This paper deals with the procedure and methodology which can be used to select the optimal treatment and disposal technology of municipal solid waste （MSW）, and to provide practical and effective technical support ...This paper deals with the procedure and methodology which can be used to select the optimal treatment and disposal technology of municipal solid waste （MSW）, and to provide practical and effective technical support to policy-making, on the basis of study on solid waste management status and development trend in China and abroad. Focusing on various treatment and disposal technologies and processes of MSW, this study established a Monte-Carlo mathematical model of cost minimization for MSW handling subjected to environmental constraints. A new method of element stream （such as C, H, O, N, S） analysis in combination with economic stream analysis of MSW was developed. By following the streams of different treatment processes consisting of various techniques from generation, separation, transfer, transport, treatment, recycling and disposal of the wastes, the element constitution as well as its economic distribution in terms of possibility functions was identified. Every technique step was evaluated economically. The Mont-Carlo method was then conducted for model calibration. Sensitivity analysis was also carried out to identify the most sensitive factors. Model calibration indicated that landfill with power generation of landfill gas was economically the optimal technology at the present stage under the condition of more than 58% of C, H, O, N, S going to landfill. Whether or not to generate electricity was the most sensitive factor. If landfilling cost increases, MSW separation treatment was recommended by screening first followed with incinerating partially and composting partially with residue landfilling. The possibility of incineration model selection as the optimal technology was affected by the city scale. For big cities and metropolitans with large MSW generation, possibility for constructing large-scale incineration facilities increases, whereas, for middle and small cities, the effectiveness of incinerating waste decreases.展开更多
This study aimed to determine the waste that occurs in activities from receiving to delivering of finished products that can result in delays in the delivery of audio to Japan.The waste identified is limited to activi...This study aimed to determine the waste that occurs in activities from receiving to delivering of finished products that can result in delays in the delivery of audio to Japan.The waste identified is limited to activities in the finished goods warehouse.The problem that occurs is the delay in product delivery,because the product is not ready to be delivered so that it causes delays.The lean approach is used to reduce waste in the overall work process activities in the finished goods warehouse.Waste identification was performed through the 7 waste approach.Process Activity Mapping is one of the tools of VALSAT,and is looking for critical waste to find the root cause of waste.Delay can be minimized by making improvements to the layout of the warehouse and routine inspection of goods transporters.Companies should use lean to reduce the waste that occurs so there is no delay in the delivery of audio products.展开更多
Arsenic （As） pollutants generated by human activities in karst areas flow into subterranean streams and contaminate groundwater easily because of the unique hydrogeological characteristics of karst areas. To elucida...Arsenic （As） pollutants generated by human activities in karst areas flow into subterranean streams and contaminate groundwater easily because of the unique hydrogeological characteristics of karst areas. To elucidate the reaction mechanisms of arsenic in karst subterranean streams, physical-chemical analysis was conducted by an inductively coupled plasma mass spectrometer and an X-ray fluorescence spectrometer. The results show that inorganic species account for most of the total arsenic, whereas organic arsenic is not detected or occurs in infinitesimal amounts. As（III） accounts for 51.0% ± 9.9% of the total inorganic arsenic. Arsenic attenuation occurs and the attenuation rates of total As, As（III） and As（V） in the Lihu subterranean stream are 51%, 36% and 59%, respectively. To fully explain the main geochemical factors influencing arsenic attenuation, SPSS 13.0 and CANOCO 4.5 bundled with CanoDraw for Windows were used for simple statistical analysis and redundancy analysis （RDA）. Eight main factors, i.e., sediment iron （SFe）, sediment aluminum （SAI）, sediment calcium （SCa）, sediment organic matter （SOM）, sediment manganese （SMn）, water calcium （WCa^2＋）, water magnesium （WMg^2＋）, and water bicarbonate ion （WILCOX） were extracted from thirteen indicators. Their impacts on arsenic content rank as： SFe〉SCa〉WCa^2＋〉SAl〉wHCO3^-〉SMn〉SOM〉WMg^2＋. Of these factors, SFe, SAl, SCa, SOM, SMn, WMg^2＋ and WCa＆2＋ promote arsenic attenuation, whereas WHCO3^- inhibits it. Further investigation revealed that the redox potential （Eh） and pH are adverse to arsenic removal. The dramatic distinction between karst and non-karst terrain is that calcium and bicarbonate are the primary factors influencing arsenic migration in karst areas due to the high calcium concentration and alkalinity of karst water.展开更多
The effects of three factors （i.e., drop height h, hopper outlet diameter do, and material temperature T] on the dust generation rate derived from a free falling particle stream were investigated via filll factorial ...The effects of three factors （i.e., drop height h, hopper outlet diameter do, and material temperature T] on the dust generation rate derived from a free falling particle stream were investigated via filll factorial experiments. The correlation between the three factors and dust generation rate was also analysed. Results show that Tand h affect the first fugitive dust rate largely, whereas the second fugitive dust rate is mainly dominated by h and do. Through analysing the first fugitive dust percentage data, it is found that h and T should be considered first for higher temperatures and lower flow rates, whereas h and do can be considered under contrasting conditions, and h should be controlled in the remaining two sets of conditions. Relationships between the influencing factors and total and first fugitive dust rates were developed via multiple regression to quantify the dust emission rates for different contact surfaces （rigid or water）.展开更多
基金Project Supported by Tsinghua Research Foundation (No. Jc2003010).
文摘This paper deals with the procedure and methodology which can be used to select the optimal treatment and disposal technology of municipal solid waste （MSW）, and to provide practical and effective technical support to policy-making, on the basis of study on solid waste management status and development trend in China and abroad. Focusing on various treatment and disposal technologies and processes of MSW, this study established a Monte-Carlo mathematical model of cost minimization for MSW handling subjected to environmental constraints. A new method of element stream （such as C, H, O, N, S） analysis in combination with economic stream analysis of MSW was developed. By following the streams of different treatment processes consisting of various techniques from generation, separation, transfer, transport, treatment, recycling and disposal of the wastes, the element constitution as well as its economic distribution in terms of possibility functions was identified. Every technique step was evaluated economically. The Mont-Carlo method was then conducted for model calibration. Sensitivity analysis was also carried out to identify the most sensitive factors. Model calibration indicated that landfill with power generation of landfill gas was economically the optimal technology at the present stage under the condition of more than 58% of C, H, O, N, S going to landfill. Whether or not to generate electricity was the most sensitive factor. If landfilling cost increases, MSW separation treatment was recommended by screening first followed with incinerating partially and composting partially with residue landfilling. The possibility of incineration model selection as the optimal technology was affected by the city scale. For big cities and metropolitans with large MSW generation, possibility for constructing large-scale incineration facilities increases, whereas, for middle and small cities, the effectiveness of incinerating waste decreases.
文摘This study aimed to determine the waste that occurs in activities from receiving to delivering of finished products that can result in delays in the delivery of audio to Japan.The waste identified is limited to activities in the finished goods warehouse.The problem that occurs is the delay in product delivery,because the product is not ready to be delivered so that it causes delays.The lean approach is used to reduce waste in the overall work process activities in the finished goods warehouse.Waste identification was performed through the 7 waste approach.Process Activity Mapping is one of the tools of VALSAT,and is looking for critical waste to find the root cause of waste.Delay can be minimized by making improvements to the layout of the warehouse and routine inspection of goods transporters.Companies should use lean to reduce the waste that occurs so there is no delay in the delivery of audio products.
基金supported by the Basic Scientific Research Fund of Karst Geological Institute (No. 2012012)the Natural Science Fund Project of Guangxi (Nos. 2013GXNSFBA019218, 2013GXNSFBAO19217)the Project of the China Geological Survey (Nos. 12120113052500, 12120113005200)
文摘Arsenic （As） pollutants generated by human activities in karst areas flow into subterranean streams and contaminate groundwater easily because of the unique hydrogeological characteristics of karst areas. To elucidate the reaction mechanisms of arsenic in karst subterranean streams, physical-chemical analysis was conducted by an inductively coupled plasma mass spectrometer and an X-ray fluorescence spectrometer. The results show that inorganic species account for most of the total arsenic, whereas organic arsenic is not detected or occurs in infinitesimal amounts. As（III） accounts for 51.0% ± 9.9% of the total inorganic arsenic. Arsenic attenuation occurs and the attenuation rates of total As, As（III） and As（V） in the Lihu subterranean stream are 51%, 36% and 59%, respectively. To fully explain the main geochemical factors influencing arsenic attenuation, SPSS 13.0 and CANOCO 4.5 bundled with CanoDraw for Windows were used for simple statistical analysis and redundancy analysis （RDA）. Eight main factors, i.e., sediment iron （SFe）, sediment aluminum （SAI）, sediment calcium （SCa）, sediment organic matter （SOM）, sediment manganese （SMn）, water calcium （WCa^2＋）, water magnesium （WMg^2＋）, and water bicarbonate ion （WILCOX） were extracted from thirteen indicators. Their impacts on arsenic content rank as： SFe〉SCa〉WCa^2＋〉SAl〉wHCO3^-〉SMn〉SOM〉WMg^2＋. Of these factors, SFe, SAl, SCa, SOM, SMn, WMg^2＋ and WCa＆2＋ promote arsenic attenuation, whereas WHCO3^- inhibits it. Further investigation revealed that the redox potential （Eh） and pH are adverse to arsenic removal. The dramatic distinction between karst and non-karst terrain is that calcium and bicarbonate are the primary factors influencing arsenic migration in karst areas due to the high calcium concentration and alkalinity of karst water.
文摘The effects of three factors （i.e., drop height h, hopper outlet diameter do, and material temperature T] on the dust generation rate derived from a free falling particle stream were investigated via filll factorial experiments. The correlation between the three factors and dust generation rate was also analysed. Results show that Tand h affect the first fugitive dust rate largely, whereas the second fugitive dust rate is mainly dominated by h and do. Through analysing the first fugitive dust percentage data, it is found that h and T should be considered first for higher temperatures and lower flow rates, whereas h and do can be considered under contrasting conditions, and h should be controlled in the remaining two sets of conditions. Relationships between the influencing factors and total and first fugitive dust rates were developed via multiple regression to quantify the dust emission rates for different contact surfaces （rigid or water）.
