Does a constructed wetland smell?

A constructed wetland does not smell. Just like with other types of wastewater treatment plants and sewer structures, there is no direct odor detectable as long as these facilities are properly designed and built. This is particularly important for sewer manholes and septic tanks, where anaerobic processes take place without access to air, generating the most odor. In a constructed wetland, wastewater flows beneath a gravel filter, effectively eliminating odor this way. Odor tends to occur from low pressure in the sewer system and septic tank rather than from the constructed wetland itself, which smells more like soil. Even with the French reed bed system, where wastewater is discharged directly onto the surface of the filter bed, no odor is smelled in the vicinity thanks to the optimal design and plants covering the entire filter bed.