Soecial Financial Supporfing Item of High College （No.20060005002）.
文摘In this article,a steady-state mathematical model was developed and experimentally evaluated to inves- tigate the effect of influent flow distribution and volume ratios of anoxic and aerobic zones in each stage on the to- tal nitrogen concentration of the effluent in the step-feed biological nitrogen removal process.Unlike the previous modeling methods,this model can be used to calculate the removal rates of ammonia and nitrate in each stage and thereby predict the concentrations of ammonia,nitrate,and total nitrogen in the effluent.To verify the simulation results,pilot-scale experimental studies were carried out in a four-stage step feed process.Good correlations were achieved between the measured data and the simulation results,which proved the validity of the developed model. The sensitivity of the model predictions was analyzed.After verification of the validity,the step feed process was optimally operated for five months using the model and the criteria developed for the design and operation.During the pilot-scale experimental period,the effluent total nitrogen concentrations were all below 5mg·L -1 ,with more than 90%removal efficiency.
基金National Science and Technology Support Plan (No. 2009BAH50B01-03) National Natural Science Foundation Item (No.41171435)
文摘Some Tibetan villages in Shenzha county, Tibet were chosen as typical Tibetan communities in China. Attitudes and perceptions towards Tibetan community participation in ecotourism were analyzed using face to face interviews. Most residents supported the development of ecotourism. They are willing to engage in ecotourism projects and accept ecotourism education and training, and expect that the government provides opportunities for them to participate in making ecotourism decisions. Most residents believed that ecotourism promotes local economies and social development, and enhances the ability and quality of local residents while improving their environmental consciousness. However, some residents were concerned that ecotourism may destroy local natural environments and Tibetan folk customs and culture. The level of community participation in ecotourism development is only in its infancy in Shenzha, but there is strong potential. The chief participatory approaches of ecotourism development for most residents were providing labor and catering services and commodities for tourism, and Tibetan performance singing and dancing. Limiting factors include language, a shortage of knowledge and skills, and poor ecotourism infrastructure. Most residents had little confidence that the government was willing to support them to participate in ecotourism. We put forward some mechanisms to enhance the level of community participation in ecotourism in this important region.
