In Saint-Louis, Senegal, a constructed wetland with horizontal flow reed beds (FHa and FHb) has demonstrated significant efficacy in treating municipal wastewater. Analyzing various treatment stages, the system showed...In Saint-Louis, Senegal, a constructed wetland with horizontal flow reed beds (FHa and FHb) has demonstrated significant efficacy in treating municipal wastewater. Analyzing various treatment stages, the system showed only a slight temperature variation, from an influent average of 26.3°C to an effluent of 24.7°C. Electrical conductivity decreased from 1331 mS/cm to 974.5 mS/cm post-primary treatment, with suspended solids (SS) dramatically reduced from 718.9 mg/L to 5.7 mg/L in the final effluent. Biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) saw a notable decrease, from initial levels of 655.6 mg/L and 1240 mg/L to 2.3 mg/L and 71.3 mg/L, respectively. Nitrogenous compounds (N-TN) and phosphates () also decreased significantly, indicating the system’s nutrient removal capacity. Microbiological analysis revealed a reduction in fecal coliforms from 7.5 Ulog/100ml to 1.8 Ulog/100ml and a complete elimination of helminth eggs. The presence of Phragmites and Typha was instrumental in enhancing these reductions. The system’s compliance with the Senegalese standards for disposal into natural environments, WHO recommendations for unrestricted water reuse in irrigation, and the European legislation for water reuse was established. The effluent quality met the stringent criteria for various classes of agricultural reuse, illustrating the system’s potential for sustainable water management. This wetland model presents a robust solution for water-stressed regions, ensuring environmental protection while supporting agricultural needs. The study calls for ongoing research to further refine the system for optimal, reliable wastewater treatment and water resource sustainability.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
The use of constructed wetlands to treat municipal wastewater reduces energy consumption and therefore economic costs,as well as reduces environmental pollution.The purpose of this study was to compare the purificatio...The use of constructed wetlands to treat municipal wastewater reduces energy consumption and therefore economic costs,as well as reduces environmental pollution.The purpose of this study was to compare the purification capacity of domestic wastewater using two species of plants sown in subsurface constructed wetlands with vertical flow built on a small scale that received municipal wastewater with primary treatment.The species used were Phragmites Australis and Cyperus Papyrus.For this purpose,a constant flow of 0.6 m3 day-1 was fed from the primary lagoon to each of the two wetlands built on a pilot scale with continuous flow.Each unit was filled with granite gravel in the lower part and with silicic sand in the upper part of different granulometry,the porosity of the medium was 0.34,with a retention time of 1.12 days and a hydraulic load rate of 0.2 m day-1.To analyze the purification capacity of wastewater,physical,chemical and biological parameters were monitored during three months.Samples were taken at the entrance and exit in each experimental unit.The results obtained in the experimental tests for the two species of plants,indicated that the Cyperus Papyrus presented a greater capacity of pollutants removal as biochemical oxygen demand (80.69%),chemical oxygen demand (69.87%),ammoniacal nitrogen (69.69%),total phosphorus (50%),total coliforms (98.08%) and fecal coliforms (95.61%).In the case of Phragmites Australis retains more solids.The species with greater efficiency in the treatment of municipal wastewater for this study was Cyperus Papyrus.展开更多
文摘In Saint-Louis, Senegal, a constructed wetland with horizontal flow reed beds (FHa and FHb) has demonstrated significant efficacy in treating municipal wastewater. Analyzing various treatment stages, the system showed only a slight temperature variation, from an influent average of 26.3°C to an effluent of 24.7°C. Electrical conductivity decreased from 1331 mS/cm to 974.5 mS/cm post-primary treatment, with suspended solids (SS) dramatically reduced from 718.9 mg/L to 5.7 mg/L in the final effluent. Biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) saw a notable decrease, from initial levels of 655.6 mg/L and 1240 mg/L to 2.3 mg/L and 71.3 mg/L, respectively. Nitrogenous compounds (N-TN) and phosphates () also decreased significantly, indicating the system’s nutrient removal capacity. Microbiological analysis revealed a reduction in fecal coliforms from 7.5 Ulog/100ml to 1.8 Ulog/100ml and a complete elimination of helminth eggs. The presence of Phragmites and Typha was instrumental in enhancing these reductions. The system’s compliance with the Senegalese standards for disposal into natural environments, WHO recommendations for unrestricted water reuse in irrigation, and the European legislation for water reuse was established. The effluent quality met the stringent criteria for various classes of agricultural reuse, illustrating the system’s potential for sustainable water management. This wetland model presents a robust solution for water-stressed regions, ensuring environmental protection while supporting agricultural needs. The study calls for ongoing research to further refine the system for optimal, reliable wastewater treatment and water resource sustainability.
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The use of constructed wetlands to treat municipal wastewater reduces energy consumption and therefore economic costs,as well as reduces environmental pollution.The purpose of this study was to compare the purification capacity of domestic wastewater using two species of plants sown in subsurface constructed wetlands with vertical flow built on a small scale that received municipal wastewater with primary treatment.The species used were Phragmites Australis and Cyperus Papyrus.For this purpose,a constant flow of 0.6 m3 day-1 was fed from the primary lagoon to each of the two wetlands built on a pilot scale with continuous flow.Each unit was filled with granite gravel in the lower part and with silicic sand in the upper part of different granulometry,the porosity of the medium was 0.34,with a retention time of 1.12 days and a hydraulic load rate of 0.2 m day-1.To analyze the purification capacity of wastewater,physical,chemical and biological parameters were monitored during three months.Samples were taken at the entrance and exit in each experimental unit.The results obtained in the experimental tests for the two species of plants,indicated that the Cyperus Papyrus presented a greater capacity of pollutants removal as biochemical oxygen demand (80.69%),chemical oxygen demand (69.87%),ammoniacal nitrogen (69.69%),total phosphorus (50%),total coliforms (98.08%) and fecal coliforms (95.61%).In the case of Phragmites Australis retains more solids.The species with greater efficiency in the treatment of municipal wastewater for this study was Cyperus Papyrus.
