MICROBIAL POPULATION IN MICROCOSMS AND NUTRIENT REMOVAL FROM CONSTRUCTED WETLANDS

Abstract

Water scarcity is an issue of global concern due to discharge of untreated effluent and many other reasons. For the treatment of wastewater, a cost effective and ecologically beneficial treatment system should be used like constructed wetlands especially in developing countries. Constructed wetlands are engineered system in which plants are grown which remove pollutants naturally. The aim of this study was to analyze the type of microbial population of wastewater present in different layers of constructed wetlands and to observe plant growth and nutrient removal through these plants. Water quality parameters were analyzed by using standard methods. Bacterial isolates were isolated and identified through sequencing analysis. Plant growth was observed and nutrient removal was calculated. Maximum removal of TSS and COD was observed at high temperature as removal efficiency for COD was 52 in pilot scale and 71.9% in lab scale while in surface and benthic layers 71% and 74 % removal was noted respectively. TSS removal in pilot and lab scale was 72.8% and 79.4% respectively. At different layers almost same amount of removal was observed. Fourteen isolates were retrieved out of which 10 isolates belongs to proteobacteria group while remaining 4 belongs to firmicutes. Observed growth rate of Centella asiatica and Pistia stratiotes was higher in summer season in higher temperatures. Similarly, high nutrient removal observed in summer. Orthophosphate removal observed was 27 and 43% in pilot and lab scale respectively. Removal of nitrates and ammonia was high in lab scale i.e. 84.5 and 79.5% respectively.