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
Arid zones, which cover approximately 40 percent of the earth’s land surface, support complicated and widely varied ecological systems. As such, arid zones are an important composition of the global terrestrial ecosy...Arid zones, which cover approximately 40 percent of the earth’s land surface, support complicated and widely varied ecological systems. As such, arid zones are an important composition of the global terrestrial ecosystem, and water is the key and abiotic lim-ited factor in ecosystem-driven processes in these areas. Ecohydrology is a new cross discipline that provides, in an objective and comprehensive manner, novel ideas and approaches to the evaluation of the interaction and feedback mechanisms involved in the soil–vegetation systems in arid zones. In addition, ecohydrology provides a theoretical basis of ecological restoration that is cen-tered on vegetation construction. In this paper, long-term monitoring and local observations in the transitional belt between a de-sertified steppe and a steppified desert at the Shapotou Desert Research and Experiment Station, Tengger Desert, in northern China, were evaluated. The primary achievements and related research progress regarding ecohydrology in arid zones were analyzed and summarized, as a keystone, and the response of soil ecohydrological processes to the changes in the species composition, structure, and function of sandland vegetation was discussed. Meanwhile, the long-term ecological effects and mechanism of regulation of vegetation on soil habitat and on water-cycling were considered. As a vital participant in the ecohydrological processes of soil–vegetation systems, the studies on biological soil crusts was also summarized, and related theoretical models of restoration based on the water balance was reviewed.展开更多
Ecosystems engineering is specially designed for study and management of ecosystems. Its theory and method-ology are mainly derivcd from systems ecology and systems engineering An ecosystem is a biologically functiona...Ecosystems engineering is specially designed for study and management of ecosystems. Its theory and method-ology are mainly derivcd from systems ecology and systems engineering An ecosystem is a biologically functional entityconsisting of organisms, environmental factors and their interactional mechanisms which are naturally or artificially ar-ranged with their approytiate functions in the system and also subordinaled to the dynamics of the whole ecosystem If an ecosystem is broken or disintegrated into independent or isolated parts. its structural and functional entity will be greatly modified or even completely destroyed Yet without participation of organisms including human beings, a system is not anecosystem. Within an ecosystem, all life, production and social activities are directly or indirectly rclated to the energy flowand material exchange In fact. energy is a driving force for material exchange and material is the carrier of energy flowTherefore, an ecosystem can be logically recognized as an energy system Its components. structure, function. production,quality and benefits can be expressed, calculated and modelled in terms of energy. Ecoboundary theory is also used in thediscussion of pathways of energy flow. As being applied to agrolioresty management, envirommental conservation and com-munity social service which are all complicated ecosystems, ecosystem engineering requires a series of programming meas-ures such as investigation, decision-making, planning, simulating, design, establishment, management, evaluation and reno-vation so that an appropriate ecosystem with stable structure, ellective function and high productivity can be established forits expected economic, ecological and social benefits.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.
基金supported by the National Natural Scientific Foundation of China (40825001)
文摘Arid zones, which cover approximately 40 percent of the earth’s land surface, support complicated and widely varied ecological systems. As such, arid zones are an important composition of the global terrestrial ecosystem, and water is the key and abiotic lim-ited factor in ecosystem-driven processes in these areas. Ecohydrology is a new cross discipline that provides, in an objective and comprehensive manner, novel ideas and approaches to the evaluation of the interaction and feedback mechanisms involved in the soil–vegetation systems in arid zones. In addition, ecohydrology provides a theoretical basis of ecological restoration that is cen-tered on vegetation construction. In this paper, long-term monitoring and local observations in the transitional belt between a de-sertified steppe and a steppified desert at the Shapotou Desert Research and Experiment Station, Tengger Desert, in northern China, were evaluated. The primary achievements and related research progress regarding ecohydrology in arid zones were analyzed and summarized, as a keystone, and the response of soil ecohydrological processes to the changes in the species composition, structure, and function of sandland vegetation was discussed. Meanwhile, the long-term ecological effects and mechanism of regulation of vegetation on soil habitat and on water-cycling were considered. As a vital participant in the ecohydrological processes of soil–vegetation systems, the studies on biological soil crusts was also summarized, and related theoretical models of restoration based on the water balance was reviewed.
文摘Ecosystems engineering is specially designed for study and management of ecosystems. Its theory and method-ology are mainly derivcd from systems ecology and systems engineering An ecosystem is a biologically functional entityconsisting of organisms, environmental factors and their interactional mechanisms which are naturally or artificially ar-ranged with their approytiate functions in the system and also subordinaled to the dynamics of the whole ecosystem If an ecosystem is broken or disintegrated into independent or isolated parts. its structural and functional entity will be greatly modified or even completely destroyed Yet without participation of organisms including human beings, a system is not anecosystem. Within an ecosystem, all life, production and social activities are directly or indirectly rclated to the energy flowand material exchange In fact. energy is a driving force for material exchange and material is the carrier of energy flowTherefore, an ecosystem can be logically recognized as an energy system Its components. structure, function. production,quality and benefits can be expressed, calculated and modelled in terms of energy. Ecoboundary theory is also used in thediscussion of pathways of energy flow. As being applied to agrolioresty management, envirommental conservation and com-munity social service which are all complicated ecosystems, ecosystem engineering requires a series of programming meas-ures such as investigation, decision-making, planning, simulating, design, establishment, management, evaluation and reno-vation so that an appropriate ecosystem with stable structure, ellective function and high productivity can be established forits expected economic, ecological and social benefits.
