Performance of pilot-scale constructed wetland osmotic microbial fuel cell under different gravel conditions

Advancement in constructed wetland microbial fuel cell process for wastewater treatment and electricity generation: a review

The constructed wetland coupled with a microbial fuel cell (CW-MFC) is a wastewater treatment process that combines contaminant removal with electricity production, making it an environmentally friendly option. This hybrid system primarily relies on anaerobic bioprocesses for wastewater treatment, although other processes such as aerobic bioprocesses, plant uptake, and chemical oxidation also contribute to the removal of organic matter and nutrients. CW-MFCs have been successfully used to treat various types of wastewater, including urban, pharmaceutical, paper and pulp industry, metal-contaminated, and swine wastewater. In CW-MFC, macrophytes such as rice plants, Spartina angalica, Canna indica, and Phragmites australis are used. The treatment process can achieve a chemical oxygen demand removal rate of between 80 and 100%. Initially, research focused on enhancing power generation from CW-MFC, but recent studies have shifted towards resource recovery from wastewater. This review paper provides an overview of the development of constructed wetland microbial fuel cell technology, from its early stages to its current applications. The paper also highlights research gaps and potential directions for future research.

Simultaneous Wastewater Treatment and Resources Recovery by Forward Osmosis Coupled with Microbial Fuel Cell: A Review

Osmotic microbial fuel cells (OsMFCs) with the abilities to simultaneously treat wastewater, produce clean water, and electricity provided a novel approach for the application of microbial fuel cell (MFC) and forward osmosis (FO). This synergistic merging of functions significantly improved the performances of OsMFCs. Nonetheless, despite their promising potential, OsMFCs currently receive inadequate attention in wastewater treatment, water reclamation, and energy recovery. In this review, we delved into the cooperation mechanisms between the MFC and the FO. MFC facilitates the FO process by promoting water flux, reducing reverse solute flux (RSF), and degrading contaminants in the feed solution (FS). Moreover, the water flux based on the FO principle contributed to MFC's electricity generation capability. Furthermore, we summarized the potential roles of OsMFCs in resource recovery, including nutrient, energy, and water recovery, and identified the key factors, such as configurations, FO membranes, and draw solutions (DS). We prospected the practical applications of OsMFCs in the future, including their capabilities to remove emerging pollutants. Finally, we also highlighted the existing challenges in membrane fouling, system expansion, and RSF. We hope this review serves as a useful guide for the practical implementation of OsMFCs.

Development of microbial fuel cell integrated constructed wetland (CMFC) for removal of paracetamol and diclofenac in hospital wastewater

Hospital wastewater management has become a significant concern across the globe due to the presence of pharmaceutically active compounds (PhACs) and other toxic substances, which can potentially disrupt ecosystems. The presence of recalcitrant PhACs in hospital wastewater increases the difficulty level for conventional wastewater treatment systems. Furthermore, incorporating advanced oxidation-based treatment systems increase capital and operation costs. To reduce treatment costs, low-cost innovative technology, i.e., composite constructed wetland and microbial fuel cell system (CMFC), has been developed for higher treatment efficiency of PhACs in hospital wastewater along with simultaneous bioelectricity generation as an additional outcome. In this study, influencing operating parameters, such as initial chemical oxygen demand (COD), electrode spacing, and substrate-to-water-depth ratio, were optimized for two plant species: water hyacinth (WH) and duckweed (DW). The optimized systems were run in batch and continuous mode for WH-CMFC and DW-CMFC to treat synthetic hospital wastewater with paracetamol and diclofenac, and the bioelectricity generation was monitored. DW-CMFC system depicted better treatment efficiency and voltage generation as compared to WH-CMFC. In continuous mode, the DW-CMFC system exhibited a removal of 95.3% COD, 97.1% paracetamol, and 87.5% diclofenac. WH-CMFC and DW-CMFC achieved power densities of around 21.26 mW/m2 and 42.93 mW/m2, respectively. The fate of PhACs during and after treatment and toxicity analysis of the transformation products formed were also carried out. Higher bio-electricity generation and efficient wastewater treatment of the DW-CMFC make it a sustainable option for hospital wastewater management.

The race between classical microbial fuel cells, sediment-microbial fuel cells, plant-microbial fuel cells, and constructed wetlands-microbial fuel cells: Applications and technology readiness level

Microbial fuel cell (MFC) is an interesting technology capable of converting the chemical energy stored in organics to electricity. It has raised high hopes among researchers and end users as the world continues to face climate change, water, energy, and land crisis. This review aims to discuss the journey of continuously progressing MFC technology from the lab to the field so far. It evaluates the historical development of MFC, and the emergence of different variants of MFC or MFC-associated other technologies such as sediment-microbial fuel cell (S-MFC), plant-microbial fuel cell (P-MFC), and integrated constructed wetlands-microbial fuel cell (CW-MFC). This review has assessed primary applications and challenges to overcome existing limitations for commercialization of these technologies. In addition, it further illustrates the design and potential applications of S-MFC, P-MFC, and CW-MFC. Lastly, the maturity and readiness of MFC, S-MFC, P-MFC, and CW-MFC for real-world implementation were assessed by multicriteria-based assessment. Wastewater treatment efficiency, bioelectricity generation efficiency, energy demand, cost investment, and scale-up potential were mainly considered as key criteria. Other sustainability criteria, such as life cycle and environmental impact assessments were also evaluated.