Role of Wetland Plants and Use of Ornamental Flowering Plants in Constructed Wetlands for Wastewater Treatment: A Review

Abstract

The vegetation in constructed wetlands (CWs) plays an important role in wastewater treatment. Popularly, the common emergent plants in CWs have been vegetation of natural wetlands. However, there are ornamental flowering plants that have some physiological characteristics similar to the plants of natural wetlands that can stimulate the removal of pollutants in wastewater treatments; such importance in CWs is described here. A literature survey of 87 CWs from 21 countries showed that the four most commonly used flowering ornamental vegetation genera were Canna, Iris, Heliconia and Zantedeschia. In terms of geographical location, Canna spp. is commonly found in Asia, Zantedeschia spp. is frequent in Mexico (a country in North America), Iris is most commonly used in Asia, Europe and North America, and species of the Heliconia genus are commonly used in Asia and parts of the Americas (Mexico, Central and South America). This review also compares the use of ornamental plants versus natural wetland plants and systems without plants for removing pollutants (organic matter, nitrogen, nitrogen and phosphorous compounds). The removal efficiency was similar between flowering ornamental and natural wetland plants. However, pollutant removal was better when using ornamental plants than in unplanted CWs. The use of ornamental flowering plants in CWs is an excellent option, and efforts should be made to increase the adoption of these system types and use them in domiciliary, rural and urban areas.

Wastewater Treatment by Constructed Wetland Eco-Technology: Influence of Mineral and Plastic Materials as Filter Media and Tropical Ornamental Plants

“…This last specie never produced flowers during the study. The better growth characteristics for Canna are derivative of nature of the species and easy adaptation to wetland conditions reported in other studies [22]. For H. coronarium, also called matandrea, white or ginger butterfly, depending on the region, reproduction is important because several of its components such as rhizomes or leaves have been reported to be beneficial against infections and joint pain, probably more time in CW conditions are necessary for flower production [23].…”

Can Constructed Wetlands be Wildlife Refuges? A Review of Their Potential Biodiversity Conservation Value

“…The purification function of CWs also inevitably leads to the clogging of filtration media and substrate pores [38,119]. In addition, the treatment efficacy of CWs is significantly influenced by the plant species used and environmental factors [120,121]. For example, using plants with high biomass and evapotranspiration rates, strong resistance to pollution stress and low temperatures, fast growth and colonization rates, can alleviate some of these disadvantages to some extent.…”

Effect of Ornamental Plants, Seasonality, and Filter Media Material in Fill-and-Drain Constructed Wetlands Treating Rural Community Wastewater

“…[8]. However, there are local ornamental plants (plants grown or maintained for its aesthetic features, like its color, fragrance, flower production, attractive pattern, or design, are called ornamental plants) that have not been tested for their ability to remove pollutants, even though ornamental plants represent an economic alternative for developing countries, where wastewater treatment represents a large expenditure of the municipal budget [9][10][11]. Another important feature in treatment wetlands' design is the filter media.…”