Estimation of evapotranspiration in constructed wetlands under diverse climatic conditions

Constructed wetlands as a form of phytoremediation have proven to be an effective wastewater treatment method. It is a simple, economical, and environmentally friendly method compared to conventional wastewater treatments. In addition to wastewater treatment, constructed wetlands have been used to study hydrometeorological parameters such as evaporation in the vicinity, evapotranspiration (ET), and wastewater loss at a constructed wetland pilot plant at the Uttarakhand Jal Nigam sewage treatment plant at Haridwar. The relation between standard pan evaporation (PE) and ET occurring at the surface of a wetland bed was established at the constructed wetland site. To make the process of measuring ET easier, the relation between PE and ET has been established by the equation y = 0.3904x + 0.0192. The percent loss of water through ET vis-a-vis PE during the summer, post-monsoon, and winter seasons has been estimated to be 21.6%, 6.47%, and 1.16%, respectively. The quantity of wastewater lost in the summer, post-monsoon, and winter seasons was 53.06 m(3), 13.87 m(3), and 2.79 m(3), respectively. The total annual wastewater loss through the pilot scale constructed wetlands was 69.72 m(3). The loss of wastewater per square meter of the planned area of constructed wetland in the temperate zone was estimated as 3.46 m(3) per m(2) of constructed wetland. ET through wetlands enhanced the circulation of water in the hydrological cycle; therefore, this treatment has been proven to be an environmentally friendly method of wastewater treatment.