logo of the Joan White howell Environmental Education Center

Clay Hill 
Constructed Wetland Wastewater Facility

Water is 

a renewable resource


At Clay Hill Memorial Forest we make every effort to demonstrate novel, new or alternative technologies in our buildings and exhibits.  We are  located several miles from the nearest municipal sewer line.  Most of Clay Hill's neighbors treat domestic wastewater using septic tank drainage field systems.  Such systems release effluent below the surface of the ground, and this can result in contamination of groundwater.  Subsurface drainage fields, although the most commonly-used household system, are often not the most environmentally sound method for treating wastewater.  We typically host thousands of school children each year and expect the number of people visiting Clay Hill Memorial Forest and the Joan White Howell Environmental Education Center will continue to grow.  We needed an environmentally sound way to treat wastewater and found it in a constructed wetland.

We clean our "wastewater" with an above ground constructed wetland using natural processes.  Nutrients are removed from the water by plants such as cattails, rushes and irises as the water passes slowly thorough a series of rubber-lined, gravel-filled beds.  These plants along with bacteria and other microscopic organisms remove the nutrients from the water and utilize them for their own growth.   The water travels very slowly through this system but eventually reaches a sump.  From here it is pumped into our greenhouse where we have three tanks with tropical floating aquatic plants such as water hyacinth and African water lettuce.   These plants remove any remaining nutrients and remain active in winter months when the cattails are dormant.  The finished water is pumped from the greenhouse into a large aquarium in the Joan White Howell Environmental Education Center where children learn that water is a recyclable resource.  Overflow from the aquarium is returned to the wetland system to be cleaned and used again.   No water is ever released below the surface of the ground.  Children who visit Clay Hill learn that "wastewater" can be recycled to the extent that it is pure enough to supply water to fish tanks or water for human consumption.  Water is a recyclable resource!


Published 20 January 2005         Last modified  17 August 2012      Clay Hill Memorial Forest

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