Characteristics

Vegetation
Primarily reeds, which have extensive root systems.

Substrate
Usually gravel, sand, or soil that supports plant growth and provides habitat for microorganisms. Water Flow: Water is introduced at one end of the bed and flows through it, either horizontally or vertically, allowing time for treatment.

Filtration
Physical trapping of particles and sediments by the reeds and substrate.

Microorganisms
Microorganisms on the roots and substrate break down organic matter and pollutants.

Nutrient removal
Plants absorb nutrients like nitrogen and phosphorus, preventing eutrophication of downstream water bodies.
Pollutant Degradation: Breakdown of harmful chemicals and heavy metals through microbial activity and plant uptake.

Horizontal flow
Water flows horizontally through the bed. This type is effective for secondary and tertiary treatment.

Vertical flow
Water is introduced at the surface and flows vertically through the substrate. This type offers higher oxygenation and is suitable for primary treatment.