Pub Date : 2023-12-01DOI: 10.1016/j.wse.2023.11.007
Guo-fen Hua , Shang-qing Liu , Xiang-dong Liu , Jin-li Li , Yue Fang , Wen-ting Xie , Xiang Xu
Coastal wetlands are hotspots for nitrogen (N) cycling, and crab burrowing is known to transform N in intertidal marsh soils. However, the underlying mechanisms remain unclear. This study conducted field experiments and used indoor control test devices to investigate the seasonal response of nitrogen to crab disturbance at the sediment–water interface in coastal tidal flat wetlands. The results showed that crab disturbance exhibited significant seasonality with large seasonal differences in cave density and depth. Due to crab disturbance, nitrogen fluxes at the sediment–water interface were much greater in the box with crabs than in the box without crabs. In summer, showed a positive flux from the sediment to the overlying water, but and showed positive fluxes from the sediment to the overlying water only in early stages. In winter, showed a positive flux from the sediment to the overlying water, but and both exhibited positive and negative fluxes. These results indicated that the presence of crab burrows can cause the aerobic layer to move downward by approximately 8–15 cm in summer and directly promote nitrification at the sediment surface.
{"title":"Seasonal response of nitrogen exchange fluxes to crab disturbance at sediment–water interface in coastal tidal wetlands","authors":"Guo-fen Hua , Shang-qing Liu , Xiang-dong Liu , Jin-li Li , Yue Fang , Wen-ting Xie , Xiang Xu","doi":"10.1016/j.wse.2023.11.007","DOIUrl":"10.1016/j.wse.2023.11.007","url":null,"abstract":"<div><p>Coastal wetlands are hotspots for nitrogen (N) cycling, and crab burrowing is known to transform N in intertidal marsh soils. However, the underlying mechanisms remain unclear. This study conducted field experiments and used indoor control test devices to investigate the seasonal response of nitrogen to crab disturbance at the sediment–water interface in coastal tidal flat wetlands. The results showed that crab disturbance exhibited significant seasonality with large seasonal differences in cave density and depth. Due to crab disturbance, nitrogen fluxes at the sediment–water interface were much greater in the box with crabs than in the box without crabs. In summer, <span><math><msubsup><mtext>NH</mtext><mn>4</mn><mo>+</mo></msubsup><mo>-</mo><mi>N</mi></math></span> showed a positive flux from the sediment to the overlying water, but <span><math><msubsup><mtext>NO</mtext><mn>2</mn><mo>−</mo></msubsup><mtext>-</mtext><mi>N</mi></math></span> and <span><math><msubsup><mtext>NO</mtext><mn>3</mn><mo>−</mo></msubsup><mtext>-</mtext><mi>N</mi></math></span> showed positive fluxes from the sediment to the overlying water only in early stages. In winter, <span><math><msubsup><mtext>NH</mtext><mn>4</mn><mo>+</mo></msubsup><mtext>-</mtext><mi>N</mi></math></span> showed a positive flux from the sediment to the overlying water, but <span><math><msubsup><mtext>NO</mtext><mn>2</mn><mo>−</mo></msubsup><mtext>-</mtext><mi>N</mi></math></span> and <span><math><msubsup><mtext>NO</mtext><mn>3</mn><mo>−</mo></msubsup><mtext>-</mtext><mi>N</mi></math></span> both exhibited positive and negative fluxes. These results indicated that the presence of crab burrows can cause the aerobic layer to move downward by approximately 8–15 cm in summer and directly promote nitrification at the sediment surface.</p></div>","PeriodicalId":23628,"journal":{"name":"Water science and engineering","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1674237023001187/pdfft?md5=ecffc1324b2de1ec9722880f4e7be518&pid=1-s2.0-S1674237023001187-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138614138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-01DOI: 10.1016/j.wse.2023.12.007
Xiao-xia Lin, Jie Wu, Qi Shi, Wei-xia Gu
{"title":"Preparation and enhanced photocatalytic performance of N-TiO2/g-C3N4 heterostructure for Rhodamine B degradation","authors":"Xiao-xia Lin, Jie Wu, Qi Shi, Wei-xia Gu","doi":"10.1016/j.wse.2023.12.007","DOIUrl":"https://doi.org/10.1016/j.wse.2023.12.007","url":null,"abstract":"","PeriodicalId":23628,"journal":{"name":"Water science and engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139189148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-01DOI: 10.1016/j.wse.2023.11.008
Amir Muhammad Noh Amin Abdul Rahman, A. Rusli, Muhammad Khalil Abdullah, R. K. Shuib, Zuratul Ain Abdul Hamid, Ku Marsilla Ku Ishak, Muaz Mohd Zaini Makhtar, M. Jaafar, M. Shafiq
{"title":"A review of microplastic surface interactions in water and potential capturing methods","authors":"Amir Muhammad Noh Amin Abdul Rahman, A. Rusli, Muhammad Khalil Abdullah, R. K. Shuib, Zuratul Ain Abdul Hamid, Ku Marsilla Ku Ishak, Muaz Mohd Zaini Makhtar, M. Jaafar, M. Shafiq","doi":"10.1016/j.wse.2023.11.008","DOIUrl":"https://doi.org/10.1016/j.wse.2023.11.008","url":null,"abstract":"","PeriodicalId":23628,"journal":{"name":"Water science and engineering","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139022054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-01DOI: 10.1016/j.wse.2023.12.003
M. T. Vu, Viet Thanh Nguyen, Trinh Dinh Lai
{"title":"Accessing impacts of climate change-driven sea level rise on hydrodynamics and sediment dynamics along Ba Lang beaches in Nha Trang Bay, Khanh Hoa, Vietnam","authors":"M. T. Vu, Viet Thanh Nguyen, Trinh Dinh Lai","doi":"10.1016/j.wse.2023.12.003","DOIUrl":"https://doi.org/10.1016/j.wse.2023.12.003","url":null,"abstract":"","PeriodicalId":23628,"journal":{"name":"Water science and engineering","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139025884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-01DOI: 10.1016/j.wse.2023.12.005
Motiur Rahman, Md. Shahjahan Ali
{"title":"Properties of dredged material and potential scope of its beneficial use: A case study of the Pussur River in Bangladesh","authors":"Motiur Rahman, Md. Shahjahan Ali","doi":"10.1016/j.wse.2023.12.005","DOIUrl":"https://doi.org/10.1016/j.wse.2023.12.005","url":null,"abstract":"","PeriodicalId":23628,"journal":{"name":"Water science and engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139190340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-25DOI: 10.1016/j.wse.2023.11.006
Wei He , Chao Yu , Xiao-dong Yu , Jian Zhang , Jose G. Vasconcelos , Hui Xu , Shou-ling Chen
Deep storage tunnels (DSTs) are used in densely urbanized areas to relieve stormwater collection systems, thereby reducing urban floods and runoff pollution, due to their substantial storage capacity. The computation of the hydraulic characteristics and flow trajectories of DSTs under rapid filling scenarios can help to predict sediment deposition and pollutant accumulation associated with the stored runoff, as well as the likelihood of operational problems, such as excessive surging. However, such assessments are complicated by various inflow scenarios encountered in tunnel systems during their operation. In this study, the Suzhou River DST in China is selected as a study case. Particles were tracked, and hydraulic analysis was conducted with scaled model experiments and numerical models. The flow field, particle movement, air‒water phase, and pressure patterns in the DST were simulated under various one- and two-sided inflow scenarios. The results showed that with regards to the design conditions involving two-sided inflows, flow reversals occurred with stepwise increases in the water surface and pressure. In contrast, this phenomenon was not observed under the one-sided inflow scenario. Under the asymmetric two-sided inflow scenarios, water inflows led to particle accumulation near the shaft, reducing the received inflows. However, under the symmetric inflow conditions, particles were concentrated near the middle of the tunnel. Compared to those under the symmetric inflow scenario, asymmetric inflow caused surface wave and entrapped air reductions. This study could provide support for regulation of the inflow of the Suzhou River DST and for prediction of sediment and pollutant accumulation.
{"title":"Hydraulic characteristics and flow trajectories under two-sided asymmetric inflow conditions for a deep storage tunnel system","authors":"Wei He , Chao Yu , Xiao-dong Yu , Jian Zhang , Jose G. Vasconcelos , Hui Xu , Shou-ling Chen","doi":"10.1016/j.wse.2023.11.006","DOIUrl":"10.1016/j.wse.2023.11.006","url":null,"abstract":"<div><p>Deep storage tunnels (DSTs) are used in densely urbanized areas to relieve stormwater collection systems, thereby reducing urban floods and runoff pollution, due to their substantial storage capacity. The computation of the hydraulic characteristics and flow trajectories of DSTs under rapid filling scenarios can help to predict sediment deposition and pollutant accumulation associated with the stored runoff, as well as the likelihood of operational problems, such as excessive surging. However, such assessments are complicated by various inflow scenarios encountered in tunnel systems during their operation. In this study, the Suzhou River DST in China is selected as a study case. Particles were tracked, and hydraulic analysis was conducted with scaled model experiments and numerical models. The flow field, particle movement, air‒water phase, and pressure patterns in the DST were simulated under various one- and two-sided inflow scenarios. The results showed that with regards to the design conditions involving two-sided inflows, flow reversals occurred with stepwise increases in the water surface and pressure. In contrast, this phenomenon was not observed under the one-sided inflow scenario. Under the asymmetric two-sided inflow scenarios, water inflows led to particle accumulation near the shaft, reducing the received inflows. However, under the symmetric inflow conditions, particles were concentrated near the middle of the tunnel. Compared to those under the symmetric inflow scenario, asymmetric inflow caused surface wave and entrapped air reductions. This study could provide support for regulation of the inflow of the Suzhou River DST and for prediction of sediment and pollutant accumulation.</p></div>","PeriodicalId":23628,"journal":{"name":"Water science and engineering","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1674237023001175/pdfft?md5=e5fb1166e1e3a54eb1918b8aab874440&pid=1-s2.0-S1674237023001175-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139291443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-22DOI: 10.1016/j.wse.2023.11.003
Sevda Jalali Milani, Gholamreza Nabi Bidhendi
Globalization has led to a rapid rise in energy consumption, making climate change one of the world's most pressing issues. As wastewater treatment plants (WWTPs) contribute to climate change by emitting greenhouse gases (GHGs), this study estimated the total GHG emissions of WWTPs by classifying them as either direct or indirect carbon emissions. The effectiveness of the use of solar photovoltaic systems and biogas produced by WWTPs in increasing energy recovery and reducing GHG emissions was investigated. This study demonstrated that the use of an up-flow anaerobic sludge blanket (UASB) reactor with a biogas flow of 9 120.77 m3/d and an activated sludge processing system (ASPS) reactor with a biogas flow of 14 004 m3/d, in addition to the energy production from the UASB reactor (6 421.8 MW⸱h per year) and the ASPS reactor (9 860.0 MW⸱h per year), yielded a reduction of 3 316.85 and 5 092.69 t of CO2 equivalent per year, respectively. Furthermore, the co-design of wastewater processes could be utilized to optimize biogas energy recovery. Moreover, the use of solar photovoltaic systems reduced GHG emissions from WWTPs. This is important to the transition to renewable energy because it resulted in a 10%–40% reduction in carbon emissions from WWTPs. Integrating renewable energy sources, biogas, and solar energy could provide up to 88% of the annual energy requirements of WWTPs. Recommendations are provided for further research considering the limited availability of integrated resources for studying the simultaneous utilization of photovoltaic and biogas systems.
{"title":"Biogas and photovoltaic solar energy as renewable energy in wastewater treatment plants: A focus on energy recovery and greenhouse gas emission mitigation","authors":"Sevda Jalali Milani, Gholamreza Nabi Bidhendi","doi":"10.1016/j.wse.2023.11.003","DOIUrl":"10.1016/j.wse.2023.11.003","url":null,"abstract":"<div><p>Globalization has led to a rapid rise in energy consumption, making climate change one of the world's most pressing issues. As wastewater treatment plants (WWTPs) contribute to climate change by emitting greenhouse gases (GHGs), this study estimated the total GHG emissions of WWTPs by classifying them as either direct or indirect carbon emissions. The effectiveness of the use of solar photovoltaic systems and biogas produced by WWTPs in increasing energy recovery and reducing GHG emissions was investigated. This study demonstrated that the use of an up-flow anaerobic sludge blanket (UASB) reactor with a biogas flow of 9 120.77 m<sup>3</sup>/d and an activated sludge processing system (ASPS) reactor with a biogas flow of 14 004 m<sup>3</sup>/d, in addition to the energy production from the UASB reactor (6 421.8 MW⸱h per year) and the ASPS reactor (9 860.0 MW⸱h per year), yielded a reduction of 3 316.85 and 5 092.69 t of CO<sub>2</sub> equivalent per year, respectively. Furthermore, the co-design of wastewater processes could be utilized to optimize biogas energy recovery. Moreover, the use of solar photovoltaic systems reduced GHG emissions from WWTPs. This is important to the transition to renewable energy because it resulted in a 10%–40% reduction in carbon emissions from WWTPs. Integrating renewable energy sources, biogas, and solar energy could provide up to 88% of the annual energy requirements of WWTPs. Recommendations are provided for further research considering the limited availability of integrated resources for studying the simultaneous utilization of photovoltaic and biogas systems.</p></div>","PeriodicalId":23628,"journal":{"name":"Water science and engineering","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S167423702300114X/pdfft?md5=d6a75ed56c58ecbb4102973c36f262a7&pid=1-s2.0-S167423702300114X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139297627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-22DOI: 10.1016/j.wse.2023.11.004
Wei He , Si-yuan Feng , Jian Zhang , Hong-wu Tang , Yang Xiao , Sheng Chen , Chun-sheng Liu
Lateral intakes are common in rivers. The pump efficiency and sediment deposition are determined by the local hydrodynamic characteristics and mainstream division width. The hydraulic characteristics of lateral withdrawal from inclined river slopes at different intake elevations should be investigated. Meanwhile, the division width exhibits significant vertical non-uniformity at an inclined river slope, which should be clarified. Hence, a three-dimensional (3-D) hydrodynamic and particle-tracking model was developed with the Open Source Field Operation and Manipulation (OpenFOAM), and the model was validated with physical model tests for 90° lateral withdrawal from an inclined side bank. The flow fields, withdrawal sources, and division widths were investigated with different intake bottom elevations, withdrawal discharges, and main channel velocities. This study showed that under inclined side bank conditions, water entered the intake at an oblique angle, causing significant 3-D spiral flows in the intake rather than two-dimensional closed recirculation. A lower withdrawal discharge, a lower bottom elevation of the intake, or a higher main channel velocity could further strengthen this phenomenon. The average division width and turbulent kinetic energy were smaller under inclined side bank conditions than under vertical bank conditions. With a low intake bottom elevation, a low withdrawal discharge, or a high main channel velocity, the sources of lateral withdrawal were in similar ranges near the local inclined bank in the vertical direction. Under inclined slope conditions, sediment deposition near the intake entrance could be reduced, compared to that under vertical slope conditions. The results provide hydrodynamic and sediment references for engineering designs for natural rivers with inclined terrains.
{"title":"Hydrodynamic characteristics and particle tracking of 90° lateral intakes at an inclined river slope","authors":"Wei He , Si-yuan Feng , Jian Zhang , Hong-wu Tang , Yang Xiao , Sheng Chen , Chun-sheng Liu","doi":"10.1016/j.wse.2023.11.004","DOIUrl":"10.1016/j.wse.2023.11.004","url":null,"abstract":"<div><p>Lateral intakes are common in rivers. The pump efficiency and sediment deposition are determined by the local hydrodynamic characteristics and mainstream division width. The hydraulic characteristics of lateral withdrawal from inclined river slopes at different intake elevations should be investigated. Meanwhile, the division width exhibits significant vertical non-uniformity at an inclined river slope, which should be clarified. Hence, a three-dimensional (3-D) hydrodynamic and particle-tracking model was developed with the Open Source Field Operation and Manipulation (OpenFOAM), and the model was validated with physical model tests for 90° lateral withdrawal from an inclined side bank. The flow fields, withdrawal sources, and division widths were investigated with different intake bottom elevations, withdrawal discharges, and main channel velocities. This study showed that under inclined side bank conditions, water entered the intake at an oblique angle, causing significant 3-D spiral flows in the intake rather than two-dimensional closed recirculation. A lower withdrawal discharge, a lower bottom elevation of the intake, or a higher main channel velocity could further strengthen this phenomenon. The average division width and turbulent kinetic energy were smaller under inclined side bank conditions than under vertical bank conditions. With a low intake bottom elevation, a low withdrawal discharge, or a high main channel velocity, the sources of lateral withdrawal were in similar ranges near the local inclined bank in the vertical direction. Under inclined slope conditions, sediment deposition near the intake entrance could be reduced, compared to that under vertical slope conditions. The results provide hydrodynamic and sediment references for engineering designs for natural rivers with inclined terrains.</p></div>","PeriodicalId":23628,"journal":{"name":"Water science and engineering","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1674237023001151/pdfft?md5=4bf6740fac8cfd81551cb53ec6b9ace4&pid=1-s2.0-S1674237023001151-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139292139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The completely autotrophic nitrogen removal over nitrite (CANON) is a new type of nitrogen removal process developed in recent years. The control of dissolved oxygen (DO) in this process is relatively stringent, especially in low-substrate wastewater treatment. However, the results of studies on the operation of the process in different aeration modes are still controversial, and investigations on biofilm type CANON reactors are limited. In this study, a pilot-scale CANON bioreactor filled with suspended carriers was investigated on the treatment of wastewater at low ammonium concentrations, and the effect of the aeration mode on autotrophic nitrogen removal was evaluated. Seven conditions with various aeration on/off times and DO levels were tested. The results showed that an intermittent aeration with a 20-min/20-min aeration on/off time and DO concentrations of 1.0–1.3 mg/L at the end of the aeration period was appropriate, potentially inhibiting nitrite oxidizing bacteria (NOB) and keeping the total nitrogen (TN) removal rate at a relatively high level of 76.7% ± 2.5%. In the optimal aeration mode, the reactor achieved effluent TN and concentrations of (11.1 ± 3.3) mg/L and (3.6 ± 2.3) mg/L, respectively, with a hydraulic retention time of 12 h and an influent concentration of (48.6 ± 9.4) mg/L at 30.1°C ± 2.2°C. The results of metagenomic sequencing for microorganisms on carriers indicated that the main nitrogen removal bacteria in the reactor were Proteobacteria, Planctomycetes, and Nitrospirae. The NOB genus Nitrospira was completely inhibited by intermittent aeration. Candidatus Kuenenia had strong adaptability to low-concentration wastewater.
{"title":"Effect of aeration on low-substrate CANON process","authors":"Qiong-qiong Xia, Wei Shang, Xing-can Zheng, Wen-an Zhang, Ya-xiong Wang, Yong-li Sun, Peng-feng Li","doi":"10.1016/j.wse.2023.11.005","DOIUrl":"10.1016/j.wse.2023.11.005","url":null,"abstract":"<div><p>The completely autotrophic nitrogen removal over nitrite (CANON) is a new type of nitrogen removal process developed in recent years. The control of dissolved oxygen (DO) in this process is relatively stringent, especially in low-substrate wastewater treatment. However, the results of studies on the operation of the process in different aeration modes are still controversial, and investigations on biofilm type CANON reactors are limited. In this study, a pilot-scale CANON bioreactor filled with suspended carriers was investigated on the treatment of wastewater at low ammonium concentrations, and the effect of the aeration mode on autotrophic nitrogen removal was evaluated. Seven conditions with various aeration on/off times and DO levels were tested. The results showed that an intermittent aeration with a 20-min/20-min aeration on/off time and DO concentrations of 1.0–1.3 mg/L at the end of the aeration period was appropriate, potentially inhibiting nitrite oxidizing bacteria (NOB) and keeping the total nitrogen (TN) removal rate at a relatively high level of 76.7% ± 2.5%. In the optimal aeration mode, the reactor achieved effluent TN and <span><math><msubsup><mtext>NH</mtext><mn>4</mn><mo>+</mo></msubsup><mtext>-</mtext><mi>N</mi></math></span> concentrations of (11.1 ± 3.3) mg/L and (3.6 ± 2.3) mg/L, respectively, with a hydraulic retention time of 12 h and an influent <span><math><msubsup><mtext>NH</mtext><mn>4</mn><mo>+</mo></msubsup><mtext>-</mtext><mi>N</mi></math></span> concentration of (48.6 ± 9.4) mg/L at 30.1°C ± 2.2°C. The results of metagenomic sequencing for microorganisms on carriers indicated that the main nitrogen removal bacteria in the reactor were Proteobacteria, Planctomycetes, and Nitrospirae. The NOB genus <em>Nitrospira</em> was completely inhibited by intermittent aeration. <em>Candidatus Kuenenia</em> had strong adaptability to low-concentration wastewater.</p></div>","PeriodicalId":23628,"journal":{"name":"Water science and engineering","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1674237023001163/pdfft?md5=9279a43348416861ef64f9c92d14a4d7&pid=1-s2.0-S1674237023001163-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139295331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-15DOI: 10.1016/j.wse.2023.11.001
Lin Hu , Lin Chen , Xian-kun Wu , Rui Luo , Rong-guan Lv , Zheng-hao Fei , Feng Yang
Removal of uranium(VI) from nuclear wastewater is urgent due to the global nuclear energy exploitation. This study synthesized novel sponge-like 3D porous materials for enhanced uranium adsorption by combining electrospinning and fibrous freeze-shaping techniques. The materials possessed an organic–inorganic hybrid architecture based on the electrospun fibers of polyacrylonitrile (PAN) and SiO2. As a supporting material, the surface of fibrous SiO2 could be further functionalized by cyano groups via (3-cyanopropyl)triethoxysilane. All the cyano groups were turned into amidoxime (AO) groups to obtain a amidoxime-functionalized sponge (PAO/SiO2-AO) through the subsequent amidoximation process. The proposed sponge exhibited enhanced uranium adsorption performance with a high removal capacity of 367.12 mg/g, a large adsorption coefficient of 4.0 × 104 mL/g, and a high removal efficiency of 97.59%. The adsorption kinetics perfectly conformed to the pseudo-second-order reaction. The sorbent also exhibited an excellent selectivity for with other interfering metal ions.
{"title":"Efficient removal of U(VI) from wastewater by a sponge-like 3D porous architecture with hybrid electrospun nanofibers","authors":"Lin Hu , Lin Chen , Xian-kun Wu , Rui Luo , Rong-guan Lv , Zheng-hao Fei , Feng Yang","doi":"10.1016/j.wse.2023.11.001","DOIUrl":"10.1016/j.wse.2023.11.001","url":null,"abstract":"<div><p>Removal of uranium(VI) from nuclear wastewater is urgent due to the global nuclear energy exploitation. This study synthesized novel sponge-like 3D porous materials for enhanced uranium adsorption by combining electrospinning and fibrous freeze-shaping techniques. The materials possessed an organic–inorganic hybrid architecture based on the electrospun fibers of polyacrylonitrile (PAN) and SiO<sub>2</sub>. As a supporting material, the surface of fibrous SiO<sub>2</sub> could be further functionalized by cyano groups via (3-cyanopropyl)triethoxysilane. All the cyano groups were turned into amidoxime (AO) groups to obtain a amidoxime-functionalized sponge (PAO/SiO<sub>2</sub>-AO) through the subsequent amidoximation process. The proposed sponge exhibited enhanced uranium adsorption performance with a high removal capacity of 367.12 mg/g, a large adsorption coefficient of 4.0 × 10<sup>4</sup> mL/g, and a high removal efficiency of 97.59%. The <span><math><mrow><msubsup><mtext>UO</mtext><mn>2</mn><mrow><mn>2</mn><mo>+</mo></mrow></msubsup></mrow></math></span> adsorption kinetics perfectly conformed to the pseudo-second-order reaction. The sorbent also exhibited an excellent selectivity for <span><math><mrow><msubsup><mtext>UO</mtext><mn>2</mn><mrow><mn>2</mn><mo>+</mo></mrow></msubsup></mrow></math></span> with other interfering metal ions.</p></div>","PeriodicalId":23628,"journal":{"name":"Water science and engineering","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1674237023001126/pdfft?md5=c350de37006f4cd7e95054f7660984b4&pid=1-s2.0-S1674237023001126-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139301763","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}