POTENTIAL OF DIFFERENT AQUATIC MACROPHYTES TOWARDS PHOSPHATE REMOVAL IN A CONSTRUCTED WETLAND

Abstract

Growth of phytoplankton in a water body is limited by the concentration of nutrients (Phosphate and Nitrogen) in that water body. Excessive growth of algae will leads to serious issues like eutrophication. Constructed Wetlands (CW) are an effective technology which is widely been used to remove nutrients from waste water. The present study had been undertaken in three wetlands that were constructed in the campus of Delhi Technological University with three different type of vegetation in it, to obtain the potential of plant to remove phosphate from waste water. Study was started in the month of June of 2018 and continued till March of 2019. The variation in the percentage removal with ambient temperature was monitored. Percentage removal of available phosphate (AP), and total phosphate (TP) in C. indica, and P. australis based cell was varied from 78 to % 25, and 71 to 31%, and 96 to 33% and 58 to 25%, respectively. AP removal in I. indica based cell was varied from 54 to 20%. Percentage removal of ammonia was also been monitored in all three wetland cells and it was varied from 91 to 65%, 94 to 81%, and 97 to 70%, for C.indica, I. indica and P. australis, respectively. Bioaccumulation in plants (for all three plants), trend of nutrient translocation in different part of plant (for C. indica) with season, and role of substrate in wetlands were also performed in this study. It was observed that stem allocate higher amount of phosphate than leaves and flower in C. indica, but relative accumulation of phosphate was observed higher in flower. Accumulation of phosphate by I. indica was found minimum due to low growth of the plant at available temperature. From the harvested tissue of C. indica it was observed that during growth period nutrient translocation is generally from bottom to top i.e. from roots to flower but in fall (autumn and winter) reverse translocation occur i.e. from flower to root. In the sediments of CW1 (C. indica) presence of non-apatite phosphate was found higher than apatite phosphate, which indicate stable form of phosphate. All three plants were found efficient to remove nutrient from waste water, although I. indica was found lesser adaptive to natural shocks than C. indica and P. australis.