Microbial desalination cell technology: A review and a case study

The microbial desalination cell (MDC) is a newly-developed technology which integrates the microbial fuel cell (MFC) process and electrodialysis for wastewater treatment, water desalination and production of renewable energy. Due to free energy requirements and environmentally friendly technologies, MDC recently received considerable attention for desalination and wastewater treatment. The technology can either be used as a stand-alone process, or can be combined with other desalination processes, such as reverse osmosis (RO) or electrodialysis. Recently, several different modifications of MDCs have been developed including stacked MDCs, biocathode MDCs and recirculation MDCs. This paper provides a general review of the MDC technology. The working principle of the conventional MDC system is discussed, followed by a brief introduction to biofilms and biofilm formation. The different modifications of MDCs and the various advantages and disadvantages associated with each, including the desalination performance and electricity generation are also considered. The issues of scale-up and practical availability of the MDC technology are discussed, followed by a detailed discussion and evaluation of a proposed design for a wastewater treatment plant integrating the MDC technology. A case study of a wastewater treatment plant integrated with MDC technology to simultaneously treat wastewater and desalinate seawater is also considered. © 2014 Elsevier B.V. All rights reserved.

Microbial desalination cell (MDC) is an upcoming technology which can minimize power consumption and recover increased desalinated water when installed as a pre-desalination unit. MDCs produce their own electricity while treating wastewater and desalinating water simultaneously by exposing the organic matter in waste water to exoelectrogenic bacteria. Various MDCs, that can be further extended to real waste water plants for economic affordability and saving energy, have been briefly discussed in this paper. The study on MDCs was further extended by considering a case study which integrates this technology into a wastewater treatment plant and evaluating different alternatives for this proposed plant. It can be said that MDCs are a novel technique for treating waste water and desalinating seawater; a technique capable of minimizing capital costs and simultaneously increasing the treatment efficiency of treatment plants. List of abbreviations AEM Anion-exchange membrane BAC BPM–AEM–CEM stack structure BPM Bipolar membrane CEM Cation-exchange membrane CE Coulombic efficiency c-SMDC-S Stacked circulation microbial desalination cell DR Desalination rate FO Forward osmosis IEMs Ion-exchange membranes MDC Microbial desalination cell MEDC Microbial electrolysis desalination cell MEDCC Microbial electrolysis desalination and chemical-production cell MFC MSF PBS R-MDC PRO RO rMDC SEM TDS UMDC Microbial fuel cell Multistage flash desalination Phosphate buffer solution Ion-exchange resin coupled microbial desalination cell Pressure retarded osmosis Reverse osmosis Re-circulation microbial desalination cell Scanning electron microscope Total dissolved solid Upflow MDC