An Overview of Microbial Fuel Cells within Constructed Wetland for Simultaneous Nutrient Removal and Power Generation

Abstract

Water, energy, and food are indispensable for sustainable economic development. Despite nutrients, especially phosphorus and nitrogen, being essential for plant growth and thus food supplies, those present in wastewater are considered an environmental burden. While microbial fuel cells (MFCs) are receiving much interest, combining wastewater treatment with an MFC has emerged as an option for low-cost wastewater treatment. Among others, a constructed wetland (CW) coupled with an MFC (CW-MFC) has the potential to provide a low carbon footprint and low-energy wastewater treatment, as well as nutrient and energy recovery from wastewater. Findings from this review show that the organic and nutrient removal and power generation by the integrated CW-MFC systems are affected by a number of factors including the organic loading rate, hydraulic retention time, system design, plant species, dissolved oxygen, substrate/media type, influent feeding mode, electrode materials and spacing, and external resistance. This review aims to summarize the current state of the CW-MFC and related technologies with particular emphasis on organic and nutrient removal, as well as on the bioenergy recovery from different wastewaters. Despite the benefits that these technologies can offer, the interactive mechanisms between the CW and MFC in the integrated system are still unclear. Further research is needed to fully understand the CW-MFC and related systems. The results of this work provide not only an overview and insight into existing knowledge but also the future direction of the CW-MFC technologies.

Coupling Microbial Fuel Cell and Hydroponic System for Electricity Generation, Organic Removal, and Nutrient Recovery via Plant Production from Wastewater

“…The lower ammonium level in the Hyp might have occurred owing to enhanced nitrification and nitrate uptake by A. tuberosum. Previous researchers have shown that plants in the cathode region could be beneficial for ammonium removal and bioelectricity generation [25,41,42]. Undoubtedly, further studies are required to fully understand the nitrogen removal pathways in the MFC-Hyp system.…”

“…Microbial fuel cells (MFCs) are bioelectrochemical systems capable of using wastewater as an energy source to generate electricity while treating wastewater. MFCs have attracted considerable attention due to their versatility in their applications in wastewater treatment, power generation, environmental sensors, nutrient recovery, and many more [5,18,[23][24][25][26][27]. In principle, a single chamber MFC consists of an anode, cathode, microorganisms, substrate (anolyte), and conductive wire (external circuit).…”

“…In a hydroponic system, nutrients in water and carbon dioxide in the air can be captured and stored as biomass in plants, while oxygen is produced via photosynthesis. Thus, hydroponic systems are considered an environmentally friendly technology that can be applied to wastewater reuse, while improving water quality [25,33]. The goal of this research was to develop a novel sustainable energy generation-resource recovery system by coupling an MFC with hydroponics (Hyp).…”

Phytoremediation Performance with Ornamental Plants in Monocultures and Polycultures Conditions Using Constructed Wetlands Technology

“…The ability of CWs to remove organic matter, nitrogen and phosphorus compounds, emerging pollutants (antibiotics, human and veterinary pharmaceuticals, personal-care products, etc. ), pesticides of agricultural runoff, and coliforms from wastewater has been studied extensively around the world, especially in the U.S.A. and Europe, resulting in high-efficiency levels [5][6][7] or in simultaneous nutrient removal and power generation [8,9]. In addition, CWs are cost-effective, and maintenance costs are less when compared to conventional treatment systems [10].…”

Integrating Microbial Fuel Cell and Hydroponic Technologies Using a Ceramic Membrane Separator to Develop an Energy–Water–Food Supply System

“…Because of a lack of physical separation between the anode and the cathode in the CW-MFC, the diffusion of O 2 into the anodic zone causes a significant loss of electrons, resulting in low power outputs [ 28 ]. A detailed review of CW-MFC is available in the literature [ 29 ].…”