Characteristics of Wetlands

 Must have  Hydrophytes • Soils that are saturated, flooded or ponded long enough to develop anaerobic conditions.

 Hydrophilic plants • From Reeds List  Standing water for all or part of the year.

Two Kinds of Wetlands

 Naturally Occurring Wetland  Constructed Wetland

Naturally Occurring Wetland

Mangrove swamp on San Jose Island

Naturally Occurring Wetland

 Two categories  Coastal Wetland ~ 11 million hectares  Inland Wetland ~ 32 million hectares

Constructed Wetlands in the U.S

 Over 600 active projects across the United States  In Arizona ~ 26 on-site and constructed wetlands operating in the State ~ 24 waiting to be approved or under construction.

 1990 ~ 4 constructed Wetlands

Constructed Wetland

   Wildlife Habitat Integral Man-made system  Water, plants, microorganisms, soils, and air interact to improve water quality.

Water treatment facility  Filtration and water regeneration

Uses of Constructed Wetlands

 Water Treatment facility  Treat wastewater  Wildlife Refuge  Revival of species or introduction of new species  Restored Wetland  Under rehabilitation

Two Systems of Constructed Wetlands  Surface Flow System/ Free Water Wetland  Subsurface System

Advantages of Constructed Wetlands         Low Construction and Operating Cost Cheap alternative to wastewater filtration High level of wastewater treatment Efficient treatment of wastewater Reduces if not eliminates odors Able to handle variable wastewater loadings Reduced land area needed for application of wastewater Wildlife habitat

Construction & Operating Cost Constructed Wetlands vs. Chemical Treatment Facilities  Constructed Wetlands     $2.5 million ~ construction cost Minimal supervision No chemical additions required Needs to be filtered every 10 yrs • ~ $100,000.00

 Chemical Treatment Facility  $4.8 million ~ $8.8 million (construction cost) • Comparable size

High Level of Wastewater Treatment 

Figure 1 - Summary results of the percentage of pollutants removed from three (3) demonstrational constructed wetlands. NOTE: In the case of nitrate nitrogen on Site #1, very little was present in the inflow, so little could be removed.

 Kenneth D. Simeral Associate Professor The Ohio State University

Limitations  Continuous supply of water is needed.

 Affected by Seasonal Weather Conditions  Can be Destroyed by an overload of solids or ammonia levels  Can remove Nutrients that can be used by crops.