Eco-Electrogenic Engineered Flow through Wetland System for Tertiary Treatment of Acidogenic Effluents from Biohydrogen Production

Abstract

Ecological intervention is used for a diverse range of applications to provide sustainable solutions toward restoring natural capital. Eco-electrogenic engineered wetland systems (EEWSs), coupled with a microbial fuel cell (MFC), were designed and operated to utilize the natural ecological abilities by way of mimicking nutrient cycles to obtain the requisite treatment. An EEWS, designed with floating, emergent, and submerged aquatic macrophytes integrated with an electrode assembly, was studied for the treatment of fermented wastewater (generated from biohydrogen production using food waste). The experiment was carried out with 250 and 500 mg/L of organic carbon load, which accounted for combined chemical oxygen demand (COD) removal efficiencies of 87% and 85% and volatile fatty acid (VFA) removal efficiencies of 87% and 80%, respectively. The maximum in situ potential of 1.5 and 1.9 V at the current densities of 17 and 18 mA was recorded, respectively, at 250 and 500 mg/L. The hybrid system showed high efficiency in removing fermented acid-rich effluents and can, therefore, be utilized as a promising polishing/final treatment unit with sustainable footprints.