Wetlands phytoremediation

Metal removal in SSFCWs has been recently focused on metal elimination from synthetic water and different wastewaters,66-86 on the evaluation of the effects of season, temperature, plant species, and chemical oxygen demand (COD) loading on metals removal,87 and on the accumulation of metals in wetland plant species and sediments.88-89 Recent reviews on heavy metal phytoremediation wetlands are also available.48... 

Phytofiltration, a specific strategy of phytoremediation, is the use of plants to remove contaminants from water and aqueous waste streams. Three different systems (Figure 10.1) can be considered within this strategy (a) rhizofiltration (the use of hydroponically cultivated plant roots),31112 (b) constructed wetlands (CWs) and lagoons, and (c) bioadsorbents-based systems.1... 

Zhang, X., Liu, P., Yang, Y., and Chen, W., Phytoremediation of urban wastewater by model wetlands with ornamental hydrophytes, Journal of Environmental Sciences, 19, 902-909, 2007. 

Rai, P.K., Heavy metal pollution in aquatic ecosystems and its phytoremediation using wetland plants An ecosustainable approach, International Journal of Phytoremediation, 10, 133-160, 2008a. 

Gruber, H., Wiessner, A., Kuschk, P., Kaestner, M., and Appenroth, K.J., Physiological responses of Juncus effusus (rush) to chromium and relevance for wastewater treatment in constructed wetlands, International Journal of Phytoremediation, 10 (2), 79-90, 2008. 

Weis, J.S. and Weis, P., Metal uptake, transport and release by wetlands plants implication for phytoremediation and restoration, Environment International, 30 (5), 739-753, 2004. 

Liao, S.W. and Chang, N.L., Heavy metal phytoremediation by water hyacinth at constructed wetlands in Taiwan, Journal of Aquatic Plant Management, 42, 60-68, 2004. 

Azaizeh, H., Salhani, N., Sebesvari, Z., Shardendu, S., and Emons, H., Phytoremediation of selenium using subsurface-flow constructed wetland, International Journal of Phytoremediation, 8 (3), 187-198, 2006. 

If the plants do not take up the dissolved contaminant, the plume that emerges will be concentrated (i.e., the mass of contaminant in the plume will be the same, but the concentration remaining will actually be greater due to the reduction in water volume caused by the vegetation). This is a potential concern for phytoremediation of groundwater plumes or in created wetlands, where a relatively hydrophilic contaminant can be concentrated on the downstream side of the phytotechnology system. 

From the 323 MTBE treatment profiles, eight projects were identified where MTBE was treated using phytoremediation. These projects used various approaches, including hybrid poplar trees, Monterey pine, oak, eucalyptus, and engineered wetlands. 

Home A.I, Phytoremediation by constructed wetlands. In Phytoremediation of Contaminated Soil and Water, N. Terry, G. Banuelos, eds. Boca Raton, FL Lewis... 

T0016 Advanced Separation Technologies, Inc., ISEP Continuous Contactor T0045 Applied Research Associates, Inc., Bioremediation of Perchlorate T0158 CH2M Hill, Phytoremediation-based Systems T0178 Constructed Wetlands—General... 

Indeed, all phytoremediation processes or technologies are not exclusive and may be used simultaneously. For example, a constructed treatment wetland may involve all the phytoremediation processes for the cleanup of wastewaters contaminated with both metals and organic compounds. 

Given the abundance of Fe in soils, the variety of mineral forms that it may take, and the complex interactions of those mineral forms with other metals, Fe minerals often play an essential role in the overall control of metal interactions in the soil. This is especially true in the rhizosphere, where as discussed above, microbially mediated cycling of Fe between oxidized and reduced forms can be rapid. Wetland plants can increase metal sequestration by driving the formation of Fe plaque, particularly in tidal wetland soils, where burial is rapid. The binding of metals to Fe plaque in the rhizosphere is one reason that wetland plants have been investigated for the phytoremediation of metal-contamuiated sites (Weis and... 

Scientists are now exploring the use of plants and their associated microorganisms for remediation, which is called phytoremediation. This is a low cost process that is proving effective for a wide variety of contaminants, including petroleum hydrocarbons. It can be used in combination with other remediation technologies and may prove useful in the future for treating oiled soils or wetlands. It takes several years to remediate a site and cleanup is limited to the depth of the soil within reach of the plant s roots. 

Engineered reed-bed and constructed wetland systems for removal of heavy metals from wastewater using phytoremediation are in use in some developed Asian countries. The root system of the hyper-accumulator plant penetrates a permeable rock bed. The wastewater is introduced into one end of the bed and flows through the permeable rock layer. The rock layer should be inert to heavy metals binding so that it does not unwittingly serve as a sink for heavy metals. These metals are sequestered by the root system and translocated to the shoots. Periodically, the metal-containing shoots are harvested. The biomass can be burned off or composted to yield a low volume of metal-rich ash. 

Williams JB. (2002). Phytoremediation in wetland ecosystems Progress, problems and potential. Critical Reviews in Plant Sciences 21(6) 607-635. 

The following case studies give examples of approaches used to estimate plant uptake for phytoremediation and risk assessment purposes. The first uses a minimal number of inputs to estimate the amount of a highly water soluble compound removed by cattails growing in a contaminated wetland. The second example is a brief summary of a mechanistic model for estimating the concentration of neutral organic chemicals in apples growing in contaminated soil. 

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