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.

A biological treatment is the core process for removing organic pollutants from industrial wastewater. However, industrial wastewater often contains large amounts of toxic and harmful pollutants, which can inhibit the activity of microorganisms in a treatment system, precipitate the deterioration of effluent quality, and threaten water ecological security from time to time. In most of the existing anaerobic biological treatment processes, toxic effects on microorganisms are determined according to the amounts of end-products of the biochemical reactions, and the evaluation results are relatively lacking. When microorganisms contact toxic substances, changes in biological metabolic activity precede the accumulation of reaction products. As sensitive units, electroactive microorganisms can generate electrical signals, a change in which can directly reflect the toxicity level. The applications of electroactive microorganisms for the toxicity monitoring of wastewater are very promising. Further attention needs to be paid to considering the appropriate evaluation index, the influence of the environment on test results, mechanisms, and other aspects. Therefore, we reviewed the literature regarding the above aspects in order to provide a research foundation for the practical application of electroactive microorganisms in toxicant monitoring.

To ensure water source security and sustainability of the national major strategic project “South-to-North Water Diversion”, this study aims to evaluate the spatio-temporal evolution characteristics of the ecosystem service value (ESV) in its water source area from 2002 to 2022. This study reveals its changing trends and main influencing factors, and thereby provides scientific support for the ecological protection and management of the water source area. Quantitative assessment of the ESV of the region was carried out using the Equivalence Factor Method (EFM), aiming to provide scientific support for ecological protection and resource management decision-making. In the past 20 years, the ESV has shown an upward trend year by year, increasing by 96%. The regions with the highest ESV were Garzê Prefecture and Aba Prefecture, which increased by 130.3% and 60.6%, respectively. The ESV of Xinlong county, Danba county, Rangtang county, and Daofu county increased 4.8 times, 1.5 times, 12.5 times, and 8.9 times, respectively. In the last two decades, arable land has decreased by 91%, while the proportions of bare land and water have decreased by 84% and 91%, respectively. Grassland had the largest proportion. Forests and grasslands, vital for climate regulation, water cycle management, and biodiversity conservation, have expanded by 74% and 43%, respectively. It can be seen from Moran’s I index values that the dataset as a whole showed a slight positive spatial autocorrelation, which increased from −0.041396 to 0.046377. This study reveals the changing trends in ESV and the main influencing factors, and thereby provides scientific support for the ecological protection and management of the water source area.

The Western Route of the South-to-North Water Diversion Project is a significant water conservancy project that has undergone years of discussion. This study employed the emergy method to evaluate the ecosystem service value (ESV) of its water source areas from 2002 to 2022, analyzing spatial heterogeneity, and evaluating trade-offs and synergies among ecosystem services. The high-emergy areas for water supply are concentrated in the lower reaches of the basin, Liangshan Prefecture had the highest emergy, increasing from 1.14 × 10²¹ sej to 1.65 × 10²¹ sej over the 20 years. The climate regulation emergy values of Ganzi Prefecture, Aba Prefecture, and Liangshan Prefecture were relatively stable. The biodiversity remained relatively stable with small fluctuations, but exhibited significant spatial heterogeneity. Liangshan Prefecture and Lijiang City had the highest biodiversity emergy values, at 1.21 × 10²¹ sej and 2.05 × 10²¹ sej respectively, corresponding to as many as 7661 and 13,000 species, respectively. Among the service types, provisioning services and supporting services account for a relatively high proportion. The water supply increased by 6.13%, while the biodiversity decreased by 5.42%. The relationship showed particularly intense conflict of −0.965. Analyzing the spatiotemporal evolution of ESV in water source areas is of great significance for rationally guiding the phased and seasonal allocation of water transfer volumes, implementing ecological compensation, and assessing the impacts of water conservancy projects on the ecological environment.

This study discussed the influence of acetate and sodium chloride concentration on monitoring 2,4-dichlorophenol(2,4-DCP) by electroactive bacteria. The performance of the reactor was represented by power density, and the electrochemical activity was represented by redox capacity. At the same time, micro-electrodes were used to detect the redox potential between biofilms, and the changes in extracellular polymers and microbial community structure under different conditions were also explored. With acetate concentration of 1 g/L and sodium chloride concentration of 0.0125 g/L, the electroactive microorganisms were more sensitive to toxic substances and responded fast. The biofilm also evenly covered on the surface of the carrier, which aided in the diffusion of substances. Although the maximum power density monotonically increased with acetate concentration, high concentration of substrate may mask the inhibitory effect and affect the judgment of inhibitory results. The content of protein and polysaccharide increased monotonically with sodium chloride concentration. However, more polysaccharides would lead to high resistance to electron transfer. Compared to sodium chloride, the microbial content was more affected by acetate. The electroactive microorganisms had strong adaptability to salinity. In practical application, it is conducive to increase the sensitivity of MFCs to reasonably reduce the concentration of acetic acid and sodium chloride.

The water self-purification capacity in the source area of the Western Route of the South-to-North Water Diversion Project of China was investigated. This research aimed to promote the coordinated development of water source protection and water diversion benefits. Based on water quality tests conducted in the upstream section of the water source area, the results indicate that the water quality in the upper reaches of the water source region is generally good. However, total nitrogen at some sites in the Dadu River basin exceeded 1.0 mg/L, and the mean total nitrogen concentration in the Dadu River basin was higher than that in the Yalong River basin, while total phosphorus levels remained low in both basins. The nitrogen removal of the Yalong River Basin and the Dadu River Basin attained a peak of 34,654 t in 2012. The nitrogen removal was more than ten times that of phosphorus. Among the prefectures, the water self-purification service value ranks as follows: Garzê > Liangshan > Aba > Golog. The correlations between water quality indicators and driving factors-including land use types, GDP, precipitation, population, and temperature were discussed. In terms of spatial drivers, barren land (r = 0.41) and grassland (r = 0.47) are the major land-use contributors to TN. The model was found which can be used to quantify management priorities and predict potential risks associated with nitrogen pollution. After water diversion, the removal of nitrogen and phosphorus in the water source area declined, which was not linearly related to the amount of water diverted.