Life cycle, techno-economic and dynamic simulation assessment of bioelectrochemical systems: A case of formic acid synthesis

Mobolaji Shemfe,Siddharth Gadkari,Eileen Yu,Shahid Rasul,Keith Scott,Ian M Head,Sai Gu,Jhuma Sadhukhan

doi:10.1016/j.biortech.2018.01.071

Mobolaji Shemfe, Siddharth Gadkari + Show 6 more

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https://doi.org/10.1016/j.biortech.2018.01.071

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Abstract

A novel framework, integrating dynamic simulation (DS), life cycle assessment (LCA) and techno-economic assessment (TEA) of a bioelectrochemical system (BES), has been developed to study for the first time wastewater treatment by removal of chemical oxygen demand (COD) by oxidation in anode and thereby harvesting electron and proton for carbon dioxide reduction reaction or reuse to produce products in cathode. Increases in initial COD and applied potential increase COD removal and production (in this case formic acid) rates. DS correlations are used in LCA and TEA for holistic performance analyses. The cost of production of HCOOH is €0.015–0.005 g−1 for its production rate of 0.094–0.26 kg yr−1 and a COD removal rate of 0.038–0.106 kg yr−1. The life cycle (LC) benefits by avoiding fossil-based formic acid production (93%) and electricity for wastewater treatment (12%) outweigh LC costs of operation and assemblage of BES (−5%), giving a net 61MJkg−1 HCOOH saving.

Highlights

Research interest in renewable fuels has intensified over the last two decades due to the finiteness of fossil fuels and concern about their environmental issues (IPCC, 2014)
Number of electrons transferred per mole of formic acid molar flux of substrate passing through the biofilm
This paper aims to meet this challenge by presenting the first ever integrated life cycle assessment (LCA), techno-economic assessment (TEA) and dynamic simulation (DS) framework to study the performance of bioelectrochemical system (BES) for simultaneous wastewater bioremediation and formic acid production, as the first proof of concept

Summary

Introduction

Research interest in renewable fuels has intensified over the last two decades due to the finiteness of fossil fuels and concern about their environmental issues (IPCC, 2014). There has been a particular focus on the production of renewable fuels and chemicals from waste, as it does enable the reuse of an otherwise insignificant stream to maximise utility and capacitates the realisation of a circular Nomenclature q SD φa,φi. COD Consumption rate in the biofilm (kgCOD kgVS−1 day−1), VS = Volatile solids as a measure of biomass COD (substrate) concentration (kgCOD cm−3). Electron equivalence of substrate time conversion factor (s day−1). Constants of the linear applied potential-related function rate of active biomass inactivation (day−1) rate of formic acid production (mg L−1 hr−1). Faradic efficiency for formic acid production (%). Number of electrons transferred per mole of formic acid molar flux of substrate passing through the biofilm (kgCOD cm−2 day−1) Volumetric fraction of active and inactive biomass (dimensionless) universal gas constant and Faraday constant advective velocity (cm−2 day−1) specific rate of endogenous respiration (day−1) diffusion coefficient of substrate in the biofilm (cm day−1) density of active and inactive biomass (kgVS cm−3) current density (mA cm−2) biofilm conductivity (Sm−1)

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