作者机构:
[王泓; 陈宏; 杨恩喆; 刘珂; 许荣华] Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province, School of Hydraulic and Environmental Engineering, Changsha University of Science & Technology, Changsha, 410114, China;[范庆元] Shenzhen Water Planning & Design Institute Co., Ltd., Shenzhen, 518000, China;[瞿畏] Changsha Environmental Protection College, Changsha, 410004, China
通讯机构:
[Chen, H.] K;Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province, School of Hydraulic and Environmental Engineering, Changsha University of Science & Technology, Changsha, China
通讯机构:
[Zhe Kong] S;School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China<&wdkj&>National and Local Joint Engineering Laboratory of Municipal Sewage Resource Utilization Technology, Suzhou University of Science and Technology, Suzhou 215009, China<&wdkj&>Jiangsu Collaborative Innovation Center of Water Treatment Technology and Material, Suzhou University of Science and Technology, Suzhou 215009, China
关键词:
*Feammox;*Iron-nitrogen coupling cycle;*Iron-reducing bacteria;*Microbial community
摘要:
Anaerobic ammonium oxidation coupled to Fe(III) reduction, known as Feammox, is a newly discovered nitrogen-cycling process, which serves an important role in the pathways of nitrogen loss in the environment. However, the specific types of microorganisms involved in Feammox currently remain unclear. In this study, we selected two groups of soil samples (paddy and mine), from considerably different habitats in South China, to acclimate Feammox colonies. The Paddy Group had a shorter lag period than the Mine Group, while the ammonium transformation rate was nearly equal in both groups in the mature period. The emergence of the Feammox activity was found to be associated with the increased abundance of iron-reducing bacteria, especially Clostridium_sensu_stricto_12, Desulfitobacterium, Thermoanaerobaculum, Anaeromyxobacter and Geobacter. Ammonium oxidizing archaea and methanogens were dominant among the known archaea. These findings extend our knowledge of the microbial community composition of the potential Feammox microbes from soils under different environmental conditions, which broadens our understanding of this important Fe/N transformation process.
摘要:
Tetracycline (TC) is a widely used pharmaceutical and personal care product (PPCP), and considering its biotoxicity in aquatic systems, the metabolism and stimulation of TC in wastewater purification processes are still deserving of concern. This study reveals the stimulation of TC biodegradation by acetate in bioelectrochemical systems (BESs). Attributed to the abundance of exoelectrogens Geobacter (mainly G. sulfurreducens) and putative TC-degraded bacteria (PTDB) in the electroactive biofilm samples, 94% of 100 mg/L TC decomposed within 48 h. Limited acetate (0.1 g/L, AC-0.1) as a cosubstrate enhanced the removal efficiency of TC by 44% when compared to abundant acetate (1 g/L, AC-1) and controls. This resulted from the enhancement of PTDB and the stability of the Geobacter population under limited acetate stimulation. With the differentiation of the microbial community, ubiquinone and other terpenoid-quinone biosynthesis and histidine metabolism were significantly upregulated in AC-0.1 but downregulated in AC-1, another factor that enhanced the removal efficiency of TCs. Here, we concluded that limited acetate could partially relieve the selective pressure of TC and improve the biodegradation of TC, and the catabolism pathways, as well as the main metabolites, were stimulated by acetate and its concentration.
期刊:
Journal of Marine Science and Engineering,2022年10(11) ISSN:2077-1312
通讯作者:
K. Qu
作者机构:
[Guo, L.; Qu, K.; Huang, J. X.; Li, X. H.] Changsha Univ Sci & Technol, Sch Hydraul & Environm Engn, Changsha 410114, Peoples R China.;[Qu, K.] Key Lab Water Sediment Sci & Water Disaster Preve, Changsha 410114, Peoples R China.;[Qu, K.] Key Lab Dongting Lake Aquat Ecoenvironm Control &, Changsha 410114, Peoples R China.
通讯机构:
[K. Qu] S;School of Hydraulic and Environmental Engineering, Changsha University of Science & Technology, Changsha 410114, China<&wdkj&>Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province, Changsha 410114, China<&wdkj&>Key Laboratory of Dongting Lake Aquatic Eco-Environment Control and Restoration of Hunan Province, Changsha 410114, China
摘要:
Abstract: Many post-disaster surveys have reported on the natural function and effectiveness of fringing reef in preventing the shoreline from the inundation caused by severe weather events. Prior studies mainly focus on the wave propagating, transforming, and breaking on the fringing reefs by assuming that ocean waves propagate in an ideal environment where the wind is absent. However, in the real severe ocean environment, huge surges and waves always occur simultaneously with the strong winds. The wave profile can be easily reshaped by the strong winds, which can also significantly affect the way that ocean waves propagate on the fringing reefs. Therefore, it is necessary to study the hydrodynamics of fringing reefs under the combined action of wind and waves. To study the influences of the onshore wind on the hydrodynamics of solitary wave on the fringing reef, the finite volume method is applied to solve the governing equations of two-phase incompressible flow and a high-resolution numerical wind-wave tank is established in this study. Effects of several main factors are analyzed in detail. The research results show that the onshore wind can significantly increase the maximum wave runup height (maximum by 38.49%) and decrease the wave reflection coefficient of solitary wave (maximum by 8.66%). It is hoped that the research results of this study can enhance the understandings on the hydrodynamics of ocean waves on the fringing reefs during severe weather events. Keywords: wind-wave interaction; solitary wave; fringing reef; two-phase flow; onshore wind
通讯机构:
[Lifen Chen; Changbo Jiang] S;State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian, 116024, China<&wdkj&>School of Hydraulic Engineering, Changsha University of Science & Technology, Changsha, 410114, China
摘要:
In this paper, complex wave interactions with a four-cylinder array is considered, which has clear relevance to supporting columns of certain nearshore/offshore structures and supports so-called near-trapping phenomenon when subjected to water waves of appropriate period and direction. High free surface elevations and wave loading are expected and thus endanger structure safety. A Boussinesq model is established based on the cut-cell technique for dealing with complex geometries with curved surfaces. The model is validated against the experimental measurements for capturing the near-trapping by a four-cylinder structure in a square arrangement, and is extended to investigate the near-trapping for various scenarios. It is found that the wave periods at which the near-trapping occurs increase with the center-to-center spacings between two adjacent cylinders. Moreover, the re-reflection modes that the waves inside the cylinder array are reflected back and forth among neighboring cylinder pairs can be clearly seen from the flow field streamlines. The energy is trapped inside the array and decays slowly due to wave radiation. This trapped wave would eventually meet with the subsequent incident wave crest, leading to high free surface elevations at near-trapping periods. In view of this, two scenarios are designed to avoid/minimize the near-trapping by breaking the geometry symmetry, hence, the re-reflections modes.
期刊:
Journal of Environmental Chemical Engineering,2022年10(4):108168 ISSN:2213-3437
通讯作者:
Hong Chen
作者机构:
[Xie, Min; Zhang, Chengfeng; Wang, Hong; Chen, Hong; Wu, Sha; Liu, Ke; Yang, Enzhe; Chen, Jing] Changsha Univ Sci & Technol, Sch Hydraul Engn, Key Lab Dongting Lake Aquat Eco Environm Control &, Changsha 410114, Peoples R China.;[Xie, Min; Zhang, Chengfeng; Wang, Hong; Chen, Hong; Wu, Sha; Liu, Ke; Yang, Enzhe; Chen, Jing] Key Lab Water Sediment Sci & Water Disaster Preven, Changsha 410114, Peoples R China.;[Chen, Chen] Changsha Social Work Coll, Changsha 410004, Hunan, Peoples R China.
通讯机构:
[Hong Chen] K;Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province, School of Hydraulic Engineering, Changsha University of Science & Technology, Changsha 410114, China<&wdkj&>Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province, Changsha 410114, China
关键词:
Abbreviations DO dissolved oxygen;anammox anaerobic ammonia oxidation;AnAOB anaerobic ammonia-oxidizing bacteria;ANR ammonia nitrogen removal;FA free ammonia;FNA free nitrous acid;HRT hydraulic retention time;NLR nitrogen loading rate;NNR nitrate nitrogen removal rate;NRE total nitrogen removal efficiency;NRR nitrogen removal load;PN/A-AEM one-stage partial nitritation-anammox with airlift enhanced micro-granules;TN total nitrogen concentration;TSS mass of total solids in unit volume of sludge;UASB up-flow anaerobic sludge bed;UBF continuous upflow biofilter;VSS Mass of volatile solids in unit volume of sludge
摘要:
To better understand performance recovery and its mechanism, after the deterioration of an anaerobic ammonia oxidation (anammox) process, experiments were conducted in a UASB reactor. A two-stage anammox reaction was conducted in the reactor, and long-term continuous operation was conducted for 202 d. The mechanism of performance recovery was studied by adjusting the total nitrogen (TN) concentration and hydraulic retention time (HRT) of the influent. The results showed that after the long-term continuous operation, the TN removal efficiency decreased from 88.22 % before deterioration to 11.68 %, and then recovered to 80.63 %. The nitrogen loading rate decreased from 2.25 kg-N/m3/d before deterioration to 0.26 kg-N/m3/d and then recovered to 2.79 kg-N/m3/d. Nitrogen removal load (NRR) decreased from 1.98 kg-N/m3/d to 0.26 kg-N/m3/d before deterioration and recovered to 2.25 kg-N/m3/d. Microbial diversity was analyzed by high-throughput sequencing. During the operation, the dominant anammox strains changed from Candidatus Kuenenia (24.19 %) before deterioration to Candidatus Brocadia (11.90 %) after recovery. The influent TN concentration and HRT were the key factors that affected performance recovery. Reducing the influent TN concentration and shortening the HRT can effectively avoid the inhibition of anammox by the substrate and enable the rapid recovery of nitrogen removal performance. As the microorganisms in the reactor recovered their activity through enrichment, the influent TN gradually increased, and produced NRR higher than the pre-deterioration level, so the reactor performance was fully restored. This study provides a scientific support for recovering the two-stage anammox process performance after deterioration.
通讯机构:
[Hosam Elhegazy] D;Department of Structural Engineering and Construction Management, Faculty of Engineering and Technology, Future University in Egypt, Egypt
关键词:
Key factors;Decision-making;Building projects;Questionnaire survey;Relative importance index;Knowledge gap
摘要:
The success of optimal system selection depends on many factors, such as the nature of the project itself, design team collaboration, team leader's personality, and client input. Unfortunately, despite numerous existing studies on key impacting factors in various fields of construction design, the majority of them failed to focus on the key factors affecting the structure design decision-making process. This study aims to identify, investigate, and rank factors perceived to affect decision-making for the optimal system in the construction industry, particularly that of buildings, during the early stages of the entire life cycle, in terms of their relative importance. Practitioners and experts from Egypt comprising a statistically representative sample, were invited to participate in a structured questionnaire survey to achieve this objective. The questionnaire was composed of 17 factors classified under three primary stage categories: feasibility study, planning, and design and engineering. The relative importance index and dispersion analysis were used to obtain statistics and calculate the collected data. The results show that "The impact of financial difficulties on the decision-making" is the first key factor, "The impact of errors and omissions due to the lack of communication and coordination on the decision-making" is the second key factor, and "The Impact of inaccurate evaluation of projects duration on the decision-making" and "The impact of design changes upon contractor request on the decision-making?" constitute the third key factors. Therefore, this work can guide decision-makers for effective construction management and help achieve a competitive quality and cost-effective project.(c) 2021 THE AUTHORS. Published by Elsevier BV on behalf of Faculty of Engineering, Ain Shams University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/ by-nc-nd/4.0/).
通讯机构:
[Minghua Zhou] K;Key Laboratory of Pollution Process and Environmental Criteria, Ministry of Education, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
关键词:
TiO2 nanotubes;Co-doped boron and cobalt;Flow-through;Electrochemical activation of persulfate;Carbamazepine
摘要:
Degradation of carbamazepine (CBZ) was first conducted by electrochemical activation of persulfate (PS) in flow-through system using boron and cobalt co-doped TiO2 nanotubes (B, Co-TNT) as the anode and carbon felt (CF) as the cathode, achieving a higher removal efficiency than that in beaker mode ascribed to the higher PS decomposition for center dot OH production. Different operating parameters including applied current, initial pH, PS concentration and flow rate were explored, supporting that high current, acidic condition, lofty PS concentration and flow rate were beneficial for the removal of CBZ. The mechanisms of CBZ degradation by electrochemical activation of persulfate in flow-through system were the comprehensive effect of center dot OH, SO4 center dot- and O-1(2), and the possible CBZ degradation pathway was proposed. In summary, B, Co-TNT anode coupled with CF cathode in flow-through system by electrochemical activation of persulfate was an effective method for contaminants degradation.
作者机构:
[Deng, B.; Jiang, C. B.; Zhang, W.] Changsha Univ Sci & Technol, Sch Hydraul & Environm Engn, Changsha 410114, Peoples R China.;[Deng, B.; Jiang, C. B.] Key Lab Water Sediment Sci & Water Disaster Preve, Changsha 410114, Peoples R China.;[Tang, H. S.] CUNY City Coll, Civil Engn Dept, 160 Convent Ave, New York, NY 10031 USA.;[Liu, X. J.] Pearl River Hydraul Res Inst, Guangzhou 510611, Peoples R China.
通讯机构:
[H.S. Tang] C;Civil Engineering Department, The City College of New York, 160 Convent Avenue, New York 10031, United States
关键词:
Bedform;Dam-break bore;Fractal dimension;Hydraulic jump;Sand migration;Swash zone
摘要:
This study makes an experimental study on hydrodynamics and sediment driven by dam-break waves in swash zones of three sandy beaches. The experiment adopts three beaches: a 1:10 uniform-sand beach, a 1:10 non-uniform-sand beach, and a 1:35 non-uniform-sand beach. This paper reports its measurements on swash water depth, morphology, bedload, and migration of sand particles. It also analyzes the hydraulic jump and sandbar, sorting and sedimentology characteristics, and fractal dimension of bedform. The analysis indicates that the uniformness of sand particle sizes plays an important role in hydrodynamic behaviors, bedform evolution, bedload transport, and migration of sand particles. The fractal dimension of beach profiles lies between 1.15 and 1.25 after swash action, despite changes in bed profiles.