Extensive Systems

Advantages

Disadvantages

Natural Lagoons

Low operational cost and little maintenance. Suitable for high pollutant loads. Good reduction of pathogens and organic matter.

Requires a large area. Sensitive to seasonal and climatic variations.

Horizontal flow constructed wetlands

Effective in treating BOD5, COD, nitrates, phosphates. Habitat for biodiversity. Low operational and maintenance costs.

Requires significant area. Less effective for high coliform loads. Sensitive to seasonal variations.

Vertical flow constructed wetlands

Effective in treating organic pollutants and nutrients. Low maintenance. Aesthetically pleasing.

Requires certain area. May require pretreatment for very high loads.

Infiltration Wells

Good for BOD5 reduction and solids filtration. Recharges groundwater.

Less effective for nutrients and pathogens. Risk of groundwater contamination.

Biological rotating contactors

Effective for reducing BOD5 and suspended solids. Compact footprint.

Requires mechanical equipment. Less effective for nutrient treatment.