PHOSPHATE REMOVAL FROM WASTEWATER BY CANNA LILY

Abstract

A wetland is an area of land whose soil is saturated with moisture either permanently or seasonally, such that it takes on the characteristics of a distinct ecosystem. The capacity for wastewater purification by both natural and artificial wetlands is well documented. Wetlands remove pollutants through a complex variety of biological, physical, and chemical processes. There are many advantages of using constructed wetland over conventional system. The major problem in conventional system is the disposal of secondary pollutants (like Sludge) where as in wetland there is no such problem. As the application of constructed wetland (CW) as an advanced treatment, the usual aim is to remove nutrients (phosphorus & nitrogen compounds) which are detrimental to the balance of more sensitive receiving media where it may result in euthrophication. Wetlands are cheaper to construct than any other conventional treatment option. Operation and maintenance cost (energy and supplies) are lower in the case of CW since it is a natural process and it does not require continuous monitoring. Wetland treatment system use different water tolerant plant species. The basic types of constructed wetland treatment systems according to flow type include surface flow (SF) wetlands and subsurface flow (SSF) wetlands. There are three broad categories of wetland vegetation; 1) Emergent Aquatic Macrophytes ( like- Typha,Canna lily), 2) Floating-leaved aquatic macrophytes (i.e. Water hyacinth, Duckweed), 3) Submerged aquatic macrophytes. Most of the research on constructed wetlands has been conducted in European countries. As a result, the plants most studied for treatment purposes are those which can survive in cold conditions. However, there is little information about the efficacy of ornamental plants for use in treatment wetlands. The fact that these ornamental plants cannot survive the cold winters in northern countries may be one reason why they have had limited use in constructed wetlands. The use of ornamental plants in treatment wetlands has been explored in this study. Keeping this fact in mind the present study will mainly focused on phosphorus removal efficiency of Canna lily which has shown a high promise towards the removal of organic matter and nutrients. Another important objective of this study is to get an idea of various fractions of phosphate in wastewater, plant, and sediments. I