Aquaporin-based forward osmosis (AQP FO) membranes were applied both in laboratory- and pilot-scale for removing micropollutants from water. The effect of operating parameters (feed flow, draw flow, and transmembrane pressure) on the i) rejection of micropollutants, ii) water flux, iii) reverse salt flux, and iv) water recovery of the AQP FO membrane modules was studied. Among the 21 micropollutants spiked, only four compounds, atenolol, propranolol, metoprolol, and citalopram, permeated through the AQP FO membranes to an extent that they could be quantified in the draw solutions of both the laboratory and pilot systems. The rejection rates, based on the full mass balance calculations, were between 96.1% and 99.7%, and all the other 17 compounds showed rejection exceeding 90% on both systems. The pilot AQP FO system was further employed for six days to treat effluent from a membrane bioreactor (MBR) treating municipal wastewater. 35 micropollutants were investigated. 27 of these were identified and quantified in the MBR effluent. Minute fractions of gabapentin, benzotriazole, and metoprolol were detected passing through the AQP FO membranes into the draw side with a constant rejection of around 99.2%, 95.4%, and 99.9%. Almost all other micropollutants' minimum rejection rates exceeded 80%.The effects of anaerobic digestion (AD) on the abundance of antibiotic resistance genes (ARGs) are highly related to operational temperature. However, the removal performance of ARGs in psychrophilic AD and changed temperatures simulating variable seasonal temperatures is poorly understood. Herein, we investigated the fate of ARGs, correlated bacterial communities and physicochemical properties of AD operation at psychrophilic (15 ℃), mesophilic (35 ℃), and temperature changed conditions (15 to 35 ℃ and 35 to 15 ℃). https://www.selleckchem.com/products/bmn-673.html The results indicated that ammonia release was positively correlated with temperature. The mesophilic AD facilitated phosphorous intake and ARGs proliferation and selection with oxytetracycline (OTC), while psychrophilic AD was conducive to the removal and control of ARGs if no OTC existed. The diversity and composition of AD bacterial communities were influenced more by temperature than OTC. The dominant genera like Candidatus_Microthrix and Acinetobacter had dramatical abundance discrepancies at different temperatures and were obviously positively correlated with ARGs (tet39, tetC and mexD), mobile genetic elements (MGEs) intI, insert sequences (IS) and plasmid. The physicochemical properties of AD influenced the bacterial richness, which in turn significantly correlated with the ARGs abundances. Therefore, ARGs removal could be potentially optimized by eliminating bacterial hosts with deteriorated living conditions and decreased nutrients. This study clarified the response of antibiotic resistome to different temperature variation and highlighted the potential strategies for improved ARGs removal in AD.Due to the fast reaction of superoxide radical (O2•-) with ozone (O3), it has been suggested that O2•- is present at very low concentrations during ozonation. Therefore, while O2•- has been considered a critical chain carrier for promoting O3 decomposition to hydroxyl radicals (•OH), the direct reactions of O2•- with micropollutants have been assumed to be insignificant during ozonation. In this study, we monitored the exposures of O3, •OH, and O2•- by following the depletion of O3, p-chlorobenzoic acid (pCBA, as •OH probe), and tetrachloromethane (CCl4, as O2•- probe) during ozonation of various water matrices (surface water, groundwater, and secondary wastewater effluent). For a given water matrix, the ratio between •OH and O3 exposures (Rct), O2•- and O3 exposures (RSO), as well as O2•- and •OH exposures (RSH) remained almost constant over the entire reaction time. This suggests that during ozonation, the ratios between the transient concentrations of •OH and O3, O2•- and O3, and O2•- and •OH were also constant and equaled to the Rct, RSO, and RSH, respectively. Based on the O3, •OH, and O2•- exposures observed during ozonation, a chemical kinetic model was proposed to simulate the abatement of ten ozone-resistant micropollutants in the three water matrices by ozonation. The results indicate that due to the higher concentrations of O2•- than •OH (RSH = ~5-8), the reactions with O2•- played a non-negligible or even dominant role in the abatement of some micropollutants that have similar or higher O2•- reactivity than •OH reactivity (e.g., tetrachloroethylene, chloroform, and PFOA). Compared with the previous model that neglected the contribution of O2•- to micropollutant abatement, the proposed model more accurately simulated the abatement efficiencies of the test micropollutants during ozonation. These results indicate that the proposed model can provide a useful tool for the generalized prediction of micropollutant abatement by ozonation.Reservoirs have been constructed as clean energy sources in recent decades with various environmental impacts. Karst rivers typically exhibit high dissolved inorganic carbon (DIC) concentrations, whether and how reservoirs affect carbon cycling, especially organic carbon (OC)-related biogeochemical processes in karst rivers, are unclear. To fill this knowledge gap, multiple tracer methods (including fluorescence excitation-emission matrix (EEM), ultraviolet (UV) absorption, and stable carbon (δ13C) and radiocarbon (Δ14C) isotopes) were utilized to track composition and property changes of both particulate OC (POC) and dissolved OC (DOC) along river-transition-reservoir transects in the Southwest China karst area. The changes in chemical properties indicated that from the river to the reservoir, terrestrial POC is largely replaced by phytoplankton-derived OC, while gradual coloured dissolved organic matter (CDOM) removal and addition of phytoplankton-derived OC to the DOC pool occurred as water flowed to the reservoir. Higher primary production in the transition area than that in the reservoir area was observed, which may be caused by nutrient released from suspended particles. Within the reservoir, the production surpassed degradation in the upper 5 m, resulting in a net DIC transformation into DOC and POC and terrestrial DOM degradation. The primary production was then gradually weakened and microbial degradation became more important down the profile. It is estimated that ~3.1-6.3 mg L-1 (~15.5-31.5 mg-C m-2 (~10-21%)) DIC was integrated into the OC pool through the biological carbon pump (BCP) process in the upper 5 m in the transition and reservoir areas. Our results emphasize the reservoir impact on riverine OC transport, and due to their characteristics, karst areas exhibit a higher BCP potential which is sensitive to human activities (more nutrient are provided) than non-karst areas.
Aquaporin-based forward osmosis (AQP FO) membranes were applied both in laboratory- and pilot-scale for removing micropollutants from water. The effect of operating parameters (feed flow, draw flow, and transmembrane pressure) on the i) rejection of micropollutants, ii) water flux, iii) reverse salt flux, and iv) water recovery of the AQP FO membrane modules was studied. Among the 21 micropollutants spiked, only four compounds, atenolol, propranolol, metoprolol, and citalopram, permeated through the AQP FO membranes to an extent that they could be quantified in the draw solutions of both the laboratory and pilot systems. The rejection rates, based on the full mass balance calculations, were between 96.1% and 99.7%, and all the other 17 compounds showed rejection exceeding 90% on both systems. The pilot AQP FO system was further employed for six days to treat effluent from a membrane bioreactor (MBR) treating municipal wastewater. 35 micropollutants were investigated. 27 of these were identified and quantified in the MBR effluent. Minute fractions of gabapentin, benzotriazole, and metoprolol were detected passing through the AQP FO membranes into the draw side with a constant rejection of around 99.2%, 95.4%, and 99.9%. Almost all other micropollutants' minimum rejection rates exceeded 80%.The effects of anaerobic digestion (AD) on the abundance of antibiotic resistance genes (ARGs) are highly related to operational temperature. However, the removal performance of ARGs in psychrophilic AD and changed temperatures simulating variable seasonal temperatures is poorly understood. Herein, we investigated the fate of ARGs, correlated bacterial communities and physicochemical properties of AD operation at psychrophilic (15 ℃), mesophilic (35 ℃), and temperature changed conditions (15 to 35 ℃ and 35 to 15 ℃). https://www.selleckchem.com/products/bmn-673.html The results indicated that ammonia release was positively correlated with temperature. The mesophilic AD facilitated phosphorous intake and ARGs proliferation and selection with oxytetracycline (OTC), while psychrophilic AD was conducive to the removal and control of ARGs if no OTC existed. The diversity and composition of AD bacterial communities were influenced more by temperature than OTC. The dominant genera like Candidatus_Microthrix and Acinetobacter had dramatical abundance discrepancies at different temperatures and were obviously positively correlated with ARGs (tet39, tetC and mexD), mobile genetic elements (MGEs) intI, insert sequences (IS) and plasmid. The physicochemical properties of AD influenced the bacterial richness, which in turn significantly correlated with the ARGs abundances. Therefore, ARGs removal could be potentially optimized by eliminating bacterial hosts with deteriorated living conditions and decreased nutrients. This study clarified the response of antibiotic resistome to different temperature variation and highlighted the potential strategies for improved ARGs removal in AD.Due to the fast reaction of superoxide radical (O2•-) with ozone (O3), it has been suggested that O2•- is present at very low concentrations during ozonation. Therefore, while O2•- has been considered a critical chain carrier for promoting O3 decomposition to hydroxyl radicals (•OH), the direct reactions of O2•- with micropollutants have been assumed to be insignificant during ozonation. In this study, we monitored the exposures of O3, •OH, and O2•- by following the depletion of O3, p-chlorobenzoic acid (pCBA, as •OH probe), and tetrachloromethane (CCl4, as O2•- probe) during ozonation of various water matrices (surface water, groundwater, and secondary wastewater effluent). For a given water matrix, the ratio between •OH and O3 exposures (Rct), O2•- and O3 exposures (RSO), as well as O2•- and •OH exposures (RSH) remained almost constant over the entire reaction time. This suggests that during ozonation, the ratios between the transient concentrations of •OH and O3, O2•- and O3, and O2•- and •OH were also constant and equaled to the Rct, RSO, and RSH, respectively. Based on the O3, •OH, and O2•- exposures observed during ozonation, a chemical kinetic model was proposed to simulate the abatement of ten ozone-resistant micropollutants in the three water matrices by ozonation. The results indicate that due to the higher concentrations of O2•- than •OH (RSH = ~5-8), the reactions with O2•- played a non-negligible or even dominant role in the abatement of some micropollutants that have similar or higher O2•- reactivity than •OH reactivity (e.g., tetrachloroethylene, chloroform, and PFOA). Compared with the previous model that neglected the contribution of O2•- to micropollutant abatement, the proposed model more accurately simulated the abatement efficiencies of the test micropollutants during ozonation. These results indicate that the proposed model can provide a useful tool for the generalized prediction of micropollutant abatement by ozonation.Reservoirs have been constructed as clean energy sources in recent decades with various environmental impacts. Karst rivers typically exhibit high dissolved inorganic carbon (DIC) concentrations, whether and how reservoirs affect carbon cycling, especially organic carbon (OC)-related biogeochemical processes in karst rivers, are unclear. To fill this knowledge gap, multiple tracer methods (including fluorescence excitation-emission matrix (EEM), ultraviolet (UV) absorption, and stable carbon (δ13C) and radiocarbon (Δ14C) isotopes) were utilized to track composition and property changes of both particulate OC (POC) and dissolved OC (DOC) along river-transition-reservoir transects in the Southwest China karst area. The changes in chemical properties indicated that from the river to the reservoir, terrestrial POC is largely replaced by phytoplankton-derived OC, while gradual coloured dissolved organic matter (CDOM) removal and addition of phytoplankton-derived OC to the DOC pool occurred as water flowed to the reservoir. Higher primary production in the transition area than that in the reservoir area was observed, which may be caused by nutrient released from suspended particles. Within the reservoir, the production surpassed degradation in the upper 5 m, resulting in a net DIC transformation into DOC and POC and terrestrial DOM degradation. The primary production was then gradually weakened and microbial degradation became more important down the profile. It is estimated that ~3.1-6.3 mg L-1 (~15.5-31.5 mg-C m-2 (~10-21%)) DIC was integrated into the OC pool through the biological carbon pump (BCP) process in the upper 5 m in the transition and reservoir areas. Our results emphasize the reservoir impact on riverine OC transport, and due to their characteristics, karst areas exhibit a higher BCP potential which is sensitive to human activities (more nutrient are provided) than non-karst areas.
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