by Jenni Swenson, SWC, UofM
Engineered system - Utilize natural processes to treat wastewater. These systems will replace the need for individual septic tank drainfields in developments that are not connected to city sewer.
To aid in construction these systems are often built in a an existing wetland, basin or channel. Some kind of subsurface barrier is used to limit seepage into subsoils or groundwater if the soils are permeable.
Water flows below a media of sand, gravel, and rock Grasses and trees are common plant materials that can be used and the amount of land is minimal
In some cases the Subsurface flow units can be constructed so that boxes are used to treat the sewage.
Water flows over soil media
Water <18” deep with sedges, reeds, rushes the major plant materials.
This is a land intensive system
Similar to FWS except the water >18” Typical plants include water hyacinth, duckweed, & pennywort. Fish can also be used in this system to aid in nutrient absorption.
Constructed wetland information provided by Jenni Swenson
Back to Soil Water Chapter 3
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