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 Chemical Treatment Facility $2.5 million ~ construction cost Minimal supervision No chemical additions required Needs to be filtered every 10 yrs • ~ $100,000.00 $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.