EFFICACY OF PHRAGMITES-BASED CONSTRUCTED WETLAND FOR THE REMOVAL OF PHOSPHATES FROM WASTEWATER

Abstract

In many cities, towns, villages and in other places of the world, wastewater from individual houses, small settlements, dwelling units and industries discharges their effluent into the nearby water body and thus indirectly into the environment with only poorly efficient primary treatment system or without any treatment at all which in return often poses a significant threat, danger and damage to the public and environmental health (Gardner et al., 1997). In order to limit the groundwater pollution, contamination and eutrophication of surface water bodies such as lakes, ponds and rivers, regulations for the discharge of treated wastewater have become more strict in recent years which makes nutrients such as phosphate and nitrate removal an increasingly common requirement for all small and decentralized wastewater treatment systems (Sasse, 1998; Wallace & Knight, 2006). In comparison to many conventional and modern wastewater treatment methods and technologies, treatments using the application of wetlands are low cost, relatively simple to operate and can be constructed out of local materials available near the proposed site. Wetlands are the land area that is wet during part or all of the year because of their location in the landscape. Wetlands are also called as swamps, marshes, bogs, fens or sloughs depending upon existing plant and water conditions and on geographic setting. Wetlands are frequently transitional between uplands terrestrial system and continuously or deeply flooded aquatic system. The only thing that differentiates wetlands from other land or water bodies is the presence of characteristic vegetation which is adapted to unique soil which consists of hydric soil and supports the aquatic plants. Wetlands hold seemingly magical properties that make them unique among major ecosystem groups on the earth. Thus, wetlands also play a number of roles in the environment in terms of its protection and diversity, which majorly includes water purification, flood control, and shoreline stability and they are most biologically diverse of all ecosystems, serving as home to a wide range of plant and animal life. Wetlands have an important role in the preservation of environmental quality due to their high capacity for retention and inactivation of harmful substances and for carbon sequestration (Reddy & DeLaune, 2008).