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

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.

Heat Transfer Characteristics and Pressure Drop in a Horizontal Circulating Fluidized Bed Evaporator

A vapor-liquid-solid horizontal circulating fluidized bed evaporation setup was constructed to study the thermal-exchange properties and pressure change.The influences of the operating variables,including the amount of added particles,heat flux,and circulating flow velocity,were systematically inspected using resistance temperature detectors and pressure sensors.The results showed that the heat transfer eff ect was improved with the increase in the amount of added particles,circulating flow velocity,and particle diameter,but decreased with increasing heat flux.The pressure drop fluctuated with the increase in operating parameters,except circulating flow velocity.The enhancing factor reached up to 71.5%.The enhancing fac-tor initially increased and then decreased with the increase in the amount of added particles and circulating flow velocity,fluctuated with increasing particle diameter,and decreased with increasing heat flux.Phase diagrams showing the variation ranges of the operation variables for the enhancing factor were constructed.