TITLE:
Performance of a Horizontal Flow Constructed Reed Bed Filter for Municipal Wastewater Treatment: The Case Study of the Prototype Installed at Gaston Berger University, Saint-Louis, Senegal
AUTHORS:
Abdou Khafor Ndiaye, Falilou Coundoul, Abdoulaye Deme, Antonina Torrens Armengol, Abdoulaye Senghor
KEYWORDS:
Constructed Wetlands, Horizontal Flow Reed Beds, Wastewater Treatment, Phragmites and Typha Plants, Physicochemical Pollutant Removal, Microbiological Indicators, Fecal Coliforms and Helminth Eggs, Water Quality Improvement, Senegal Water Reuse Standards, Sustainable Water Management, Agricultural Irrigation Reuse, Nutrient Removal Efficiency, Environmental Engineering, Ecological Sanitation Systems
JOURNAL NAME:
Natural Resources,
Vol.15 No.1,
January
18,
2024
ABSTRACT: 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.