The Catholyte Effects on The Microbial Desalination Cell Performance of Desalination and Power Generation

Suhad Shamil Jaroo,Talib Rashid Abbas,Ghufran Farooq Jumaah

doi:10.31026/j.eng.2021.07.05

Abstract

A microbial desalination cell (MDC) is a new approach to bioelectrochemical systems. It provides a more sustainable way to electrical power production, saltwater desalination, and wastewater treatment at the same time. This study examined three operation modes of the MDC: chemical cathode, air cathode, and biocathode MDC, to give clear sight of this system's performance. The experimental work results for these three modes were recorded as power densities generation, saltwater desalination rates, and COD removal percentages. For the chemical cathode MDC, the power density was 96.8 mW/m2, the desalination rate was 84.08 ppm/hr, and the COD removal percentage was 95.94%. The air cathode MDC results were different; the power density was 24.2 mW/m2, the desalination rate was 86.11 ppm/hr, and the COD removal percentage was 91.38%. The biocathode MDC results were 19.91 mW/m2 as the power density, 88.9 ppm/hr as the desalination rate, and 96.94% as the COD removal percentage. The most efficient type of MDC in this study in power production was the chemical cathode MDC, but it is the lowest sustainable. On the other hand, the biocathode MDC was the best in desalination process performance, and both the air cathode and biocathode MDC are more sustainable and environmentally friendly, especially the biocathode MDC.

Highlights

The world suffers from the increasing urban water shortage, so water reuse and desalination became necessary and useful in many countries, especially Iraq
This study aims to investigate the best way to operate the microbial desalination cell (MDC) system by many experiments with a different type of catholyte and recording the characteristics and working conditions of all MDC types presented by saltwater desalination system performance, wastewater treatment, and electric power generation
These two figures show that the maximum voltage difference between the electrodes in the anode and cathode chamber for a fixed value of the external electrical resistance at 100 Ω was 280 mV, 140 mV, and 127 mV for the chemical cathode, air cathode, and biocathode MDC, respectively; for six days of each experiment

Summary

Introduction

The world suffers from the increasing urban water shortage, so water reuse and desalination became necessary and useful in many countries, especially Iraq. The technologies of wastewater treatment and desalination are costly and energy-waste. The most common wastewater treatment process is the activated sludge process, requiring high capital and maintenance costs in addition to large amounts of energy (Gude, 2015b). Conventional desalination technology expends large amounts of energy too. The most efficient seawater desalination system is the reverse osmosis process, and the energy required to accomplish this process of only 1.8–2.2 kWh/ m3. There is a persistent need to progress new and proceeding water purification technologies with low cost for both wastewater treatment and desalination purposes to increase freshwater supplies (Gude, 2017, 2018)

Objectives

Methods

Results

Conclusion