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  • Rogers Drake posted an update 16 hours, 39 minutes ago

    Water reclamation and ecological reuse is gradually becoming a popular solution to address the high pollutant loads and insufficient ecological flow of many urban rivers. However, emerging contaminants in water reuse system and associated human health and ecological risks need to be assessed. This study determined the occurrence and human health and ecological risk assessments of 35 emerging contaminants during one year, including 5 types of persistent organic pollutants (POPs), 5 pharmaceutical and personal care products (PPCPs), 7 endocrine disrupting chemicals (EDCs) and 18 disinfection by-products (DBPs), in a wastewater treatment plant (WWTP) and receiving rivers, as well as an unimpacted river for comparison. Results showed that most of PPCPs and EDCs, especially antibiotics, triclosan, estrogens and bisphenol A, occurred frequently at relatively high concentrations, and they were removed from 20.5% to 88.7% with a mean of 58.9% via WWTP. The highest potential noncarcinogenic and carcinogenic risks in different reuse scenarios were assessed using maximal detected concentrations, all below the acceptable risk limits, with the highest total combined risk value of 9.21 × 10-9 and 9.98 × 10-7, respectively. Ecological risk assessment was conducted using risk quotient (RQ) method and indicated that several PPCPs, EDCs and haloacetonitriles (HANs) pose high risk (RQ > 1) to aquatic ecology in the rivers, with the highest RQ up to 83.8. The study suggested that ecological risks need to be urgently addressed by updating and optimizing the process in WWTPs to strengthen the removal efficiencies of emerging contaminants. The study can serve as a reference for safer water reuse in the future, while further studies could be conducted on the health risk of specific groups of people, exposure parameters in water reuse, as well as more emerging contaminants.The present paper describes the assessment of the atmospheric deposition processes in a basin valley through a multidisciplinary approach based on the data collected within an extensive physico-chemical characterization of the soils, combined with the local meteorology. Surface soil cores were collected on a NNW-SSE transect across the Terni basin (Central Italy), between the Monti Martani and the Monti Sabini chains (956 m a.s.l.), featuring the heavily polluted urban and industrial enclave of Terni on its bottom. Airborne radiotracers, namely 210Pb and 137Cs, have been used to highlight atmospheric deposition. We observed an increased deposition flux of 210Pb and 137Cs at sites located at the highest altitudes, and the associated concentration profiles in soil allowed to evaluate the role of atmospheric deposition. We also obtained a comprehensive dataset of stable anthropogenic pollutants of atmospheric origin that showed heterogeneity along the transect. SHP099 price The behavior has been explained by the local characteristic of the soil, by seeder-feeder processes promoted by the atmospheric circulation, and was reconciled with the concentration profile of radiotracers by factor analysis. Finally, the substantial impact of the local industrial activities on soil profiles and the role of the planetary boundary layer has been discussed and supported by simulations employing a Lagrangian dispersion model.The emerging contaminants, in particular pharmaceuticals and personal care products and environmental estrogens, have been received global concerns in recent years. Nanofiltration (NF) as an advanced tertiary treatment technology can be a reliable and potential tool for micropollutants removal. However, the influence of operation conditions of NF system to micropollutants rejections in an engineering application, is still lacking. Here, a pilot-scale NF system was set up to investigate its removal efficiencies to 49 micropollutants under different operation conditions by treating actual municipal wastewater. The results showed that the rejections of positively and neutrally charged micropollutants with molecular weight higher than 250 g mol-1 were both higher than 80%. Besides, most negatively charged micropollutants were also rejected higher than 80% under different operation conditions. The rejections of most micropollutants increased with temperature decreased from 25 °C to 13 °C, which was primarily ascribed to decrease of pore size of NF membrane at low temperature. Compared with the water recovery rate of 80%, lower rejections of micropollutants were observed with lower water recovery rate of 60%. Except for sulfamethoxazole, the risk quotients of other detected 20 micropollutants in NF effluent were all lower than 1.0, showing medium or no risks to aquatic organisms. This study might aid understanding the performance of micropollutants rejections by NF in actual engineering application and could give guideline to the implementation of NF technology in future advanced treatment processes.Lignocellulose-amended, layered soil treatment areas (STAs) remove nitrogen (N) passively from wastewater by sequential nitrification and denitrification. As wastewater percolates through the STA, the top sand layer promotes nitrification, and the lower, lignocellulos-amended sand layer promotes heterotrophic denitrification. Layered STAs can remove large amounts of N from wastewater, which may increase their emissions of CO2, N2O, and CH4 to the atmosphere. We measured greenhouse gas (GHG) flux from sawdust-amended (Experimental) and sand-only (Control) STAs installed in three homes in southeastern Massachusetts, USA. The Experimental STAs did not emit significantly more GHGs to the atmosphere than Control STAs receiving the same wastewater inputs, and both Control and Experimental STAs emitted more CO2 and N2O – but not CH4 – than soil not treating wastewater. Median (range) flux (μmol m-2 s-1) for all homes for the Control STAs was 7.6 (0.8-23.0), 0.0001 (-0.0004-0.004), and 0.0008 (0-0.02) for CO2, CH4 and N2O, respectively, whereas values for the Experimental STAs were 6.6 (0.3-24.3), 0 (-0.0005-0.005), and 0.0004 (0-0.02) for CO2, CH4 and N2O, respectively. Despite the absence of differences in flux between Control and Experimental STAs, the Experimental STA had significantly higher subsurface GHG levels than the Control STA, suggesting microbial consumption of excess gas levels near the ground surface in the Experimental STA. The flux of GHGs from Experimental and Control STAs was controlled chiefly by temperature, soil moisture, and subsurface GHG concentrations. Total emissions (gCO2e capita-1 day-1) were higher than those reported by others for conventional STAs, with mean values ranging from 0 to 1835 for septic tanks, and from 30 to 1938 for STAs. Our results suggest that, despite a higher capacity to remove N from wastewater, layered STAs may have limited impact on air quality compared to conventional STAs.

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