constructed wetlands
Constructed wetlands are inherently engineered to be mechanically simple, yet ecologically complex. The system is a passive, lined reactor following primary treatment in an anaerobic digester or septic tank (for smaller systems). The wetlands provide high-quality secondary treatment that does not require external energy for treatment (thus little to no maintenance and low operating costs) while also being an aesthetic addition to the landscape.
Benefits of Wetland Technologies for Wastewater Treatment:
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Non-proprietary (constructed wetlands): Allows for capacity building and technology transfer
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Stimulates the local economy by using most if not all locally sourced materials.
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Treatment does not require external energy or chemicals to operate (Considerably lower O&M costs vs. conventional packaged treatment plants)
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Wetlands polish excess nutrients, preventing pollution downstream
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Educational value and opportunities
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Provide LEED credits
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Aesthetically pleasing
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Convert Wastes to Resources. Produce valuable byproducts such as flowers, fodder, and water ready for reuse.
In subsurface flow (SSF) wetlands all water flows below the surface and the plant roots and gravel provide substrates for microorganism attachment. The two media provide different habitats that allow for both aerobic and anoxic bacteria to reside in the same ecosystem which allows for an efficient breakdown of a range of pollutants. In doing so it converts waste into resources via the complex food web. Another significant advantage to a SSF wetland is lack of odor since all the water flows beneath the surface of the wetland. Furthermore, the wetland treatment system can showcase native and local tropical plants that promote the local culture, regional biodiversity and can provide opportunities for commercial harvest. The wetland technology will naturally provide the Hawaii Department of Health R-3 quality reuse water without the need for external energy or chemicals and can meet R-2 and R-1 with disinfection. In addition, the systems are excellent in removing nutrients such as ammonia and nitrates, which protects fragile ecosystems and groundwater supplies where disposal/water reuse occurs.