Design of floating wetland for treatment of municipal wastewater and environmental assessment using emergy technique
The magnitude of wastewater has been increased due to rapid increase in population and industrialization in Faisalabad, Pakistan. Wastewater is being discharged directly into fresh water bodies without proper treatment due to insufficient treatment facilities which give rise to health problems. Wastewater treatment by chemical and thermal techniques is costly because these techniques rely on the use of chemicals and electricity. This study was planned to replace the chemical and thermal
... es with a floating wetland system which is an environmental protective technique for wastewater treatment. First order plug flow kinetic model was applied to calculate the surface area of wetland. This study also incorporates calculation of the emergy associated with the production of treated wastewater. From the whole calculations, it was observed that the total emergy of floating wetland 3.24×10 17 sej/year is less as compared to conventional effluent treatment plant having emergy 5.71×10 17 sej/year. The analysis indicates that use of floating wetland system can reduce cost as well as pressure on the local environment by providing option to reuse the wastewater after treatment. Results indicate that cost-benefit ratio was 0.88 which shows saving 3.7×10 17 sej/year of surface water resources by using treated wastewater for agricultural production. Wastewater treatment by floating wetland system is environmental friendly, cost effective and energy efficient as compared to effluent treatment system. The study suggests that wetland system should be recommended for wastewater treatment in areas where large quantity of wastewater is generated from municipal sector.