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
Recycling human urine for farming was assessed in a peri-urban Kyanja parish, Kampala district, and in a rural Migyera parish, Nakasongola district, to demonstrate its potential and develop local use guidelines. Test ...Recycling human urine for farming was assessed in a peri-urban Kyanja parish, Kampala district, and in a rural Migyera parish, Nakasongola district, to demonstrate its potential and develop local use guidelines. Test crops were maize, Nakati （Solanum aethiopicum）, kale, spinach, cabbage, tomatoes, egg plants. Urine-water mixtures （0, 10%, 20%, 30% urine） were applied weekly or bi-weekly. At Kyanja, 30% urine weekly gave the highest maize yields. Within 2 months, 10% urine weekly increased Nakati yield from 5,444 to 24,667 kg ha^-1. 20% Urine weekly increased kale yield （7,556 to 16,111 kg ha^-1） and spinach （4,222 to 19,022 kg ha^-1）. At Migyera, 10% urine weekly increased cabbage yield （4,975 to 16,113 kg ha^-1） but 30% urine weekly decreased cabbage head-weight by 36%. Weekly applied urine produced heavier cabbage heads than bi-weekly （548 g vs. 427 g, P 〈 0.05）. LeafN was higher for weekly than bi-weekly applied urine （3.3% vs. 3.0%）, implying more protein in the former than the latter. From this study, the following guidelines are proposed： Kyanja area, maize： apply 30% urine weekly for 8-weeks; Nakati： apply 10% urine weekly for 8-weeks; Kale and spinach： apply 20% urine weekly; For Migyera area, cabbage and spinach： apply 10% urine weekly. Apply urine 15 cm around each plant starting 2-weeks after transplanting. So kale and spinach prolong urine application for continued harvesting.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Recycling human urine for farming was assessed in a peri-urban Kyanja parish, Kampala district, and in a rural Migyera parish, Nakasongola district, to demonstrate its potential and develop local use guidelines. Test crops were maize, Nakati （Solanum aethiopicum）, kale, spinach, cabbage, tomatoes, egg plants. Urine-water mixtures （0, 10%, 20%, 30% urine） were applied weekly or bi-weekly. At Kyanja, 30% urine weekly gave the highest maize yields. Within 2 months, 10% urine weekly increased Nakati yield from 5,444 to 24,667 kg ha^-1. 20% Urine weekly increased kale yield （7,556 to 16,111 kg ha^-1） and spinach （4,222 to 19,022 kg ha^-1）. At Migyera, 10% urine weekly increased cabbage yield （4,975 to 16,113 kg ha^-1） but 30% urine weekly decreased cabbage head-weight by 36%. Weekly applied urine produced heavier cabbage heads than bi-weekly （548 g vs. 427 g, P 〈 0.05）. LeafN was higher for weekly than bi-weekly applied urine （3.3% vs. 3.0%）, implying more protein in the former than the latter. From this study, the following guidelines are proposed： Kyanja area, maize： apply 30% urine weekly for 8-weeks; Nakati： apply 10% urine weekly for 8-weeks; Kale and spinach： apply 20% urine weekly; For Migyera area, cabbage and spinach： apply 10% urine weekly. Apply urine 15 cm around each plant starting 2-weeks after transplanting. So kale and spinach prolong urine application for continued harvesting.
