No abstract

Full-scale wastewater treatment facilities are not able to prevent microplastics (MPs) from discharging into natural waters and they are also associated with the land application of the sludge. This study evaluates the distribution of microfibers (MFs) in a lab-scale sequencing batch reactor (SBR) fed by synthetic wastewater (SW) for 93 days. The MFs were analyzed through optical microscopy in the mixed liquor (ML) and the effluent, and sulfuric acid digestion was applied to discriminate between natural and synthetic MFs (i.e., MPs). The results of the optical microscopy analyses were further validated through FTIR spectroscopy. A model describing the evolution over time of the MF concentration in the ML was created, accounting for the MFs entering the system through the SW and atmospheric deposition. The ratio between the MF concentration in the ML and the effluent was 1409 ± 781, demonstrating that MFs settle with the sludge. Consistently, in the ML, 64.9% of the recovered MFs were smaller than 1000 µm (average size 968 µm), while in the effluent, 76.1% of MFs were smaller than 1000 µm (average size 772 µm). Overall, 72% of MFs recovered from the ML were natural fibers and sulfuric acid digestion was successful in eliminating the natural MFs.

No abstract

Hydropower (HP) is a key source of renewable energy, but also poses significant environmental challenges, including habitat fragmentation, hydropeaking and perturbations of flow and sediment regime. This study analyzed how Italian companies managing HP plants, and registered to the European Eco-Management and Audit Scheme (EMAS) in 2022, evaluated their sustainability and publicly disclosed related data. The analysis was based on the environmental statements (ESs) of 206 hydropower plants (29% of Italian HP production in 2019). The applied methodology involved an inventory of the plants and their categorization about technical features and the reporting of technical, environmental, and social aspects. The results of the analysis revealed that the companies rarely described the environmental state of the site, even less frequently adopting quantitative indicators. “Soil contamination”, “biodiversity”, “waste production”, “risk of environmental accidents”, “water pollution and flow management”, and “noise emissions” were the aspects considered most significant. No correlation was found among the significance of an aspect, the number of indicators used to describe the associated impacts, and the number of objectives set for reducing those impacts. “Biodiversity” was mostly described through irrelevant indicators (i.e., total site area) and 76% of the allocated budget was assigned to technical aspects without a clear connection with any environmental improvement. In particular, the specific impacts on the aquatic ecosystems were scarcely reported, mitigation measures were rarely mentioned and with few details. In conclusion, the results of the study highlight the need for specific guidelines, directed to the HP sector, for effectively reporting the environmental performances and the effectiveness of the adopted Environmental Management Systems, while providing valuable information to policymakers and researchers.

No abstract