An improved insight into the effect of powdered activated carbon (PAC) on membrane fouling is crucial to the MBR performance. Sludge key property, soluble microbial products (SMP) and transmembrane pressure (TMP) were monitored. The membrane fouling rate in the MBRs was also analyzed based on TMP profile and resistance-in-series model. PAC reduced the membrane filtration resistance and significantly decreased the fouling rate. The sludge filterability was improved by extending the filtration time by almost twofold. PAC affected the SMP release and protein/polysaccharide (carbohydrate) was in a lower ratio. Fourier transform infrared (FTIR) analysis indicated that PAC decreased the impact of organic carbon, and reduced the proteins’ and polysaccharides’ absorption and deposition on the membrane surface and in the pores. The degree of reversible and irreversible fouling was related to the PAC content added into the MBRs. At the optimum dosage of 2 g/L, the results signified the PAC potential as a mitigation strategy of membrane fouling.

Surface-water extent can change rapidly in densely populated river–lake regions, where hydrological variability and land-use change occur simultaneously. Changes in total surface-water area alone, however, do not fully reveal the land-use processes underlying local gains and losses. We examined annual surface-water dynamics from 2017 to 2024 and identified the land-use transitions associated with surface-water gain and loss in the middle Yangtze River region around Wuhan, China. Annual 10 m land-cover data were used to quantify changes in surface-water extent and its bidirectional transitions with cropland, urban land, forests, grasslands, and barren land. Spatial analyses were used to characterize the distribution of surface-water change, while partial least squares structural equation modeling (PLS-SEM) was applied to examine direct and indirect associations between surface-water gain or loss and selected physiographic and human-related factors. Surface-water extent fluctuated but increased overall by 757.42 km², or 9.48%, reaching 8744.02 km² in 2024. The most intensive bidirectional transition occurred between surface water and cropland: 1506.16 km² of cropland was converted to surface water, whereas 562.36 km² of surface water was converted to cropland. An additional 162.15 km² of surface water was converted to urban land, with these losses concentrated around urbanized areas and water-body margins. The PLS-SEM models yielded different patterns of estimated associations between surface-water gain or loss and the selected terrain, precipitation, accessibility-related, agricultural, economic, and social constructs. The results show that a regional net increase in surface-water extent can coexist with substantial local gains, losses, and bidirectional exchanges with surrounding land-use systems. Distinguishing these transition pathways can provide a more informative basis for interpreting regional surface-water dynamics and supporting water-resource planning and management than net area statistics alone, particularly in agricultural–water and urban–water transition zones.