A review on nitrogen and organics removal mechanisms in subsurface flow constructed wetlands: Dependency on environmental parameters, operating conditions and supporting media

The physiological and biochemical mechanism of nitrate-nitrogen removal by water hyacinth from agriculture eutrophic wastewater

“…Therefore, researchers around the world are paying more attention to the ecological restoration of polluted water by using aquatic plant (Zhang et al, 2014;Vymazal, 2013;Saeed and Sun, 2012). Water hyacinth (Pontederiaceae, EichhorniaKunth), one of the floating plants, has developed root system underwater.…”

“…Water hyacinth can purify eutrophic water and special material contaminated water, such as polymer organic wastewater, heavy metal wastewater, landfill leachate, etc (Zimmels et al,2006;Schneider et al1995;Guittonny et al, 2014). Applying in rivers, lakes, aquatic plant pond, surface flow constructed wetland is the primary application form of water hyacinth (Zhang et al, 2014;Vymazal, 2013;Saeed and Sun, 2012). The results of the experiments demonstrate that water hyacinth can not only absorb N and P (Zimmels et al, 2006;Zhang et al, 2006), but also remove heavy metal (Cd, Cu, Ni and Pb, etc) (Lin, 2013), toxic substance such as As (Alvarado et al, 2008), radioactive substance such as 137 Cs and 60 Co (Saleh, 2012) and organic pollutants (Saeed and Sun, 2012)in waste water.…”

“…Applying in rivers, lakes, aquatic plant pond, surface flow constructed wetland is the primary application form of water hyacinth (Zhang et al, 2014;Vymazal, 2013;Saeed and Sun, 2012). The results of the experiments demonstrate that water hyacinth can not only absorb N and P (Zimmels et al, 2006;Zhang et al, 2006), but also remove heavy metal (Cd, Cu, Ni and Pb, etc) (Lin, 2013), toxic substance such as As (Alvarado et al, 2008), radioactive substance such as 137 Cs and 60 Co (Saleh, 2012) and organic pollutants (Saeed and Sun, 2012)in waste water. It is reported (Zhang and Wang, 2007)that water hyacinth purifying water quality includes following approach: 1) overspreading the surface of water body with leaves, as a result the algae die because photosynthesis is blocked; 2) creating a favorable growth condition for microorganism by temperature adjustment; 3) supplying microorganism of carbon source which was composed of leaves; 4) supplying attached carrier, filtering pollutant, absorbing nutrition (N, P, some heavy metals and organic matters) for microorganism by developed roots; 5) degrading pollutant by root attached microorganism; 6) redistributing intracorporal nutrient substance and adjusting its own shape to achieve the best reproduction rate (Xie et al, 2004).…”

Treatment of Lakeside Domestic Wastewater by an Artificial Horizontal Undercurrent Wetland

“…They have proven to be quite effective and efficient, both in terms of economic efficiency and environmental effectiveness, especially for treatment of wastewater in rural areas [19][20]. In order to test if this solution may also suit the demands for treating lakeside wastewater, a horizontal undercurrent artificial wetland was constructed in the town of Wu-Cheng, of Jiu-Jiang City.…”

A combined application of different engineering and biological techniques to remediate a heavily polluted river

“…However, these techniques have many disadvantages, such as being time-consuming, costly and requiring significant space (Zhu et al, 2011;Meyer, 2012;Saeed and Sun, 2012). Techniques using combined biotechnological and engineering methods to remediate heavily polluted rivers have been attracting increasing attention in the environmental protection field (Arini et al, 2012;Sheng et al, 2012).…”