Self-sustained semi-pilot scale Hybrid Eco-Electrogenic Engineered System for the wastewater treatment and bioenergy generation

Abstract

Eutrophication in water bodies is a pervasive water quality issue that should be remediated to restore and recover natural resources. The systematic arrangement of aquatic macrophytes in the water bodies through ecological engineering principles will treat wastewater and rejuvenate the ecosystem. In this context, a novel semi-pilot scale Hybrid Eco-Electrogenic Engineered System (HEEES) was operated using aquatic macrophytes and a bioelectrogenic system to treat domestic wastewater and generate bioenergy. Three similar tanks were used with different functionally diverse biota, viz., floating macrophytes (water hyacinth) in tank A, submerged plants (water thymes) in tank B, and emergent plants (water lettuce) in tank C. Four different experimental setups (ES) were performed by placing specific parameters such as electrodes, aerators, and activated carbon viz., ES1 (plants), ES2 (Plants + Activated Carbon), ES3 (Plants + Activated Carbon + Aerators), and ES4 (Plants + Activated Carbon + Aerators + Electrodes). The results infer that tank A with water hyacinth showed maximum COD removal efficiency of 76.90 % (ES1), 77.24 % (ES2), 80.01 % (ES3), and 81.67 % (ES4), respectively. Maximum power and current density of 24.104 mW/m2 and 23.844 mA/m2 were attained, inferring that the ES4 condition showed the maximum pollutant removal efficiency and bioenergy generation. It is attained due to specific parameters in the system that increases the electrogenic activity by electrodes, adsorbing the property of activated carbon and increasing the oxygen concentration by aeration, enhancing effective treatment and bioenergy generation in the single-chambered hybrid system. The semi-pilot scale HEEES is a self-sustained system that mimics the natural cleansing function of aquatic bio-networks.