Unplanned urban population growth in developing countries such as Sri Lanka exert pressures on the sectors of water supply, sewage disposal, waste management, and surface drainage in the cities as well as their surrou...Unplanned urban population growth in developing countries such as Sri Lanka exert pressures on the sectors of water supply, sewage disposal, waste management, and surface drainage in the cities as well as their surrounding areas. The Mid-canal is considered the most polluted surface water body in the Kandy district of Sri Lanka and contributes significantly to pollution of the Mahaweli River. Health problems in the nearby population may well be associated with environmental degradation and related to deteriorated water quality. The overall objectives of this study were to identify the socio-economic status of the community settled along the Meda Ela banks, and to examine the current water quality status of the Meda Ela and possible impacts of the nearby residents on water quality. Additionally, we propose remedial measures concerning wastewater and solid waste disposal to improve environmental conditions in this area.展开更多
Constructed wetlands（CWs） have been successfully used for treating various wastewaters for decades and have been identified as a sustainable wastewater management option worldwide.However,the application of CW for w...Constructed wetlands（CWs） have been successfully used for treating various wastewaters for decades and have been identified as a sustainable wastewater management option worldwide.However,the application of CW for wastewater treatment in frigid climate presents special challenges.Wetland treatment of wastewater relies largely on biological processes,and reliable treatment is often a function of climate conditions.To date,the rate of adoption of wetland technology for wastewater treatment in cold regions has been slow and there are relatively few published reports on CW applications in cold climate.This paper therefore highlights the practice and applications of treatment wetlands in cold climate.A comprehensive review of the effectiveness of contaminant removal in different wetland systems including：（1） free water surface（FWS） CWs;（2） subsurface flow（SSF） CWs;and（3） hybrid wetland systems,is presented.The emphasis of this review is also placed on the influence of cold weather conditions on the removal efficacies of different contaminants.The strategies of wetland design and operation for performance intensification,such as the presence of plant,operational mode,effluent recirculation,artificial aeration and in-series design,which are crucial to achieve the sustainable treatment performance in cold climate,are also discussed.This study is conducive to further research for the understanding of CW design and treatment performance in cold climate.展开更多
Constructed wetlands（CWs） have been successfully used for treating various wastewaters for decades and have been identified as a sustainable wastewater management option for developing countries. With the goal of pr...Constructed wetlands（CWs） have been successfully used for treating various wastewaters for decades and have been identified as a sustainable wastewater management option for developing countries. With the goal of promoting sustainable engineered systems that support human well-being but are also compatible with sustaining natural（environmental）systems, the application of CWs has become more relevant. Such application is especially significant for developing countries with tropical climates, which are very conducive to higher biological activity and productivity, resulting in higher treatment efficiencies compared to those in temperate climates. This paper therefore highlights the practice,applications, and research of treatment wetlands under tropical and subtropical conditions since 2000. In the present review, removal of biochemical oxygen demand（BOD） and total suspended solid（TSS） was shown to be very efficient and consistent across all types of treatment wetlands. Hybrid systems appeared more efficient in the removal of total suspended solid（TSS）（91.3%）, chemical oxygen demand（COD）（84.3%）, and nitrogen（i.e.,80.7% for ammonium（NH）4-N, 80.8% for nitrate（NO）3-N, and 75.4% for total nitrogen（TN））as compared to other wetland systems. Vertical subsurface flow（VSSF） CWs removed TSS（84.9%）, BOD（87.6%）, and nitrogen（i.e., 66.2% for NH4-N, 73.3% for NO3-N, and 53.3% for TN）more efficiently than horizontal subsurface flow（HSSF） CWs, while HSSF CWs（69.8%）showed better total phosphorus（TP） removal compared to VSSF CWs（60.1%）. Floating treatment wetlands（FTWs） showed comparable removal efficiencies for BOD（70.7%）,NH4-N（63.6%）, and TP（44.8%） to free water surface（FWS） CW systems.展开更多
文摘Unplanned urban population growth in developing countries such as Sri Lanka exert pressures on the sectors of water supply, sewage disposal, waste management, and surface drainage in the cities as well as their surrounding areas. The Mid-canal is considered the most polluted surface water body in the Kandy district of Sri Lanka and contributes significantly to pollution of the Mahaweli River. Health problems in the nearby population may well be associated with environmental degradation and related to deteriorated water quality. The overall objectives of this study were to identify the socio-economic status of the community settled along the Meda Ela banks, and to examine the current water quality status of the Meda Ela and possible impacts of the nearby residents on water quality. Additionally, we propose remedial measures concerning wastewater and solid waste disposal to improve environmental conditions in this area.
文摘Constructed wetlands（CWs） have been successfully used for treating various wastewaters for decades and have been identified as a sustainable wastewater management option worldwide.However,the application of CW for wastewater treatment in frigid climate presents special challenges.Wetland treatment of wastewater relies largely on biological processes,and reliable treatment is often a function of climate conditions.To date,the rate of adoption of wetland technology for wastewater treatment in cold regions has been slow and there are relatively few published reports on CW applications in cold climate.This paper therefore highlights the practice and applications of treatment wetlands in cold climate.A comprehensive review of the effectiveness of contaminant removal in different wetland systems including：（1） free water surface（FWS） CWs;（2） subsurface flow（SSF） CWs;and（3） hybrid wetland systems,is presented.The emphasis of this review is also placed on the influence of cold weather conditions on the removal efficacies of different contaminants.The strategies of wetland design and operation for performance intensification,such as the presence of plant,operational mode,effluent recirculation,artificial aeration and in-series design,which are crucial to achieve the sustainable treatment performance in cold climate,are also discussed.This study is conducive to further research for the understanding of CW design and treatment performance in cold climate.
文摘Constructed wetlands（CWs） have been successfully used for treating various wastewaters for decades and have been identified as a sustainable wastewater management option for developing countries. With the goal of promoting sustainable engineered systems that support human well-being but are also compatible with sustaining natural（environmental）systems, the application of CWs has become more relevant. Such application is especially significant for developing countries with tropical climates, which are very conducive to higher biological activity and productivity, resulting in higher treatment efficiencies compared to those in temperate climates. This paper therefore highlights the practice,applications, and research of treatment wetlands under tropical and subtropical conditions since 2000. In the present review, removal of biochemical oxygen demand（BOD） and total suspended solid（TSS） was shown to be very efficient and consistent across all types of treatment wetlands. Hybrid systems appeared more efficient in the removal of total suspended solid（TSS）（91.3%）, chemical oxygen demand（COD）（84.3%）, and nitrogen（i.e.,80.7% for ammonium（NH）4-N, 80.8% for nitrate（NO）3-N, and 75.4% for total nitrogen（TN））as compared to other wetland systems. Vertical subsurface flow（VSSF） CWs removed TSS（84.9%）, BOD（87.6%）, and nitrogen（i.e., 66.2% for NH4-N, 73.3% for NO3-N, and 53.3% for TN）more efficiently than horizontal subsurface flow（HSSF） CWs, while HSSF CWs（69.8%）showed better total phosphorus（TP） removal compared to VSSF CWs（60.1%）. Floating treatment wetlands（FTWs） showed comparable removal efficiencies for BOD（70.7%）,NH4-N（63.6%）, and TP（44.8%） to free water surface（FWS） CW systems.
